Another Newbie Post - M1078 General Misc and Drive Train Conversation

[REDee]

Hello All ..

First time poster - please be kind

I am sure that most of these questions have been addressed ... but I am trying to put all my questions in one place, if this already exists, let me know and I'll hang my head low and move on.

I love the looks, the idea, the size of the M1078 ... and the (apparent) value for what you can get.

I am considering (like so many others here) getting an M1078 with the end goal of designing a go anywhere tiny house.

Moving past the standard things anyone should do when they buy - including - but not limited to - checking replacing seals / drive shaft inspection and balancing / air brake checks / etc ... (looking for more things to add to a check list). Here are some of my questions ...

Tires & Wheels - I see the usual internet banter on why my tire is better than yours, and I know that every tire ever made was made with a specific purpose in mind. My question is a bit more general ... is it possible to use a different tire and wheel combo than the 'stock' design and maintain the CTIS functionality? New tires are very expensive - used tires may have exceeded their 'recommended shelf / service life'. Could you change to a tire size / design that would serve well as an all season tire for 80% highway service? Something you could go down to the local 'big truck' tire shop and buy?

Engine Tuning - Again - when it comes to the 3116 power plant - this is like the classic Ford -VS- Chevy argument. My question is after we move to the place where we agree that the 3116 has a place ... are there recommendations we can all agree on for different tunes / programming / setups?

High Speed Gears / Operation - This really rolls both items together ... I'm not in a hurry - but from what I have seen perhaps the 'stock' military setup wasn't designed for a civilian to take his family to the lake in What I would like to avoid is having to continually keep the pedal all the way down , operating the engine at a point far away from peak efficiency, with suspect tires I am happy to roll along at 60-65 mph ... but I'd like to feel it was more 'effortless' than a struggle. Thoughts / recommendations / opinions???

When You Need Help - When repairs or engine programming gets to the point that you are unable to do it on your own ... what have you done? Have local Allison or CAT shops been helpful?

When You Need Parts - Have you been successful in getting the parts you need from local Allison or CAT shops or on line?

Once the general running gear is set and safe - what are your experiences / understanding of the 'stock' paint finish? Specifically I would like to paint a unit if I got one - and I have read / heard everything from the paint is like a common Imron / polyurethane enamel that requires some caution - to the paint is super dangerous / worse than your worst asbestos[FONT=Roboto, arial, sans-serif] fears come true - to its really no big deal. My expectation is the truth is somewhere in the middle.

Giant post I know - tons of questions - again ... feel free to point / link to other posts. One thing I've seen here is that there is a TON of information, its not easy to always sort through it all - and you all are passionate about helping / arguing about these cool trucks! [/FONT]

Thanks!!!!

 

[coachgeo]

before you ask all that... suggest you read the threads on these topics so knowledgeable folk don't go.... "ohhhh geeeez..... this fellow wants me to repeat myself for the 500th time" that burns out good knowledgeable members so freakin fast... they begin to run for the hills and stop coming back.

so READ SEARCH... READ SOME MORE followed by more search etc. After reading... ask appropriate questions in threads already existing on a topic. That is just plain ol Netiquiet!!!

btw.... there is a seperate forum in here all about paint and body work of MV's with ton of great info. You need to read up on CARC

look forward to your participation in threads.

 

[REDee]

Thanks - understood .... is there an area that addresses such items as a wholistic / system level?

If you think it is appropriate I willl gladly delete my post


PS - just sent the webmaster a request on how to delete.

 

[snowtrac nome]

going to a smaller tire diameter will lower your gear ratio and suck up all the gains you got from the high speed gear set there are wide duplex tires out there the ctis would have to be defeated to accommodate 22.5 wheels also the off set might not be quite right. the good year tires have the best speed rating and when used on Oshkosh snow removal equipment can be pumped up to 80 psi which might make the tires last longer on asphalt. My truck spends 90 percent of its time on gravel and a hundred percent of its high speed usahe is on gravel so I opted to leave mine alone the way it is and it has served me well. The 3116 valve springs are kind of wimpy so the engine cant be governed much above where it is with out damage happening, and to get more hp requires more fuel which equates to worse fuel mileage. these are some things to think about if you want commercial all season tires for on asphalt longevity than maybe look at dropping in a power joke engine tat can spin to over 3000 rpm but you will drink fuel.

 

[Suprman]

The driveshafts are already humming away with 2-1 reduction at the hubs. Highway driving already causes wear on the slip joints. Making the trans and drivetrain spin faster is not advisable.

 

[NDT]

Parts support for these trucks is abysmal at best. There is no one place you can call that has everything. Some parts come from Cat, some from FinditParts, some from ebay, some from FMTVtrucks.com. I would not BEGIN to consider sinking 6 digits into one of these trucks to make a camper, only to have it break down every outing. The picture is one that was stuck at a repair shop near me for a month.

 

[Suprman]

Looks nice. At least the guy had a neat lawn ornament. If you are good at working on trucks and you can do all the work yourself then you should be ok. If you have to pay someone else to do everything then you will need deep pockets. Good to have a spare truck around.

 

[coachgeo]

Parts support for these trucks is abysmal at best. There is no one place you can call that has everything. Some parts come from Cat, some from FinditParts, some from ebay, some from FMTVtrucks.com. I would not BEGIN to consider sinking 6 digits into one of these trucks to make a camper, only to have it break down every outing. The picture is one that was stuck at a repair shop near me for a month.

who knows why it sat there... mine sat like that for months on end only cause I cut labor cost by having them do things at slow times.. Worked perfect since my ability to go fetch it was massively limited.

But that being said..... and you know more than I..... is it really that hard to find someone to work on a CAT engine? CAT and allison trannies similar to ones in these trucks are in thousands of motorhomes and school busses. fire engines and dump trucks.. would it be that hard to find someone for that? The big rig shop I got towed too had a mechanic with 20yrs of Allison experience.... don't know if that is rare or not.. they had zero problems with experience . EXCEPT for the alternator.. that confused them. They ended up taking my (actually Suprmans) suggestion to check the excite wire after their go to alternator shop said alternator was bad ... excite wire was the problem and they replaced it. Alternator was fine.

 

[cucvmule]

Welcome and be patient. If and when I acquire one of these Trucks I will get two more for accessible parts. Read and read more, these are special trucks for a reason. Read Archives

As for mobile house on wheels, and pulling a trailer, well there is equipment out in the civi market also that may be better suited for parts acquisition should you get hung up somewhere. Read Archives

Do some reading for a couple days and you will find that you will need to read more. As for cost to get started the old adage you get what you pay for still applies to MV's also. And also being mechanically proficient with said vehicle in case of problems. You would know more than most shops because you own one and they have never seen one up close. Dig

Buy a great low mileage, time vehicle with new tires on it, great equipment from a reputable vendor as on Steel Soldiers and have some piece of mind that you are starting with great equipment to start with. The vendors on here are well experienced and can certainly help with some of your goals in living large in this Great Country.

Good Luck and The Most Dangerous Place on Earth is the Open Road.

 

[REDee]

Thank you all - I've read quite a bit and have more questions now then when I started

As far as vehicle speed goes I'm not looking for land speed records ... 65 would be just fine ... more importantly from what I have seen (and I could be super off base - I never found exact curve on this tune / setup) it looks like the 3116 peak torque performance is closer to 1800 RPM ... which makes re-gearing the differentials look attractive, or at least interesting. Looks like that would reduce engine, transmission, drive shaft wear and possibly set you at a more efficient operating point (at least for my initial intended application). Not to mention reducing of sound pressure in the cab. Also - it looks like new(ish) Goodyear ratings seem to imply there is a G range 395/85R20 MVT good for 81 MPH - so brake capacity and drivetrain issues are two big concerns for running over the 55-58 initial design speed. (Remind me to use caution around those claiming high speeds with giant tires rated at 60 mph.)

I'm still concerned / confused about painting and refinishing ... lots of opinions out there. No one should ever sand industrial coatings without some sort of PPE ... I'll keep digging and reading.

And lastly - In looking at my plans it looks like I would need closer to 16' of 'box' behind me. That puts me looking at the M1083 (which I think could handle the ~2 feet off hang). I'm not sure how the M1083 fits in with my initial thoughts. I might have to reboot and look at medium duty freightliner or bus or something else ... I might just need a M1078 to make parts or burger runs

The life of a dreamer ....

 

[coachgeo]

....As far as vehicle speed goes I'm not looking for land speed records ... 65 would be just fine .......

65 peak downhill; with a trail wind, very possible... 65mph average cruising ain't gonna happen even with existing higher ratio and tires and not be pushing the engine outside its parameters that would give it a long life. One could get marginally closer with existing higher ratio (which is an oxymoron) and 53" tires but that presents other issues. There is a remote chance of other ratios higher than what is available now becoming available in the future. slim chance...... but a chance.

 

[scottmandu]

I've found that parts availability on the LMTY is only surpassed by the humvee. Parts are more easy to come by than a 5 ton or a deuce. My local caterpillar and Allison dealers have had everything needed in stock. I've had to order U joints and seals which took a few days, and most cab parts have to some from Europe which is a week trip, but I've never had an LMTV leave me on the side of the road (knock on wood) (except for the time I left the water drain in the fuel filter open..). The most difficult single item to find is the alternator, but neihoff supports them rather well and my local Niehoff dealer has been able to rebuild alternators in 2-3 days (at a cost though).

 

[scottmandu]

65 peak downhill; with a trail wind, very possible.... 65mph average cruising....

I've hit 61 with stock gears going Downhill with a tail wind. 65 isn't possible without the 6.14 ratio axles unless you increase the max engine RPM which is probably not a good idea.

And lastly - In looking at my plans it looks like I would need closer to 16' of 'box' behind me. That puts me looking at the M1083 (which I think could handle the ~2 feet off hang). I'm not sure how the M1083 fits in with my initial thoughts. I might have to reboot and look at medium duty freightliner or bus or something else ... I might just need a M1078 to make parts or burger runs
The life of a dreamer ....

The 6X6 is a good truck, but it will eat up the rear tires with city driving. You will also need a CDL to operate as it's GVW exceeds 26000lbs. You also loose about 20% fuel economy with the 6X6. I get about 5.5 mpg in my 1084A1. My M1078 returns about 7 mpg city cycle.

 

[spankybear]

Well my truck is sitting and has been for awhile because I don't have any time to work on it. The evil corporation I work for isn't allowing me many days off... 2 days off in the last 30 days...

 

[REDee]

Thanks all ...

Maybe I need a M1078 just for fun ... and need to look for something else for my overland / expedition / RV project. I need at least 16 - 20 feet of habit space for my plans. Any recommendations for other military vehicles as a starting point? The plan is 80% highway / 20% off road capable.

Cant say thanks enough.

 

[coachgeo]

c

Thanks all ...

Maybe I need a M1078 just for fun ... and need to look for something else for my overland / expedition / RV project. I need at least 16 - 20 feet of habit space for my plans. Any recommendations for other military vehicles as a starting point? The plan is 80% highway / 20% off road capable.

Cant say thanks enough.

That is potentially better question for folk at Expedition Portal. So far though you have offered way too few variables to offer advice. Thus wherever you seek advice suggest you offer much more information; as in you say "military Vehicle starting point".... are you limiting to US military? Why limit to military (Mitsubishi Fuso is known to be a real good expedition camper base truck). What is your mechanical skill set? What is your budget? What is your 20% offroad (forest service roads, hunters trails, mostly desert terrain etc). Will you probably go for RV parks or extended boondocking?? If your considering vehicles manufactured outside of US (military or not.. but available in US) then Expedition Portal maybe best place to ask for there is probably a larger range of world wide truck knowledge there. Example the German MB 914.

 

[Aernan]

Hello All ..1. I love the looks, the idea, the size of the M1078 ... and the (apparent) value for what you can get.
2. Moving past the standard things anyone should do when they buy - including - but not limited to - checking replacing seals / drive shaft inspection and balancing / air brake checks / etc ... (looking for more things to add to a check list). Here are some of my questions ...
3. Tires & Wheels - I see the usual internet banter on why my tire is better than yours, and I know that every tire ever made was made with a specific purpose in mind. My question is a bit more general ... is it possible to use a different tire and wheel combo than the 'stock' design and maintain the CTIS functionality? New tires are very expensive - used tires may have exceeded their 'recommended shelf / service life'. Could you change to a tire size / design that would serve well as an all season tire for 80% highway service? Something you could go down to the local 'big truck' tire shop and buy?
4. Engine Tuning - Again - when it comes to the 3116 power plant - this is like the classic Ford -VS- Chevy argument. My question is after we move to the place where we agree that the 3116 has a place ... are there recommendations we can all agree on for different tunes / programming / setups?
5. High Speed Gears / Operation - This really rolls both items together ... I'm not in a hurry - but from what I have seen perhaps the 'stock' military setup wasn't designed for a civilian to take his family to the lake in What I would like to avoid is having to continually keep the pedal all the way down , operating the engine at a point far away from peak efficiency, with suspect tires I am happy to roll along at 60-65 mph ... but I'd like to feel it was more 'effortless' than a struggle. Thoughts / recommendations / opinions???
6. When You Need Help - When repairs or engine programming gets to the point that you are unable to do it on your own ... what have you done? Have local Allison or CAT shops been helpful?
7. When You Need Parts - Have you been successful in getting the parts you need from local Allison or CAT shops or on line?
8. Once the general running gear is set and safe - what are your experiences / understanding of the 'stock' paint finish? Specifically I would like to paint a unit if I got one - and I have read / heard everything from the paint is like a common Imron / polyurethane enamel that requires some caution - to the paint is super dangerous / worse than your worst asbestos fears come true - to its really no big deal. My expectation is the truth is somewhere in the middle.

1. We all love the looks of the truck and you can buy them for basically a buck a pound which is amazing.

2. If you have money and little mechanical skill you can buy a refurbished truck which will save you a pile of searching for parts and becoming an expert at each sub system.
Things you must check/change post purchase:
- drive shaft "hinge out angle"
- change tranmission to ATF
- change all fluids. Get oil analysis started
- likely replace the batteries (all four of them 6tl)
- Make sure alternator is powering batteries
- Make CTIS work (fix leaks replace controller/solenoids as necessary)

A list of things that may go bad:
- anything rubber is going bad so that means, coolant lines, axle seals, hydraulic seals, bulbs
- batteries
- rubber issolators
- tires

3. tires/wheels
you have a choice of basically two tires. the 46 and the 53. They are offroad tires and you can only buy the surplus. They are very reasonably priced and there are no alternatives AFAIK. Likely remove the run flat element.

4. Engine Tuning
This is a polarizing topic. Cat actually did a great job of tuning from the factory but if you can keep it cool enough you can sqweeze more power out. There is an updated turbo. Beyond that you can do methanol/water injection, bypass oil filter, wrap the intercooler lines, wrap the exhaust, add additional oil coolers. If you don't mind shortening the engine life you could mess with propane injection. Once you do get the engine too hot you will destroy the rings and piston liner which is not replaceable. The block will need to removed and re-bored. If you want the best engine possible cat a very new truck with the cat C7 in it. Since the focus of the project is the house portion I would leave performance tuning to last.

5. high speed gears
Yes do it. Finding them is near impossible. The 3.07 ratio is good but people have mentioned if a 2.90 ratio existed it would be better because these motors have limited RPM and produce massive torque at lower RPMs. The tires are not really rated for high speeds so no matter how many modifications you make I'm certain you won't want to be driving 80 mph in the truck. Of note the A1 trucks do have ABS.

6. When you need help
If you tell people you have all "all american" truck with Cat motor they will want to work on it. The local Cat dealer can do the engine but I'm not sure what else. I did have the drive shafts built at a local shop and installed at another. One of those shops mentioned a couple showed up with a Unimog and they turned them away because they knew nothing about mogs and can not source parts for them. BTW I live in San Jose California. Not a small town. If you get the 3116 it's all mechanical. You set and forget it and then just do regular adjustments. Other motors require a laptop and cat software. No one does anything to the transmission except change fluid. If it goes bad chances are you will swap it with another working one.

7. All parts on the truck have a NSN. With effort you can find the civilian part number. Once you have that you can hunt for the part. Some things are salvage/used and others are new old stock with some small consumables being still in production. For example the cab tilts. There is a hydraulic latch. The seals go bad. There are people refurbishing them and selling them or repair for a core. You would never find that civilian part. But the engine oil filters are new and any lines or hoses can be found new. The truck much to my surprise is just another large commercial truck. I get my bolts at home depot as grade 8.8. Any hydraulics shop can make hoses for it. All the fluids are very standard and common to find. There are a lot of surplus parts and with some effort you can get anything you need so far.

8. Chemical Agent Resistant Coating (CARC)
It's like spray in bed liner. It's very tough and doesn't fade or crack. You can get replacement paints. You would be best off getting modern CARC mixed the color you like and painting over the truck instead of strip and paint. The reason for this is the truck is galvanized to avoid rust and any paint removal that works on CARC will take that off. If you really feel strongly then look at "dustless blasting" it's a wet sand blasting technique that is cheap and avoids inhaling the CARC.

Personally I have taken my truck offroading and drug it along some manzanita and oak trees which would typically scratch the paint badly and it did nothing. It did leave green marks which I power washed off. The paint is amazing and you should keep it.


-----
Why a LMTV over a unimog, pinzgaur, g-wagen, F-350, Sportster, Fuzio etc.

1. Cheap truck
2. Very capable off road out of the box.
22" of ground clearance. Giant tires which are bead locked and CTIS. Does not have a locker and you can't get them. Can get detroit style for rear.
3. Total capacity.
5 tons in bed on road. 2.5 off road recommended (from what I am told). The bed weighs 1200 lbs so you get a bit for free if you build a box.
4. Designed to last forever.
It's easy to service wherever you are with basic hand tools. It's all mechanical and most seals are re-usable o-rings instead of single use flat seals.
5. It's short enough
I've done a fair bit of wheeling in 4x4 trucks. This truck is very tall but it's short enough to take down fire roads and many 4x4 trails. Get anything longer and the only place you can explore is the desert. At the offroad park I was able to do the easiest trails and I believe I could have done some black diamonds with spotting.
6. Cab over Engine Design
This helps a bunch with overall length. You can not build a loft over the cab but you do get a pretty big bed based on the size of the truck.
7. Diesel
I want to do international travel and I would like to run WVO. So I'm going with a single fuel source.

Why not a Unimog
- very under powered engine
- needs high speed gears and turbo as well
- very expensive base vehicle
- floppy twisty frame requires articulated sub frame
- getting parts in the USA may be hard but I hear there are locals that can get you anything.
- With portal axles I believe they have 19" of ground clearance
maybe some day when I have much more money to start from.

 

[coachgeo]

1. We all love the looks of the truck and you can buy them for basically a buck a pound which is amazing. .....

Excellent write up. Kudo's to you for taking the time to write the piece.

 

[simp5782]

1. We all love the looks of the truck and you can buy them for basically a buck a pound which is amazing.

2. If you have money and little mechanical skill you can buy a refurbished truck which will save you a pile of searching for parts and becoming an expert at each sub system.
Things you must check/change post purchase:
- drive shaft "hinge out angle"
- change tranmission to ATF
- change all fluids. Get oil analysis started
- likely replace the batteries (all four of them 6tl)
- Make sure alternator is powering batteries
- Make CTIS work (fix leaks replace controller/solenoids as necessary)

A list of things that may go bad:
- anything rubber is going bad so that means, coolant lines, axle seals, hydraulic seals, bulbs
- batteries
- rubber issolators
- tires

3. tires/wheels
you have a choice of basically two tires. the 46 and the 53. They are offroad tires and you can only buy the surplus. They are very reasonably priced and there are no alternatives AFAIK. Likely remove the run flat element.

4. Engine Tuning
This is a polarizing topic. Cat actually did a great job of tuning from the factory but if you can keep it cool enough you can sqweeze more power out. There is an updated turbo. Beyond that you can do methanol/water injection, bypass oil filter, wrap the intercooler lines, wrap the exhaust, add additional oil coolers. If you don't mind shortening the engine life you could mess with propane injection. Once you do get the engine too hot you will destroy the rings and piston liner which is not replaceable. The block will need to removed and re-bored. If you want the best engine possible cat a very new truck with the cat C7 in it. Since the focus of the project is the house portion I would leave performance tuning to last.

5. high speed gears
Yes do it. Finding them is near impossible. The 3.07 ratio is good but people have mentioned if a 2.90 ratio existed it would be better because these motors have limited RPM and produce massive torque at lower RPMs. The tires are not really rated for high speeds so no matter how many modifications you make I'm certain you won't want to be driving 80 mph in the truck. Of note the A1 trucks do have ABS.

6. When you need help
If you tell people you have all "all american" truck with Cat motor they will want to work on it. The local Cat dealer can do the engine but I'm not sure what else. I did have the drive shafts built at a local shop and installed at another. One of those shops mentioned a couple showed up with a Unimog and they turned them away because they knew nothing about mogs and can not source parts for them. BTW I live in San Jose California. Not a small town. If you get the 3116 it's all mechanical. You set and forget it and then just do regular adjustments. Other motors require a laptop and cat software. No one does anything to the transmission except change fluid. If it goes bad chances are you will swap it with another working one.

7. All parts on the truck have a NSN. With effort you can find the civilian part number. Once you have that you can hunt for the part. Some things are salvage/used and others are new old stock with some small consumables being still in production. For example the cab tilts. There is a hydraulic latch. The seals go bad. There are people refurbishing them and selling them or repair for a core. You would never find that civilian part. But the engine oil filters are new and any lines or hoses can be found new. The truck much to my surprise is just another large commercial truck. I get my bolts at home depot as grade 8.8. Any hydraulics shop can make hoses for it. All the fluids are very standard and common to find. There are a lot of surplus parts and with some effort you can get anything you need so far.

8. Chemical Agent Resistant Coating (CARC)
It's like spray in bed liner. It's very tough and doesn't fade or crack. You can get replacement paints. You would be best off getting modern CARC mixed the color you like and painting over the truck instead of strip and paint. The reason for this is the truck is galvanized to avoid rust and any paint removal that works on CARC will take that off. If you really feel strongly then look at "dustless blasting" it's a wet sand blasting technique that is cheap and avoids inhaling the CARC.

Personally I have taken my truck offroading and drug it along some manzanita and oak trees which would typically scratch the paint badly and it did nothing. It did leave green marks which I power washed off. The paint is amazing and you should keep it.


-----
Why a LMTV over a unimog, pinzgaur, g-wagen, F-350, Sportster, Fuzio etc.

1. Cheap truck
2. Very capable off road out of the box.
22" of ground clearance. Giant tires which are bead locked and CTIS. Does not have a locker and you can't get them. Can get detroit style for rear.
3. Total capacity.
5 tons in bed on road. 2.5 off road recommended (from what I am told). The bed weighs 1200 lbs so you get a bit for free if you build a box.
4. Designed to last forever.
It's easy to service wherever you are with basic hand tools. It's all mechanical and most seals are re-usable o-rings instead of single use flat seals.
5. It's short enough
I've done a fair bit of wheeling in 4x4 trucks. This truck is very tall but it's short enough to take down fire roads and many 4x4 trails. Get anything longer and the only place you can explore is the desert. At the offroad park I was able to do the easiest trails and I believe I could have done some black diamonds with spotting.
6. Cab over Engine Design
This helps a bunch with overall length. You can not build a loft over the cab but you do get a pretty big bed based on the size of the truck.
7. Diesel
I want to do international travel and I would like to run WVO. So I'm going with a single fuel source.

Why not a Unimog
- very under powered engine
- needs high speed gears and turbo as well
- very expensive base vehicle
- floppy twisty frame requires articulated sub frame
- getting parts in the USA may be hard but I hear there are locals that can get you anything.
- With portal axles I believe they have 19" of ground clearance
maybe some day when I have much more money to start from.

You have lots of tire and wheel choices if you aren't picky on strictly being military. The military type tires can also be bought new for not as much as you would think directly from Goodyear or Michelin. . You have 395s, 14.00s,16.00s in 20in wheels.

You also have 12R22.5,13R22.5,12R24,11R24.5,12R24.5,13R24.5 tires and wheels available. And modifying the CTIS wheel valves is easy for those wheels.

Goodyear MVTs are rated to 81mph, some XZL setups are rated for 77mph with the large bore valve stems and all of the larger wheel tires are high speed rated.

If you are paying $1 per pound for an lmtv you are overpaying by about $10,000. Or more.

Most bearings and air brake parts are available commercially since that is a cross the board industry standard. Alot of the goofy things aren't comparable commercially like the older m809 and 939 trucks.

Sent from my SM-G965U using Tapatalk

 

[REDee]

@aernan - thank you SO MUCH - this is very helpful!!!

Let me digest this - maybe the most helpful thing I’ve come across here!