M1009 Transmission options question: TH400 vs 700R4

[rsh4364]

M1009
6.2 with turbo
4L80e tranny
NP208 with slip yoke eliminator
Dana 60 and 14bolt with 4.56 gears
37" hummer tires and wheels
13mpg in town
16 mpg on the highway at 70-75 mph.

That's pretty respectable,but I want 20 mpg minimum.

 

[MarcusOReallyus]

I do not need nor want overdrive in my truck.

Spoken by someone with 3.08's and not 4.56's

Yeah, a GV OD is on my wish list.

 

[cucvrus]

What is the equal gear ratios to the OD unit? Does it make it like 4:10's , 3:73's? Just asking for some comparison. As I have had K30 trucks with TH400 and these gears. I am asking for some comparisons.

 

[ODFever]

Tinman - If your truck is running at peak efficiency, 20 MPG is average. Not bad for a 30 year old 5200 lb military truck! Since you sold both of your other vehicles and bought the CUCV, I suggest stashing cash away in case you have mechanical issues or if you have to run out and buy another vehicle. Putting all of your transportation requirements on your CUCV leaves you with few options if something really bad happens.

I have a 1999 Crown Vic Police Interceptor as my second daily driver. I just got my CUCV back from my mechanic last night. I had him replace the fuel filter and the transmission vacuum valve. I have so little time to work on my truck these days. I drove my CVPI to work instead. This morning, I drove my CUCV. It runs great and shifts perfectly. The two hours I spent on labor were well worth it (I supplied the parts).

 

[Drock]

What is the equal gear ratios to the OD unit? Does it make it like 4:10's , 3:73's? Just asking for some comparison. As I have had K30 trucks with TH400 and these gears. I am asking for some comparisons.

I'm guna throw this out there. These trucks are not power houses. Buy going to a taller gear ,sure it'll drive better on the highway . But 1st & 2nd gear would be ah pig. And virtually useless as an off road vehicle at that point. They mite be fine if they were 500HP monsters but 165HP just isn't much to work with.

 

[Skinny]

I think if you are trying to squeeze more fuel economy out of it I would suggest some 31" all terrain tires and an NV4500 swap. You simply are going to lose efficiency putting power through a poorly geared, non-lockup, power robbing transmission. Of course for the money you will spend on that, it may just make more sense to buy a used Civic or Corolla that gets 40mpg all day long.

Labor of love! My M1031 gets 13.5mpg on a good day but it certainly gets more SPM (smiles per mile) than driving the Subaru to work.

 

[cucvrus]

I'm guna through this out there. These trucks are not power houses. Buy going to a taller gear ,sure it'll drive better on the highway . But 1st & 2nd gear would be ah pig. And virtually useless as an off road vehicle at that point. They mite be fine if they were 500HP monsters but 165HP just isn't much to work with.

Thats not an answer to my question. I am asking what the trade off is? If you put the 700R in an M1028 does it make it RPM wise while cruising like a truck with the 3:73 gears and the TH400 or like a TH400 with 4:10 gears? I am asking because I had/have all 3 with the same K30 6.2 diesel 4 x 4. The only difference I ever noticed was the high RPM's in the CUCV verses the mild RPM's in the 2 other civi trucks w/o 4:56 gears. And amazingly the fuel consumption was about the same. I may be wrong but I think that all the K30 trucks had the J code 6.2 diesel. The ones I had do/did. And all 3 plowed snow about as equal. Heck the M1009 plows snow really well with the 3:08 gears. Just a question. No opinions. Just a question for comparision. And what does an NV4500 swap cost?

 

[86M10086.2L]

Keep in mind the $1500+ your going to spend now trying to get better fuel economy is going to take years for you to actually see any benefit. If you were driving a rig cross country, all the time, this would make more sense. In that circumstance small gains make a big difference. On a local daily driver or a second vehicle toy not so much. Many people talk about overdrives, turbos and manual tranny swaps etc... all these even in the best scenario might net you 1-3 mpg benefit. It takes a whole lot of time, and quite a few miles to reap the benefits of the mods. none of this it going to turn your truck into a pseudo Honda Civic. Tune it up right, keep your right foot in check and leave it alone. Mod it for your needs later if necessary.

 

[cucvrus]

I agree. I would rather spend the money on something else. This is a no real return on modifications that don't need done. I was just asking because I never saw anything different about any of the plow trucks that I have used. I would NOT spend extra cash to change something for that small gain. The M1009 blazer plows snow just as well as the M1028. The M1009 can not carry a salt spreader but it does a good job at all the other work tasks. And like I said in the past they are excellent vehicles for what they were intended for and other then that its guess work. I am fortunate enough that I don't have to drive one day in and day out as an every day every occassion vehicle. And that I am very thankful for. They are not for hauling aging family members in and making them or myself comfortable. They are like a tool it is useful when used for the applacation it was intended for and useless on other occasions. I would not drive one in a funeral or wedding. So the long of the short of it is I strongly agree with OD fever & M10086.2L. No change is needed. It is not worth the cash needed to do the change. And the TM would be void after the changes were made. Remember the TM's that is all I ever read on this site. Look at the TM's. It's an opinion thing again and I have that right. It is mine.

 

[Skinny]

I would not drive one in a funeral or wedding.

I wouldn't get married to someone that didn't understand why I wanted to show up to the wedding in an MV. I definitely plan on getting buried in mine.

I'm not sure I follow you with the TMs being void. These rigs are 30 years old, lots of hands have been in the pot at this point

 

[cucvrus]

It's not me getting married. It's my children and younger relatives. Been there done that years ago. Still happily married. Wife don't drive CUCV's would if she had to but don't have to. I have more respect for her then that. Like you say 30 years old not exactly up to modern comfort level. When I was younger and serving they were great but after 30 + years the new truck is king. Not to discount the CUCV. It is just not a fit all vehicle. Remember an opinion thing. I would rather spend 12 hours traveling in a modern car / truck then 3 hours in any CUCV on the highway. Been there and done that. Many many times coast to coast several times. I still drive several CUCV's everyday. But do not want them as my only personal daily drivers. It may not make sense in that statement but I have a purpose for each vehicle. Long distance is not the use for the old CUCV's anymore. I love them to pieces but not enough to have them as an only vehicle. The sound and comfort level is just not there. When I was younger OK. But since having new vehicles I seem to choose them for the long haul. I am a die hard CUCV guy but I do have limitations. Admit it. If you had a choose between a 30 year old truck to drive or a new truck. In all honesty you would drive the new truck on trips and for business. OK maybe not. Sorry it is my opinion again. I do have a fear of parking lots in my new truck. Never have it in my CUCV. Get my point. Have fun in everything you do and do it the way you want to do it. Respect others opinions and be open to hear theirs. And remember the TM's become more useless with every modification you do. Stay safe.

 

[MarcusOReallyus]

Of course for the money you will spend on that, it may just make more sense to buy a used Civic or Corolla that gets 40mpg all day long.

Bingo. There is a certain amount of sow's ear, silk purse factor to be considered. It is what it is, and an econobox ain't what it is.

 

[Tinman84]

So at this point I'm thinking it doesn't make sense to do the transmission swap or the turbo.

Of course for the money you will spend on that, it may just make more sense to buy a used Civic or Corolla that gets 40mpg all day long.

Labor of love! My M1031 gets 13.5mpg on a good day but it certainly gets more SPM (smiles per mile) than driving the Subaru to work.

And I definitely agree about the smiles per mile. I bought the CUCV knowing that for better or worse it would be an attention getter, and thus far it has been by far for the better. I've had kids look up as it rolls down the street and holler "Cool!" or "I like your truck!" and I've had opportunities to talk to lots of vets that have memories of driving or working on them when they were serving. Took it deer hunting and it crawled through places some other rigs couldn't get even with 4x4 because of the short wheelbase and tight turning radius. As frustrating as it has sometimes been to find yet another thing that needs some TLC, I'm loving having it, and I bought it knowing it would be a running project (in both senses).

Thanks again for the input guys. This is exactly what I was looking for.

 

[ODFever]

I have never been to Oregon, so I don't know what the summer temperatures are. The summers here in sunny Florida are steamy to say the least. 95+ degrees with 90% + humidity. I had factory A/C installed in my CUCV to make it more bearable to drive. I also installed an insulation blanket under the hood to quiet the engine a bit, and make it easier to start when the temperature drops into the 20's (yes, that does happen in Central Florida). I posted pictures in this thread, post #828. http://www.steelsoldiers.com/showth...-done-to-your-CUCV-today-lately-Part-2/page21
Put your extra green into modifications that will improve the comfort factor of your CUCV.

 

[llong66]

Hi!, I don't mean to steel a thread, but I am tossing around the idea of a 700R4 swap and am a little unclear of the lockup clutch ppl talk about on the TQ. Can someone either explain this or point me to a good thread or article explaining it? Not a kit for doing so, but exactly what it is/does?

Thanks,
Greg

 

[Iceman3005]

Inside the torque convertor is a clutch, when pressure is applied to it, usually this only happens after 4th gear or overdrive has been engaged, the torque convertor clutch engages so it can't slip anymore, so the torque convertor, input shaft, and output shaft are now locked together, so the torque convertor can no longer slip. Basically it becomes like a manual transmission at that point. All vehicles after 1987 had this kind of torque convertor. A lock up switch can also be added to force it to lock-up torque convertor clutch in second and third gear, means no slipping of the torque convertor so now 100% of the power is going straight to the wheels, just like a manual transmission. Any 700r4's that I install for my customers, I install a relay switch on the brake light switch so when the brake is pressed it activates the relay and turns OFF the lock-up mode, so the torque convertor isn't pushing the truck.

 

[Iceman3005]

I have have done countless 700r4 transmissions, as for your M1009 the overdrive doesn't help much, to low of an rpm in overdrive. But the first gear helps a lot, it is a 3.06 to 1, verses the turbo 400's 2.48 to 1, that lower gear is great for getting the truck moving easier with less power, plus when pulling heavy loads. The 700r4 basic swap what I charge is about 1500, for a full blown monster trans that can take 1000hp it is $2800, verses the gear venders which is about $3500 plus another $500 in parts not supplied, and making the drive shaft short, etc., plus the turbo 400 is only rated up to 350hp. Not that the cucv could come close to that, but why spend $4000 on a bolt on overdrive when for $2800 you could have a trans that can take 1000hp and not have all that extra length, wiring, computer, switches, like the gear venders.

 

[Csm Davis]

I will also put my two cents in about a Gear Vendors. Don't waste your money I had one in a custom 84 dually and it was great right up until it failed and even though I had it installed at the factory and paid through the nose to have them build a new 3 piece driveshaft. They tried to not replace it and it had less than 10,000 miles on the unit, this was not just my experience but many of the people that I have talked to that had one.

 

[Tinman84]

We'll get temps in the triple digits but with much less humidity than that for a couple weeks in the summer, and anywhere from 85 to high 90s regularly from June through August, so AC is nice. I have a couple things that are farther up the list for the moment, but I may try an AC install eventually. I'll probably look into that insulation blanket sooner rather than later because the winter temps here can get into the single digits or negatives in January and February.
If anyone has been to Oregon and thinks that my description sounds funny, I'm in eastern Oregon, the hotter, colder, drier, and (in my opinion) better side of the state.

 

[Recovry4x4]

What is the equal gear ratios to the OD unit? Does it make it like 4:10's , 3:73's? Just asking for some comparison. As I have had K30 trucks with TH400 and these gears. I am asking for some comparisons.

Putting a 700R4 in a CUCV with the normal 4.56 gears and 235/85R16 tires will net you 1859 RPM @55MPH and 2197 @ 65MPH

To achieve the same RPM with the TH400 in place, you would need a gear ratio right in the 3.00 range. For armchair comparisons, roughly the same final drive RPM as the M1009. The 3.06 first gear is just wonderful for getting the anemic 6.2 moving a heavy truck in a decent fashion. In my opinion, the 700R4 is the perfect compliment to the 6.2 as it was designed.