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Compatible transmissions for the M35a3 with the cat 3116

Ferroequinologist

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I really wish someone would actually do this swap so that we could all learn from it and remove a little of the uncertainty from the equation. :beer:
Someone has always got to go first! If no one ever stepped up and put some money down on an idea, that may not work or like he hoped, we'd all be living in straw huts with no electricity.

I say pick one and get started! It sounds like your mind is made up for the diff change over to 4.90's.
 
748
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Location
Woodstock, GA
Someone has always got to go first! If no one ever stepped up and put some money down on an idea, that may not work or like he hoped, we'd all be living in straw huts with no electricity.

I say pick one and get started! It sounds like your mind is made up for the diff change over to 4.90's.
My mind is 99% made up. In order for the plan to proceed though I have to Bobb my truck first. Right now my weekends are occupied with football so it will probably be winter/spring before I can start this process. The A3 is my tailgate vehicle so I can't take it out of commission until football season is over. :3dAngus:

Between now and then, if someone else performs the transmission swap then I may reconsider based on their outcome. :popcorn:
 

Hooper

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My mind is 99% made up. In order for the plan to proceed though I have to Bobb my truck first. Right now my weekends are occupied with football so it will probably be winter/spring before I can start this process. The A3 is my tailgate vehicle so I can't take it out of commission until football season is over. :3dAngus:

Between now and then, if someone else performs the transmission swap then I may reconsider based on their outcome. :popcorn:

How about just putting the 395's on and turning up the power on the Cat? My A3 has developed a slight slip going from 3rd to 4th but for all the previous mentioned post I think I am going to rebuild it to stock specs.
 
748
5
18
Location
Woodstock, GA
How about just putting the 395's on and turning up the power on the Cat? My A3 has developed a slight slip going from 3rd to 4th but for all the previous mentioned post I think I am going to rebuild it to stock specs.
The 395's would not provide that much extra speed when upgrading from the 14.5R20's.
 

m-35tom

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new flywheel $200, used trans $200, good used clutch $100??, linkage etc from an A2 $100 do it yourself $000

of course you can spend as much as you like to maybe $4000, still a valuable upgrade for a truck that should be worth 4 to 5 times as much.
 

nmdata

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I am running the equations on a different transmission configuration, 60mph with the engine rpm at 1950, the 5th gear od ratio would be 3.577:1. taking the standard 37" tire footprint. from what i have read, the engines optimal efficiency range is between 1900 and 2000 rpm, so at 60mph the 5th gear ratio would have to be 3.577:1, for a 42" tire at 60mph running 1950rpm, the ratio would have to be 4.061:1 .

does anyone else have the math to figure this out and verify for me? also has anyone found shop that can make the change? this would be something that should bring the fuel economy up to approximately 18mpg, therefore increasing your range on a 50gal tank to 900 miles. according to my calculations, ideally it would be 23mpg but i also am figuring an increased load on the engine and therefore slightly more fuel use. so the 18mpg is a compromise. this is also figured for running singles on the rear.

give me some input on this guys.
thanks in advance
 
748
5
18
Location
Woodstock, GA
I am running the equations on a different transmission configuration, 60mph with the engine rpm at 1950, the 5th gear od ratio would be 3.577:1. taking the standard 37" tire footprint. from what i have read, the engines optimal efficiency range is between 1900 and 2000 rpm, so at 60mph the 5th gear ratio would have to be 3.577:1, for a 42" tire at 60mph running 1950rpm, the ratio would have to be 4.061:1 .

does anyone else have the math to figure this out and verify for me? also has anyone found shop that can make the change? this would be something that should bring the fuel economy up to approximately 18mpg, therefore increasing your range on a 50gal tank to 900 miles. according to my calculations, ideally it would be 23mpg but i also am figuring an increased load on the engine and therefore slightly more fuel use. so the 18mpg is a compromise. this is also figured for running singles on the rear.

give me some input on this guys.
thanks in advance
nmdata,

You just posted this same question in another thread http://www.steelsoldiers.com/showthread.php?94511-drive-axel-gear-ratio-2.html#post1229173 and without any more information than you have provided people will not be able to help. I would suggest that you delete this duplicate post and provide more information in the other thread that you started.
 
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m-35tom

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I am running the equations on a different transmission configuration, 60mph with the engine rpm at 1950, the 5th gear od ratio would be 3.577:1. taking the standard 37" tire footprint. from what i have read, the engines optimal efficiency range is between 1900 and 2000 rpm, so at 60mph the 5th gear ratio would have to be 3.577:1, for a 42" tire at 60mph running 1950rpm, the ratio would have to be 4.061:1 .

does anyone else have the math to figure this out and verify for me? also has anyone found shop that can make the change? this would be something that should bring the fuel economy up to approximately 18mpg, therefore increasing your range on a 50gal tank to 900 miles. according to my calculations, ideally it would be 23mpg but i also am figuring an increased load on the engine and therefore slightly more fuel use. so the 18mpg is a compromise. this is also figured for running singles on the rear.

give me some input on this guys.
thanks in advance

if you add overdrive and then use it to go faster your fuel mpg will stay the same. the only way you will improve mpg is to add some od and then drive even slower. also the size of the tire has nothing to do with the final drive ratio which is simply the trans ratio times the rear ratio = ? the ratios you state are way off.

tom
 

Flat Black

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you guys are killing me with this thread, seriously....

ruining the MV hobby by traveling fast on a highway?

tires only rated at 55 mph and a deuce is not "made" to go over 65 mph?

Where does this **** come from?

Maybe I spent too many years on pirate where people actually build all kinds of cool custom creations that work and they understand mechanics and suspension geometry and that ANYTHING can be done, often easier and simpler than what is thought and the people who say that it cant be done frequently have **** thrown in their face by the guy who just went into his garage and did it!

If you want to talk to someone who KNOWS what they are talking about, pick up the phone and call Steve Gerstner at Differential Engineering or Randy Ouverson at OEM. These guys KNOW gears and axles and what their limits are and what you can do with them and cant do with them. I properly built and maintained Rockwell axle will cruise down the hwy at 70 MPH just as easily as it will cruise at 55 mph... The axle doesnt know any difference. Call Steve and Randy and tell me I am wrong.

A 2.5 ton Rockwell is "stressed to it's limits" under the front of a stock deuce? It's conservatively rated at 11,000 to 12,000 pounds. Go weigh the front end of a STOCK deuce on a calibrated scale and tell me that even with a winch and bigger tires and so on that the FRONT END of a deuce weighs anywhere near 12,000 pounds.

Enough said.... Now, the rock crawling world has been using deuce axles for years to do all kinds of crazy stuff... This means 800 horsepower tube buggies with 46-54" tires racing up hills bouncing off trees and literally flying through the air... I would be shocked to see much break on a stock axle with that bag of **** multi-fuel engine making a whopping 160 hp or whatever it is.... Want bigger tires and more speed and more power and better MPG and more lift and better articulation and better traction off road and lockers and better drivability and hydraulic power steering and pinion brakes that work right and on and on and on??? ITS ALL BEEN DONE BEFORE!!! And it's been done over and over and over again.... you guys need to pull your head out of the sand and get with the times... There are people on here that make me wonder why they even bought a deuce? They dont even understand the most basic concepts of a truck like gear ratios, tires sizes, diesel engine mods, what a locker is, why you cant have a 4.90 in the rear and a 6.71 in the front and why drum brakes suck ass and why you dont want a direct drive transmission or a motor on the rev limiter all day and all kinds of other weird, crazy, zany **** I have read on here. This stuff is all online and has literally been posted hundreds of times. If you dont know how to do rpm versus gear versus tire size calculations, go look it up. Don't come on here and post a bunch of crap and ask someone to hold your hand and explain it to you...You are reading and posting in the deuce modification and hot rod sub forum, so the "assumption" is that you want to make your deuce better. Go read and educate yourself. Everything has been done and posted a million times.

Tires may be rated at 55 MPH, but if you know anything about commercial tire ratings you will know that there is a HUGE safety margin in there and that load and speed ratings are typically rated TOGETHER... So this means if a tire is rated at 5000 pounds and 55 MPH, then you can go put 10,000 pounds on EACH axle and go 55 mph forever and the tires will be ok as long as they are in good condition (no cuts, not dry rotted, etc).... How many people here run their deuce down the road at 30,000 pounds for hours on end, raise your hands??

No one does that, so get the 55 mph tire rating out of your head, its absolutely baseless and ridiculous. Start a thread if you want on how many people have had a blow out traveling down the hwy in their deuce due to 60-65 mph speed, it wont have many posts I can just about guarantee it...

The problem with speed on a deuce is that you are polishing a turd. Plain and simple. You have a motor that is a dog. Swap a 300 - 400 hp Cummins, Powerstroke or Duramax from a modern one ton truck into your deuce and you would have no trouble doing 65-80 mph down the highway. An Allison 1000 and the Dodge/NVG 47 and 48 series transmissions can be built to hold over 1000 HP. These are one ton truck transmissions guys with aftermarket parts that anyone can buy. Same goes for a ZF6 or an NV4500 or even swapping something like an 8406 Eaton behind a ISB Cummins. Its all been done before. Newer and better tech than your 50 year old whatever, I can guarantee it...

You want 4.90 gear sets to go faster or get your RPM down? Call Randy and get a set, they are bad ass. Will your 160 hp turd motor push a 13,000 pound deuce on 46's down the road with a 4.90 gear set? Sure it will, just not very well... It is a system of mods and you have to integrate everything to work together. Are you willing to spend $4000 on gears so you can go 60 instead of 55? If so, knock yourself out, but I might be inclined to get an 6406 out of a wrecking yard for $500 and swap that in and save myself a few grand. Or better yet get a better motor or a more powerful one. Just dont get too crazy, you may just "explode" your fragile deuce with all that extra power.

These trucks were built to be very simple and very reliable and to be driven and worked on by 18 year old snot nosed kids that just graduated high school... It is now 2012 and technology has improved by leaps and bounds in every field of trucking and automotive engineering.... You should talk to the people who know what they are talking about, people that have done it, people that build axles for rock buggies and 1500 hp mud trucks and people that run 60" rice and cane tires... those are the guys who know where the limits are and where to spend the money... You will NOT break these parts on your modded deuce. If you want to go faster, drop RPM, have better street-ability or whatever it is that you are after, there is a proven way to accomplish it and make your deuce whatever you want.

If you are a purist and you want to only see a 45 mph truck painted original colours with ten NDT tires on stock wheels with the original CARC, etc... STAY OUT of the hot rodding forums... or at least dont come in here and bash on people who want something else. There is no reason to drive 45 mph, there is no reason to use NDT tires when better treads have been available for years, there is no reason to put CARC on a restored truck (it was sprayed by the military so that chemicals could be easily cleansed from equipment, not an issue you are likely to deal with) and there is certainly no reason to have things like stock drum brakes, non OD transmissions and the like. If YOU want these on YOUR truck, knock yourself out. If someone else doesnt like them and wants to step into the 21st century with the rest of us, who are you to tell them they are crazy or they are ruining "the hobby" or other such ridiculous non-sense?

Finally a 3116 motor as with most things made by CAT is a raging piece of ****... They are expensive to work on, can be hard to find parts for (many are dealer only) and CAT is now out of the on-road diesel market so this may get worse in coming years. There are SO many more engines that would be a better choice than this thing. It does have an SAE2 bellhousing pattern so if you are inclined to swap it, any MDT engine will bolt up to the stock transmission and you will not need an adapter. Getting rid of the motor or getting rid of the motor and trans would be a much better solution than keeping a ****ty motor and swapping out a decent transmission IMO, but as I said before, not everyone likes the same things and everyone has their own opinions.

That's my three cents for the day, i'm outta here.....
 
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Chief_919

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The point people have is that in order to make a deuce safe to drive at 70mph a whole lot of other mods are needed, not just a change in gearing.

The brakes, tires, steering, and more all need to be updated.

There is absolutely nothing wrong with pointing this out when discussing going faster.

Your comment about the tires, especially the A3 tires as this subject is about, show you are pretty clueless about them. A3 tire blowouts and failures are a very common problem, in fact in stock A3's still in military service I have had experience with a good number in my fleet, and they were kept under 55. We have had numerous people on this forum who have had A3 tires blow out on them.

Just one example: http://www.steelsoldiers.com/showthread.php?71720-Deuce-Blown-Michelin-Fun


And yes, people who don't do it right are a threat to our hobby. If you have not been paying attention some states are already regulating our vehicles off the highway, and yahoos going way too fast in a vehicle not designed to it who get into accidents just give the people who want our vehicles off the highway more ammunition
 
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Flat Black

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just because those tires suck doesnt mean than you should drive 55 mph or that other tires cant go safely over that speed.... I don't know about A3 tires because I don't have one and never will. The "dont go over 55" crowd is not limited to this model or this thread by any means.

They are funny looking little creatures and have CAT motors in them :razz:

Firestone had huge issues with tires blowing out on Explorers years ago. That doesnt mean that you should not buy an Explorer or that all Firestone tires were junk...

ABC tire found on A3 trucks is known to blow out even when properly maintained. Ok, thanks, will make sure not to use those tires. Done.

If your steering sucks, it sucks... Its a 30-50 year old truck... Its like people who put steering stabilisers on a lifted truck so it feels better going down the road... Its only a band-aid. You wont convince me that a steering system operates fine at 55 mph but somehow does not operate well or safely at 65 mph. Steering is steering and if the system is in good shape it should be fine for any speed. If its worn or out of alignment or whatever, then it should be fixed immediately. Driving 45 because your steering is old or worn out or whatever is just like the tire thing above IMO and neither are rocket science.
 
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748
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Woodstock, GA
I agree with a lot of what Flat Black says, especially about the deuce modification and hot rodding forum. If I was a purist then I wouldn't even read this sub forum and I certainly wouldn't make negative comments in it or try to dissuade someone from making a modification. Not sure what the comments about the multi fuel were since this thread is about compatible transmissions for the m35A3 with the Cat 3116. Also, I have been quite satisfied with my Cat.

To Cheif_919's point, I certainly agree that caution should be exercised and when people discuss modifications, safety should always be paramount (especially the safety of the general public). However, I think the comments Flat Black was referring to were the ones like "What are you trying to do, ruin this hobby?" or something to that effect. Those kind of sentiments are not helpful or productive. Sure, people should express legitimate safety concerns but there are more tactful and effective ways of getting that message across. The phrase "You catch more flies with honey than vinegar" comes to mind.

Just my 2cents for what it is worth.
 
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trukhead

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you guys are killing me with this thread, seriously....

ruining the MV hobby by traveling fast on a highway?

tires only rated at 55 mph and a deuce is not "made" to go over 65 mph?

Where does this **** come from?...



...Finally a 3116 motor as with most things made by CAT is a raging piece of ****...

That's my three cents for the day, i'm outta here.....
It was amusing reading you armchair pontifications. I am glad you don't ever intend to own one of them "raging" whatevers.

A fact about the tires on the A3: They have a n 80 PSI rating and they have never been inflated to that level while mounted on an A3. The CTIS has a max inflation of 45 PSI and it goes down to 13 PSI for emergency. The point is these tires have been run at half inflation since new at best and are likely internally damaged and subject to failure after 15-20 years of purposed misuse. The rims on the A3 are rated for a max inflation of 60 PSI as well.

It is true this is a free country and one is free to do as one wishes and spend enough money to polish all the the turds one wishes.

MV continue to have a target on them, there are factions that want them off the road. Note the M151 and the HMMWV. Hundreds of them will be cutup for in my opinion, good and bad reasons. Mostly they get in civi hands and civis mess up and no more 151s and HMMWV for the public.

It is when someone does all that modding to a green MV, they assume responsibility for the safety of the design and when it fails and, or is involved or causes in an accident and that reflects on all of the other owners of green MVs.

So go pimp your ride, do whatever, it's a free country.:D
 

goodguyzy

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I think flat black is missing the point, one of the big problems is the low top end speed of an A3 (45-50). The result is a truck that is dangerous to drive on the interstate. RIP shooting iron. A top speed of 55-60 would be much safer This thread was started to resolve this issues not make a truck that will go 70. This doesn't mean that there are not other issues to resolve including tires that are prone to blow outs. There are a bunch other comments that are wrong so learn your stuff before you put in your 3 cents because I value any comments as long as they are educated.
 

73m819

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I think flat black is missing the point, one of the big problems is the low top end speed of an A3 (45-50). The result is a truck that is dangerous to drive on the interstate. RIP shooting iron. A top speed of 55-60 would be much safer This thread was started to resolve this issues not make a truck that will go 70. This doesn't mean that there are not other issues to resolve including tires that are prone to blow outs. There are a bunch other comments that are wrong so learn your stuff before you put in your 3 cents because I value any comments as long as they are educated.

" Maybe I spent too many years on pirate" quote by flat black, this may be the reason for his 3 cents.

Doing ANY SPEED on the interstate is unsafe, you can be doing 90 and still get taged by someone. Because people CANNOT pay attention because of texting, on the phone, scratching there noise, ect, ect. is no reason to make these trucks do what they are not designed or meant to do. I run on the interstate all time, if I am going to get taged I would rather be in a big truck rather then a little honda, SHOOTING IRON paid the price because someone was not paying attention and going fast NOT because he was doing 50. it would have happened if he was going 60, you CAN NOT out run stupid. On the other hand if a set up truck runs over soccer mom and her kids, the news WILL LOVE it, "a go fast old army truck going FASTER THEN DESIGNED and MEANT to go, KILLS mom and kids" this WILL be real good for the hobby, where it is getting harder and harder to register these trucks, just ONE GO FAST event could be the straw that breaks the camel's back the keeps our trucks from being "on road trucks"

If someone wants to go faster then what the trucks design calls for, let them buy a newer civi truck and put army truck sheet metal on it.
 
748
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Woodstock, GA
" Maybe I spent too many years on pirate" quote by flat black, this may be the reason for his 3 cents.

Doing ANY SPEED on the interstate is unsafe, you can be doing 90 and still get taged by someone. Because people CANNOT pay attention because of texting, on the phone, scratching there noise, ect, ect. is no reason to make these trucks do what they are not designed or meant to do. I run on the interstate all time, if I am going to get taged I would rather be in a big truck rather then a little honda, SHOOTING IRON paid the price because someone was not paying attention and going fast NOT because he was doing 50. it would have happened if he was going 60, you CAN NOT out run stupid. On the other hand if a set up truck runs over soccer mom and her kids, the news WILL LOVE it, "a go fast old army truck going FASTER THEN DESIGNED and MEANT to go, KILLS mom and kids" this WILL be real good for the hobby, where it is getting harder and harder to register these trucks, just ONE GO FAST event could be the straw that breaks the camel's back the keeps our trucks from being "on road trucks"

If someone wants to go faster then what the trucks design calls for, let them buy a newer civi truck and put army truck sheet metal on it.
Ron, your point is quite valid and has been received. Agreed, the truck (in this case the M35A3) may have been originally "designed" for 48 mph. That speed is probably fine and dandy in the convoy setting that the truck had in its military life. I mean, the "designed" engine and transmission combination only give roughly 48-50 mph at 2,700 rpm. In civilian ownership, I agree with the other posters that this speed is more of a danger than anything else because for the most part, we don't travel in convoys and are therefore a hazard to ourselves and others while traveling at that incredibly slow speed (even on a lot of surface streets). This thread is in the "deuce modification and hot rodding" section and that is exactly the topic we are discussing here (in this case, modifying a M35A3 to actually make it safer/better). If anyone cares to place so much weight on technologies that are (in the case of my truck) over 20 years old. Kudos to you but I think that better things have come about in that time. Respectfully, I and many folks on this site are more than capable of designing systems that are better than their original design of 20-45 years ago. By your train of logic, if someone were considering installing dual circuit brakes on a M35A2, you would probably say "no that isn't part of the original design. Why are you trying to ruin this hobby?". As I have done here, I would make the opposite case that a newer, better, safer design is out there and should be pursued without persecution.
 
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