Transmission Opinions

[SounDrive]

I plan to do a good amount of highway driving in my M1010, so the stock TH400 isn't going to cut it. I plan on running 37" takeoffs and keeping the 4.56 gears. I will be hauling about 1500 to 2000 extra pounds of equipment in the back, but the inside of the ambulance shell is completely stripped so that cuts out a good amount of weight. My guess would be around 8500-9000 pounds curb weight (still 500-1000 lbs under GVWR), maybe even less once I cut down on weight some more.

Here are the options I'm considering, I'm leaning towards the latter 2 for the lock up torque converter. And to throw a monkey wrench into the whole equation, I may (or may not) turbo it down the road.

1. Gear vendors overdrive

2. Built 700r4 (already got a TV cable bracket lined up if I go this route)

3. 4L80e + standalone computer

Most threads I've found refer to the NP205 transfer case, will the NP208 in the m1010 change parts needed for the install?

And just to restate it, reliability is a big factor for me. I make very long drives once every couple months and don't want to get stranded several hours from home.

 

[SounDrive]

To add to this, my uncle has 2 donor trucks each with a 6bt and NV4500 - I'm sure he'd let me buy one cheap. I don't think I'm up to a motor swap myself though and I'm sure a shop would charge a ton. But if that would be my best option, I may do it.

 

[rustystud]

Your not going to find a stronger transmission then the TH400. With a "Gear Venders" overdrive that would be a killer unit. You can go with the 4L80E but it would need to be modified to reach the TH400's level of reliability, and yes I know the 4L80E is already a modified TH400. The factory units (4L80E) have several problem areas that need to be addressed for a truly dependably unit. I have a "book" of factory recalls and upgrades for this transmission alone. Just say NO to the 700R4 (4L60E) transmission. It will take almost $1000.00 of upgrades to reach the factory strength of the TH400. Also remember whenever you need to depend on a electronic module or computer for the operation of your vehicle, you just created another failure point.
This is just my opinion of course, but since I have professionally rebuilt these transmissions for the last 30 years I'd say my opinion does count for a little at least. Maybe not.

 

[SounDrive]

My main concern with the TH400 is the lack of a locking diff will cause more heat buildup and extra RPMs at cruising speeds on the highway. Maybe a trans cooler would help?

I do like that the GV unit can split gears so it won't be falling out of the powerband as much.

 

[Chaski]

That is a lot of weight to move around 24/7 with the stock 150ish horse diesel. rustystud is right that it will take money no matter what you choose, and that a gear vendors is indestructable. Personally I have a 700r4, and I spent about $1100 on just parts to build it up. I would have mixed feelings on swapping it into a rig that heavy.

Have you tried running it with the 37" tires yet? If you travels take you anywhere that has more than a 5% grade at highway speed you might not be gaining much with an overdrive since you won't have enough horsepower to pull yourself up any sort of grade at 65, even 55 may be only a dream. Going from stock sized tires to 37" ones is almost a 15% difference which is similar to going from 4.56 to 3.73 gears.



My rig weighs about 6300 empty, and when I put a cord of dry softwood firewood in it it gets up to the 9000 pound range. When it is that heavy I wish it had an underdrive not an overdrive since sometimes the right gear to grind up a hill does not exist. Empty or with a light load it is fantastic. 6.5 crate naturally aspirated, 700r4, 4.88 gears and 37" tires driving around in the rugged cascades up and down lots of grades. Just something to think about since I have no idea what the terrain or highways are like where you will be traveling. One suggestion is to make one change at a time and try it.

To answer the question about the NP208, if you were to go with a 700r4 you would have to take the case apart and swap the input shaft. If you go gear vendors or 4l80e your transfer case requires nothing.

 

[SounDrive]

That is a lot of weight to move around 24/7 with the stock 150ish horse diesel. rustystud is right that it will take money no matter what you choose, and that a gear vendors is indestructable. Personally I have a 700r4, and I spent about $1100 on just parts to build it up. I would have mixed feelings on swapping it into a rig that heavy.

Have you tried running it with the 37" tires yet? If you travels take you anywhere that has more than a 5% grade at highway speed you might not be gaining much with an overdrive since you won't have enough horsepower to pull yourself up any sort of grade at 65, even 55 may be only a dream. Going from stock sized tires to 37" ones is almost a 15% difference which is similar to going from 4.56 to 3.73 gears.



My rig weighs about 6300 empty, and when I put a cord of dry softwood firewood in it it gets up to the 9000 pound range. When it is that heavy I wish it had an underdrive not an overdrive since sometimes the right gear to grind up a hill does not exist. Empty or with a light load it is fantastic. 6.5 crate naturally aspirated, 700r4, 4.88 gears and 37" tires driving around in the rugged cascades up and down lots of grades. Just something to think about since I have no idea what the terrain or highways are like where you will be traveling. One suggestion is to make one change at a time and try it.

To answer the question about the NP208, if you were to go with a 700r4 you would have to take the case apart and swap the input shaft. If you go gear vendors or 4l80e your transfer case requires nothing.

The part in bold is another concern I have. At the minimum I will be doing a serpentine belt swap which I've heard is good for making up around 10-20hp worth of losses and making my own CAI. I've also considered a turbo or complete 6BT swap.

I won't be driving through any mountains, but depending on which direction I go we do have a fair amount of moderate hills.

 

[rustystud]

My main concern with the TH400 is the lack of a locking diff will cause more heat buildup and extra RPMs at cruising speeds on the highway. Maybe a trans cooler would help?

I do like that the GV unit can split gears so it won't be falling out of the powerband as much.

I forgot to mention that lack of horsepower of the engine, thankfully "Chaski" brought it up. In my truck even with a 383 Hi-Torque gas engine I put in I can barely maintain 55 pulling our 24ft trailer going up "Snoqualmie Pass" . I have the factory TH400 (modified of course ) and I wished I had a Gear Venders unit behind it. That way I could "split" the gears and keep my engine in it's torque band. At work at the transit dept. we have about 100 small Ford buses . They hold 16 people and when loaded the overdrive would kick-in and out until the transmission would fail. So Ford came up with a overdrive eliminator for use. So if your going to be hauling any kind of serious load I would stay away from the overdrive transmissions. The only factory overdrives that I consider to be worth their salt in a truck is the Allison or the GM 6L90E . Both of these units cost a ton of money to just buy outright. I personally plan on buying the Gear Venders unit when I can afford it.
As far as heat goes, a simple transmission oil cooler and a dash gauge to monitor the temperature is all you need. I also have a pressure gauge installed to make sure I have enough fluid and no leaks and it allows me to monitor the shift pressures.

 

[SounDrive]

I forgot to mention that lack of horsepower of the engine, thankfully "Chaski" brought it up. In my truck even with a 383 Hi-Torque gas engine I put in I can barely maintain 55 pulling our 24ft trailer going up "Snoqualmie Pass" . I have the factory TH400 (modified of course ) and I wished I had a Gear Venders unit behind it. That way I could "split" the gears and keep my engine in it's torque band. At work at the transit dept. we have about 100 small Ford buses . They hold 16 people and when loaded the overdrive would kick-in and out until the transmission would fail. So Ford came up with a overdrive eliminator for use. So if your going to be hauling any kind of serious load I would stay away from the overdrive transmissions. The only factory overdrives that I consider to be worth their salt in a truck is the Allison or the GM 6L90E . Both of these units cost a ton of money to just buy outright. I personally plan on buying the Gear Venders unit when I can afford it.
As far as heat goes, a simple transmission oil cooler and a dash gauge to monitor the temperature is all you need. I also have a pressure gauge installed to make sure I have enough fluid and no leaks and it allows me to monitor the shift pressures.

I do like the idea of not having the OD constantly swapping on/off under a load, so that's another plus for the GV and NV4500.

 

[rustystud]

I do like the idea of not having the OD constantly swapping on/off under a load, so that's another plus for the GV and NV4500.

If you like shifting then they would be great. Personally I don't like shifting anymore especially when going on a long trip or towing anything.

 

[SounDrive]

If you like shifting then they would be great. Personally I don't like shifting anymore especially when going on a long trip or towing anything.

I prefer an auto but I'm not opposed to manual if it would work better in this case. I need to look into what all a 6bt swap would entail since I could get the entire drivetrain easily. I really like the M1010 and still want to use it for my project rather than something boring like a van, but I feel like it will most likely be a dog with lots of weight and the stock 6.2.

 

[cucvrus]

The part in bold is another concern I have. At the minimum I will be doing a serpentine belt swap which I've heard is good for making up around 10-20hp worth of losses and making my own CAI.

Indeed that is bold. I have to ask how a serpentine belt will increase an engine that has 135 hp by 15-20 hp? And I am asking. I never heard of changing drive belts and getting a horsepower increase. What is a CAI? Just asking. Have a great day. Seriously. I would consider driving a newer vehicle with a 6.0 and a 6 speed automatic to do what you want to do. Driving a 30 year old M1010 on the highway is not a good move. These were not designed for a lot of highway driving. You can do it of course. But at the cost and discomfort that are not a fair trade off in my opinion. I have read here many times where guys drove long distances in the CUCV's and I have done the same. But when I bought a more modern truck. I have no comparison. I like my CUCV's as is and for what they were intended for. Anything more and I get disappointed. All around local driving and utilitarian use A 1. Highway driving and everyday as only driver IMHO never. Happy Holidays.

 

[corelokt]

I have destroyed 2 level three built 700's and two np208s. They just do not take any heavy use.
I am going to try a level 3 built 4l80 from a place on the net called Jake's. A brazed fin converter and a twin sticked NP205 to allow low range towing if needed. I am also upgrading to 1410 rear driveshaft ujoints. All this to tow 20k when needed. Powered by a navistar 6.5, with upgraded cooling, and turbo and meth.
Like said, temp and pressure gauges. Stand alone shift computer and the best trans cooler(s) you can buy.
Just say no to the 700r4, no matter what sales hype you read. Even the TV cable is way to touchy and one screw up ruins 3k of transmission.

 

[corelokt]

People who have done the Cummins swap seem to like them. Keep it simple, manual injection, no engine computer, in my opinion.

 

[Recovry4x4]

What is a level 3 trans? Is there a chart that shows levels of transmissions? I feel ignorant not knowing.

 

[Chaski]

What is a level 3 trans? Is there a chart that shows levels of transmissions? I feel ignorant not knowing.

"Level" does not mean a thing. Different transmission builders have different recipes of upgrade parts that they combine to make a transmission stronger than stock. One guy's "level 2" build might be completely different than another's "level 2"

You really have to compare what parts the builder is using.

 

[gimpyrobb]

6bt and nv5600 if you go custom, do it once.

 

[corelokt]

Look up teds transmission on the internet.

 

[corelokt]

Usually a level refers to the claimed horsepower it will handle. Each builder uses different parts or suppliers etc.

 

[SounDrive]

The part in bold is another concern I have. At the minimum I will be doing a serpentine belt swap which I've heard is good for making up around 10-20hp worth of losses and making my own CAI.

Indeed that is bold. I have to ask how a serpentine belt will increase an engine that has 135 hp by 15-20 hp? And I am asking. I never heard of changing drive belts and getting a horsepower increase. What is a CAI? Just asking. Have a great day. Seriously. I would consider driving a newer vehicle with a 6.0 and a 6 speed automatic to do what you want to do. Driving a 30 year old M1010 on the highway is not a good move. These were not designed for a lot of highway driving. You can do it of course. But at the cost and discomfort that are not a fair trade off in my opinion. I have read here many times where guys drove long distances in the CUCV's and I have done the same. But when I bought a more modern truck. I have no comparison. I like my CUCV's as is and for what they were intended for. Anything more and I get disappointed. All around local driving and utilitarian use A 1. Highway driving and everyday as only driver IMHO never. Happy Holidays.View attachment 654755

It won't be a daily driver by any means, just once per month or two for audio shows. I just don't see the need to purchase a $20-30,000 truck to tow it 6-12 times a year when it should be capable of moving itself for a lot less investment

V belts are very inefficient at transferring power to the accessories on the belt so I've seen claims that you can gain several HP to the wheels for every v belt you replace with a more efficient serpentine belt that isn't going to be slipping. I think a 10-20hp gain from eliminating all the v belts is a reasonable gain although most/all of that will be lost to the extra weight of the 37s.

CAI is cold air intake, it's not going to do a ton but opening up the stock intake to get more airflow and slightly turning up the fuel should help a decent amount.

 

[SounDrive]

People who have done the Cummins swap seem to like them. Keep it simple, manual injection, no engine computer, in my opinion.

I'm starting to think this is my best option. It will require the most fab work and time, but it's still relatively inexpensive if I do most or all of the work myself. and by far is the strongest option and probably more reliable with the weight