Humvee transmission

[Doug D.]

Looking to change my 3 speed in my hummer to a 4 speed OD. Can anyone tell me what i need an where to buy it? Is there one place that i can get it all? Transmission can be used. I have a car lift that my hummer will fit on and wondering how much trouble it will be to change. Thinking about buying a transmission jack to help. Sorry for multiple questions but any help is appreciated.

 

[Mogman]

Have you read through the sticky near the top of this forum?

Lots of Questions about 4L80E Swaps

Seems like a lot of people have questions about transmission swapping, so I'll refresh the link to my write-up on the topic. Maybe make it a sticky? http://g503.com/forums/viewtopic.php?f=63&t=221765&p=1305053&hilit=4l80#p1305053 Augi

www.steelsoldiers.com

 

[MarkM]

If I were to replace my 3 speed with a 4 speed I personally would go with a built 700R4 as it is a mechanical transmission and not have to worry about electronics at all. When built the old 700R4 can easily handle the HMMWVs power.

I do have experience with the 700R4s at the drag strips and they are a great transmission. The ONLY road block is obtaining a TV cable bracket that will bolt onto the 6.2 or 6 5. They can be had from a GM/GMC 4x4 van with those engines and are very hard to come by. There are a number of threads for this project. I have one in case I do the swap. Just my .02 cents.

Mark

 

[TOBASH]

I went 765R4 in my M1025. Works awesome.

I prefer my M1165 with 4L80E, BUT there is that tranny electrical stuff. It has a turbo so it has more power. It also has a tranny electrical issue that a 700R4 is immune to.

 

[Retiredwarhorses]

Here we go….R4 transmission is Garbage. if it was so great? Why was it Mfg discontinued so quickl? Why is the 4L80e still being produced? And the 4L85e. Talk to companies that actually do these conversions, as well as good transmission shops.

 

[MarkM]

The 700R4 is not garbage but hey thanks for the shot.

 

[patracy]

Cleaned up this thread. Any more attacks and points will be issued.

As to the 700r4 no longer being made, that's absolutely true. The 4l60e took it's place. But if you really want to split hairs, the 4l80e hasn't been newly produced in a decade as well. A 700r4 could live behind a 6.2 or 6.5, with enough money. A 4l80e will live behind one no problem and stock. The 700r4 alleviates electronics, the 4l80e requires it unless you do a full manual VB.

Simply put, it's going to cost you one way or another to gain an overdrive. Either mechanically with a lot of upgrades. Or with the additional cost of electronics.

That's purely my opinion on it. I've owned from a 200-4r up to a Allison in GM vehicles.

 

[Retiredwarhorses]

Cleaned up this thread. Any more attacks and points will be issued.

As to the 700r4 no longer being made, that's absolutely true. The 4l60e took it's place. But if you really want to split hairs, the 4l80e hasn't been newly produced in a decade as well. A 700r4 could live behind a 6.2 or 6.5, with enough money. A 4l80e will live behind one no problem and stock. The 700r4 alleviates electronics, the 4l80e requires it unless you do a full manual VB.

Simply put, it's going to cost you one way or another to gain an overdrive. Either mechanically with a lot of upgrades. Or with the additional cost of electronics.

That's purely my opinion on it. I've owned from a 200-4r up to a Allison in GM vehicles.

the 4L80e or 85 is still mfg’d by GTP “General Transmission Products , a wholly owned subsidiary of AM General.

 

[FlameRed]

I am a newbie so my knowledge is from the experienced forum members here.

I was able to do the swap on my back with a proper hydraulic tranny jack. The sucker is heavy with the transfer case attached so make sure you have something capable of lifting that beast.

I found the 4L80E plentiful as many folks are doing Allison/Cummings swaps. At the advice of others, I found one that did not look like a junk yard rust bucket. Got most things as a package, so look for:

• A clean 4L80e and transfer case
• Both front and rear drive shafts that came with the 4L80e
• The torque converter cover plate for the 4L80e
• The crossmember for the 4L80/gearbox.
• I was able to use the shift linkages for the tranny and gear box that was supplied.

New Stuff:

• New carrier bearings for the front drive shaft
• New or rebuilt Torque converter
• New filter and fluid of course.
• I used the US Shift Quick 4 with remote display, and their harness
  • You will need to relocate the existing Throttle position sensor on the throttle body and install one for the controller. This was the worse part.
• You will need a 4 speed shifter with Park position
• I had to replace the starter and flexplate as the teeth were all chewed.
• I replaced the exhaust at the same time as it was so rusty and disintegrated trying to take it off.
• Some of the U-Joints on the drive shafts were bad so I replaced the questionable ones.
• Check your rear main seal while you are in there. Mine was ok.
• Lots of grade 8 hardware instead of reusing rusty junk.
• I replaced the fuel tank as I found it was leaking. Made the install easier.
• I needed the safety plate that goes between the rear drive shaft and the fuel tank.
• I could not get the old mechanical speedo working so I just replaced it with a GPS one.

Remember, get as much used stuff used as you can in the package as just about everything on these beasts seems to be about $1k with the HMMWV tax!

Good luck!

 

[Bulldogger]

I had someone else do the swap, for a 4L80 and NP242 from a turbo diesel setup. Used EZ TCU for the controller to avoid having to replace the wiring harnesses. There's several places that will sell you a salvaged HMMWV 4L80 and they are easy to rebuild (I'm told). I'm having mine replaced due to a hopefully unrelated failure next week, sourced locally from another SS member. There are several ways to go depending on you personal preference and local availability of parts.