HMMWV Drivetrain

[gray1027]

I have a question that not a lot of people will not like. I put a 700r4 in my first M998 a few years back and it works flawlessly. I had to get the adapter kit, flexplate, different spline input shaft for transfer case, shifter , etc. Now my question is, I have another M998 now and would like the 4 speed in it as well. I have a stock 700r4 / NP241 factory mated out of a 1990 Z71. Will that set up bolt up as is, or what will I need to change? I am a navy corpsman and not a mechanic, but play one on the weekend with lots of advise and the internet. Thanks in advance.

 

[TOBASH]

I have a question that not a lot of people will not like. I put a 700r4 in my first M998 a few years back and it works flawlessly. I had to get the adapter kit, flexplate, different spline input shaft for transfer case, shifter , etc. Now my question is, I have another M998 now and would like the 4 speed in it as well. I have a stock 700r4 / NP241 factory mated out of a 1990 Z71. Will that set up bolt up as is, or what will I need to change? I am a navy corpsman and not a mechanic, but play one on the weekend with lots of advise and the internet. Thanks in advance.

You will need to change the flex plate and the torque converter. You need a new shift and some associated levers. You will need the TV plate and cable.

Bow tie overdrives in California will have a list of what you need and will have what you need.

 

[Thumper580]

Check out this link https://transmissioncenter.net/shop/humvee-th400-to-700r4-conversion-flexplate-2/

 

[MarkM]

That tv setup is very very hard to find as it only came in a (civilian) 3/4 ton van with the 6.2 so good luck finding one.

Mark

 

[gray1027]

You will need to change the flex plate and the torque converter. You need a new shift and some associated levers. You will need the TV plate and cable.

Bow tie overdrives in California will have a list of what you need and will have what you need.

Thanks. For some reason, it already has the TV Cable Bracket on it. I have the TV cable. I have a 4 speed shifter. I just did not want to have to crank open the transfer case to swap out the input shaft again.

 

[TOBASH]

A substitute TV system is sold by bow tie overdrives.

 

[Mogman]

You will likely also need a custom modified cross member, you may have to modify the drive shafts and the TC shift pattern will probably be incorrectly marked on the OEM shifter, also you will probably not have a working speedometer unless you can crack the TC and find the correct components for a mechanical speedometer for that TC.
But of course it can be done.
IMHO the 4L60 is a great transmission for this application, much less power loss than a 4L80 and better overall gear ratios

 

[gray1027]

You will likely also need a custom modified cross member, you may have to modify the drive shafts and the TC shift pattern will probably be incorrectly marked on the OEM shifter, also you will probably not have a working speedometer unless you can crack the TC and find the correct components for a mechanical speedometer for that TC.
But of course it can be done.
IMHO the 4L60 is a great transmission for this application, much less power loss than a 4L80 and better overall gear ratios

I have the 700r4 already and just didn't want to go computerized. I don't tow anything or do real 4 wheeling. I just have a fondness for humvees from my days with the marines. I did forget about the speedo gear. The shifter I have is a old 3 speed that I put a 4 speed detent and modified. I got the info and drawing off this site back in 2019 fr the other HMMWV. It worked great.

 

[Mogman]

I have the 700r4 already and just didn't want to go computerized. I don't tow anything or do real 4 wheeling. I just have a fondness for humvees from my days with the marines. I did forget about the speedo gear. The shifter I have is a old 3 speed that I put a 4 speed detent and modified. I got the info and drawing off this site back in 2019 fr the other HMMWV. It worked great.

The TC shift pattern will be different, the NP241 is a part time TC, and can be electric or manual shift, of course you will need a driver side drop.