HMMWV 6.2L vs CUCV M108 6.2L

Hi All,
My friend has a 6.2L engine and drive train that he has taken out of a HMMWV so that
he could put in a Duramax.

My question is What are the differences between this and the M1008 Engine and drive train?
What do I have to do to make it an exact replacement for my M1008?

I would like to fix his up to put in mine so I can take mine out and rebuild it for
a spare.

This is my daily driver so the transition has to be quick and painless. ie I will have to be able to get his in to a state that can be tested before I make the swap. So yes I will have to buy additional parts.

Thanks for any help,
Bruce

Hi Bruce,

I'm sure the experts will chime in soon, but from what I remember, the engine and trans are the same, transfer case is different. The IP on the HMMWV is different, but similar and if I recall correctly, it's turned up a little bit more than the CUCV one. Also, the glow plugs on the HMMWV are 24v where the CUCV units are 12v. And of course the exhaust manifolds are vastly different, and I'm not entirely sure if the oil pan is the same or not.

That's all I can tell you... I hope it at least gets you started. Good luck!

Thanks,
Yes it does. That is one question that came up already concerning the transfer case.
We suspected it was different.
Bruce

Oh, one thing I forgot to add... the trans is similar, but not the same. the HMMWV doesn't have a park gear unlike the CUCV.

-S

The HMMV has a 24 volt IP so you'll have to either replac the pump or just swap the shutoff switchtoo. the 6.2 engine will bolt up to the TH400. just make sure the flywheels are the same as well. Also check the pulleys. some of the HMMVs are serpentine setups, ie Flywheel pulley. sender swiches, Have fun.

The oil pan is different and possibly the oil pick up as well. The intake manifold has the two screws for holding the air duct arranged side to side as opposed to front to rear on the CUCV. Since the engine blocks are the same, all of the CUCV items like pulleys and manifolds and brackets will attach. Engine mounts are different. As mentioned the Injector pump is 24volt on the Humvee, but the electrical solenoids are in the top cover which is easily swapped. Coolant crossover is different as well as any temp sensors. You will need to swap any little things like the rear coolant block off plate for he left head that holds the Glow temp sensor, but all that stuff will fit right onto the Humvee engine. The water pump should the same, but I have never compared them and measured them side by side. As previously mentioned the Turbo 400 (3L80) has no parking pall, but you can put one into fairly easily or go without. You would probably need to use the Transfer case adaptor from the CUCV, although I have never compared them side by side, I'm shure the CUCV adaptor extends farther down. The t case is different as mentioned. The Humvee uses a special type of detent cable to operate the Transmission modulator and I guess it could be left as is, because it does work well and the adjustment for it is at the left rear of the intake manifold, in the engine valley. If you just have to use the Chevy modulator, vacuum pump and plastic shift thingie up on the right side of the IP, it will all attach without opening the IP. The vacuum pump from the CUCV will replace the RPM device at the rear of the humvee engine valley. The harmonic balancer is the same, so the cucv pulleys will line up OK when mounted. All in all, it will swap easily as the engine and transmission are the same models, with some different things bolted to them.

Thank you very much!!
Do you happen to know why they decided not to keep the parking detent in the HMMWV's?
Bruce

I don't know why they left it out initially, but for the new HMMWV's (M1114,M1151,M1152,M1165) they all have the parking gear.

Thanks,
That is very usefull. I will definetely be keeping the parking gear feature.

I was told that they left out the parking pall in the transmission, because it wasen't strong enough to hold the vehicle on a steep grade at full GVW.

Is there any reason to believe that it won't hold a M1008 at full GVW?
Should I be concerned that my M1008 might fail in those conditions?

I don' think you'll have a problem with the parking pall on your CUCV. I think that the Military might have used some sort of severe test and the pall failed. Maybe they loaded three thousand lbs in the bed of the Humvee and then added a loaded M101 trailer and went to a steep ramp at one of the test tracks and it bent the pall did something else equally as paralyzing to the Humvee transmission.

That would make sense. Then someone thought about the test awhile latter and decided that they really should have the pawl in there after all.
I think this is what is refered to as Military Logic...