Humvee 5.9 allsion conversiin

[Humvee5.9?]

Putting a 5.9 24v with a allison 1000 in a humvee m998 I have everything mocked up but am worried about drive shaft angles. Front shaft is good but rear is 1.5 inches higher and 1.5 right of the diff any advise would be great thanks

 

[MrMarty51]

Just guessing here, seems the angles would be all right. A person would need to get the specs from Spicer or some U-joint company to figure what the maximum angles are.
The reason a U-Joint needs an angle is to keep the rollers spinning and turning within the trunnions, a little more angle would increase that action. That is what is used to keep the U-Joints from wearing grooves in the cross and within the trunnions.

 

[Husker6.5]

See how much you can get the pinion rotated up (if at all) and the tail shaft down so that you are as close to being in line as possible. One plane of deflection being a little severe isn't nearly as bad as having two. Angles of deflection being within the U-joint manufactures' specs, like @MrMarty51 mentioned, is very important for the longevity and mechanical integrity of the assembly, especially since you will be applying considerably more torque and stress to the drivetrain than stock. I can't believe that your centerline with an inline-6 is that far off of the V8 it's replacing, and you should be able to hopefully drop the transmission's tail down some, too. The closer you can get those angles back to stock, the better. I understand that the driveshaft is shorter because of the longer drivetrain, and that automatically makes the vertical angles sharper. But, for every two degrees of angle you decrease in front by lowering the entire drivetrain, you also do the same to the rear joint. And the shaft gets shorter, too.

 

[Will L.]

There is no adjusting differential positioning or angles. Hmmwv/ hummer diffs are mounted solid in the crossmembers.

I’ve no idea on proper Engine placement to stuff the other engine in place of the 6.2/6.5.
But it is so much taller/longer that I would be amazed if it could fit the bellhousing in the same spot.

 

[Husker6.5]

I thought that possibly the differential could be shimmed or wedged on its frame mount to adjust the angle.

Never been deep enough into an HMMWV to really know the mechanical ins and outs. Now, quarter tons and CUCV's. . .

I fully realize that the 5.9 drivetrain is a beast in every dimension compared to what it's replacing, nor the dimensional limitations/mechanical restrictions of the bay it's being dropped into. I was pretty much just stating the general rules of powertrain alignment - whether vehicular or stationary power transmission - the less deflection in multiple planes, the better. And a couple of three ways to achieve that via pinion angle, drivetrain height and driveline centerline. I'm totally in awe of people who stuff them into places they were never designed to be.