Hi guys,

I have a Jeep Cherokee that I'm rebuilding and am looking at transfer case optionsm, and am hoping you can answer a couple of questions for me.

Specifically, the Cherokee came with an NP231 by default, or you could get an optional NP242 factory upgrade. The 242-J is a good transfer case but there are some better models, such as the 242-HD that came with 1998+ Durango and Dakota pickup trucks, and the 242-AMG that was used on the military Humvee (it has twice the load rating of the 242-J).

I've looked around and can't seem to find a line on 242-AMG transfer cases, so I'm wondering if the H1 Hummer had the same model. Anybody know anything about these? What is the shift pattern (military 242-AMG did not have 2WD, only 4WD part-time and full-time)? What is the spline count? Does it have a rear slip yoke or a fixed yoke?

Thanks for any info!

 

the NP218 was the first t-case on the Humvee's when they were running the 3L80E or THM400 transmission.... that t-case has fixed outputs on both front and rear.

the NP242AMG is an expensive case, and has a rear output slip yolk and a front output fixed.... that t-case was installed on the 4L80E and the Allison 1000.... I don't recall the spline counts, but might be easy to cross ref the output shafts of the trans....

all of the t-cases used in production on the Humvee or Hummer H1 were all the time 4wd, with a selectable 4H (open diff between front and rear outputs), 4HL (Locked output of front and rear outputs same gearing as 4H, and 4L (different gear set and locked outputs). I used to know the actual gear ratios, but I don't anymore.... this info I believe is listed on the net both on www.humvee.net under the hummer knowledge base and www.flashoffroad.com

 

The H1 transfer case is the 242AMG. The front input splines are different than the Jeep as well as the rear output. (I don't recall the numbers either). You should be able to put a 242J input in it to get it to match your tranny. The rear output uses a common GM type slip yoke in 1330 or 1350. Front output is 1330. As mentioned, there is no 2wd mode. I think the ratio for low range is 2.72:1

The bad news is, unless you can find a used one somewhere, they cost over 3 grand new.

 

You can get a reman drivetrain from drivetrain.com for under a grand with core or 1350 without core.

I ended up buying one from there with a 3 year warranty last fall and had no problems. Turned out my old t-case only needed somewhat minor repairs so I wound up jumping the gun by buying a replacement.

At least I have a spare I guess