T98 Identification

Definitely rebuild the 18 as it's probably due anyway, but if the problem persists look at the rear driveline/U-Joint angles and make sure the yoke are in phase. If they are off the vibrations created can transmit through the transfer case into the transmission with the same symptoms you describe. Will usually happen at "float" conditions when you aren't compression slowing or under acceleration but when the gears aren't under load. Will sound like a rattle, in fourth gear, and will sound like the tranny is trying to come apart if severe.

 

I wanted to post an update on my gearbox project. As several people said above, the transmission was not the problem. The D18 1 1/4" intermediate shaft was pretty worn - the needle bearings had worked into the shaft and worn it away quite a bit. Luckily, this problem did not appear to damage the gears.

I solved the problem with a Novak rebuild kit. I did the whole case instead of just the intermediate shaft, as I don’t want to have to remove it again anytime soon to fix something else. Reinstalling it was a real adventure: I have a transmission jack adaptor, but it sticks up so high that it wouldn’t fit under the JEEP – even though it was on stands. So, I ended up digging a trench under it, lining the trench with a board, and rolling the jack with the D18 on it under there. Long day.R) Anyway, it worked and now I have a functioning transfer case installed.

I do have two more questions now though. When the D18 is in rear wheel drive only, the front output still spins. The front clutch shaft is not actually engaged when I have it in rear wheel drive, but appears to be tightly coupled to the main shaft. I’m guessing it is that new output bushing? Without removing the case, is there anything I can or should do? Does it matter? I figure it will loosen up with use, but I don’t want to damage anything in the front axle by having the front propeller shaft spinning with hubs unlocked.

My other question is this: the transfer case-mounted emergency brake wobbles and is a bit tight (the brakes, that is). It seems to be loosening up a bit as I run it, but it isn’t quite straight on the shaft. I did my best to put in on there flush, but is there some other way to “balance” this unit so it will not vibrate?:?