I know... I'm only suggesting a guy can get there without having to spend two thousand bucks on a new housing.

It's worth mentioning, Dynatrac's solution is good only for guys with existing Dana 44s; owners of Dana 30 front ends can't reuse their internals for this "budget" solution.

 

Does anyone know if this has happened in earlier model jeeps or any other vehicles with new driveshaft, gears etc. I know the the numbers are few, but I dont think these are isolated incidents.

 

I'm sure it has happened in the past, but there wasn't the instant feed-back then, as we have now.

 

i'm worried now too. don't need to have a 2k part failure like everyone else here. why not have the knuckles cut and turned to give better pinion angle?? seems like this would be the cheapest solution but i haven't heard too many people doing this yet.

 

That would be a solution. People lean toward not doing it, though. And, not everyone finds out they should have. It takes just the right combination of things to explode the T-case.

 

Monte, what's your current caster? (And was this verified via an alignment?)

If you're near factory spec, I don't think you need to worry...

 

So...I hate to beat a dead horse....I had an alignment done after I installed my lift. They never said anything to me about the caster whether or not it was bad....of course I doubt they would. But you're saying that as long as it's close to factory that we shouldn't have to worry? I know there are a lot of factors though. And no I'm not going to come back and point fingers and say you told me it was fine if it breaks...no worries in that department. I do plan on upgrading things as I go though, so I'm sure over time I won't have to worry about it as much.

This thread has been really good btw. I've been getting a lot of info and thanks again to everyone.

 

When I’ve seen these threads in the past I always assumed it was the rear (loaded) part of the transfer case that exploded, not the front (unloaded) part of the case. Is this always the case - the front explodes? Seems odd as it’s not loaded when driving down the freeway.

If so, is the assumption that the front was weakened from wheeling (or just by manufacturing defects), and the vibrations at high speed broke it apart, or is it simply the unloaded vibrations at high speed break it apart?

 

These are the facts as I see them.

• We don't have any known reports of exploding t-cases on stock JKs. Maybe it's happened. We've got 35,000+ registered members here, so I presume if stock JKs were busting their t-cases, we would have heard about it by now.
• Many/most of the exploding t-cases we do know of are in JKs which have been modified in a similar way, e.g. lift kits, bigger tires, increased caster angles via adjustable front CAs, etc.
• The prevailing opinion on JK-F has held 6-7 degrees caster as optimal after the installation of lift kit and tires; the genesis of this line of thought may or may not be the Oct. '07 write-up on the DIY JK front end alignment.
• It's my position -based on a finite amount of experience with altered caster angles/test drives/two alignments in the last 12 months- that running as much as 50% or more caster than factory spec (4.5 degrees) is the cause of these failed t-cases. At the very least, there is a strong relationship between the two.
• It's also my position that driving your JK with 7 degrees caster is more hazardous to your JK's health than less caster is to yours. (Said another way, we have JKs with a lot of caster breaking t-cases, but we don't see anyone with low caster driving into the ditch.)

A front end alignment is 70 bucks. For all the money we spend on our hobby, why not invest this paltry sum to have toe, caster and axle centering set with precision? Why rely on a tape measure and dial indicator?

Have caster set to 4.0-4.5 degrees.

Drive it for a week.

If you come back here and report evil handling or uber-darty steering that you simply cannot live with, I'll publicly go on record and invite people to ignore everything I've stated here.

 

i just went out to check my t case after reading these threads.

when i moved the drive shaft up and down to check for play, i noticed that there is a good deal of transfer case/transmission movement due to the rubber mounts. this caused me to wonder how drive line vibration could impact the cases so severely. if it was rigid mount maybe i could see it. i am not saying vibration couldn't cause the failure but i think the dampening/absorptive effect of the mounts is worth consideration.

one other thing i think is worth considering is slip travel of the drive shaft. if there is not enough compressed travel of the drive shaft, with the front suspension at full droop the shaft would transfer massive forces to the cases.


back in the day i had a full size GMC truck with 42" super swampers and a 454 with a dana 44 font. (i broke axle shafts constantly). the truck had 8" lift and the front drive shaft angle was so severe i had to grind the double cardan for clearance. in deep mud, i flogged this beast like a free whore. improper pinion angles would be an understatement yet no problems in the gears set, drive line, or transfer case.

it just makes me wonder how this t-case can be so sensitive to vibration in spite of rubber mounts and if possibly drive shaft travel could be a source of trouble