2.5" lift

[mattyj]

Hence my question. I'm well aware that XJ TC crossmembers are all the same... Someone else posted that it wasn't a question of angles, but of support. I thought they meant support for the TC in general and that it was manifesting itself in vibes at the output shaft, which is where the crossmember comment came from.

It is a question of support and angles. The transfer case output shaft on later models is not supported as well as earlier models because of a different, shorter, transfer case tail cone design.

If it isn't a question of angles, then how did dropping the T-case fix the output shaft problems? I fail to see how dropping the t-case down does anything to increase the strength of any involved parts, unless by doing so you alleviate stress that was there (still not increasing the stregth, but at least longevity/durability)..

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The idea with lowering the transfer case in to reduce the angle of drive line operation & therefor reduce the amount of angle that the front unijoint has to work through. Then reducing the amount of load the output shaft has to work with.

What I think I'm hearing from people right now is that there was a problem with the support of the output shaft (undersized bearings?) and that the fix was to do NOTHING to address the actual design, and was to MOVE the transfer case, with the same shaft/bearing/tailcone problems...

You are right, by lowering the TC case it doesnt fix the actual design (which remember, doesnt cause a problem untill you start messing with the suspension height), but it does alieviate some drive line angles.

I'm not trying to be difficult, just trying to learn more, can someone please explain how this works out as a fix if the original problem had nothing to with angles?

To fix this sitiuation correctly to suit our lifted needs, you need to split the angle the front uni joint has to wok through by installing a double carden drive shaft(two front unijoints) that work together to reduce the angle put on 1 single joint. Also by installing a SYE you reduce the lenght of the output shaft of the TC which helps also.

 

[Archdukeferdinand]

To fix this sitiuation correctly to suit our lifted needs, you need to split the angle the front uni joint has to wok through by installing a double carden drive shaft(two front unijoints) that work together to reduce the angle put on 1 single joint. Also by installing a SYE you reduce the lenght of the output shaft of the TC which helps also.

I understand that, I'm trying to figure out how a factory T-case drop was a fix for the output shaft problems of STOCK 2000 Xjs...

 

[XJTony]

Ive got a 97 (the new design ) and researching the same issues other people are concerned about.....but I keep reading the same thing from people with older Jeeps ....we need the input from people with the newer models ....that have experienced the issue first hand ...common guys we know your out there give us the low down !!!!

 

[Archdukeferdinand]

You are right, by lowering the TC case it doesnt fix the actual design (which remember, doesnt cause a problem untill you start messing with the suspension height), but it does alieviate some drive line angles.

According to a couple of people on this site (no reason to disbelieve them) it DID cause a problem at STOCK suspension height on the 2000 model year XJs, and so the XJs started coming FROM THE FACTORY with a t-case drop.

I could buy the decreased angle on front DS decreasing load the output shaft deals with being the reason for a T-case drop FROM THE FACTORY, but it still seems like an awfully bandaid-ish way of dealing with the problem... (and would refute the post claiming that the factory drop was not angle related).

Is there anyone out there who can explain to me why 2000 model year XJS suddenly needed dropped t-cases at STOCK suspension height? Now I'm really intrigued.



EDIT: And another thing, why would the front DS be the problem on the HP 30? My understanding is that the high pinion allows for a fair amount of freedom in lift height without causing angles that bind the DS or tilt the pinion shaft/diff too far... (don't know about those angles relative stresses on the t-case output), more freedom than the disconnect 30s according to some...

 

[crabhab]

I am running a RE budget boost on my 99 sport and I got vibes on deacceleration. Not enough to worry about though. Might wanna try some small axle shims. Maybe 2000 + Xj's needed tcase drops due to the low pinion D30 that they started using that year. I had a brand new 2000 Xj without Tcase drop though.

 

[MrShaft696]

ive lifted and lowered quite a few rides and there is no definite anwser to the vibration question, it is most likely that you will have a problem but there are a bunch of other people that tell you they didnt have any issues. Take it one step at a time. If you do the lift and it vibrates, drop the transfer case & shim the pinion angle. You can shim the tc with washers first to see if it works, if not live with it or go to a sye. Your not out of the water completly with the sye, that has to be set up correctly too.