Drop Tcase without shimming?

I've looked through the threads before this, but haven't seen anyone who's dropped the transfer case (after a lift) but not used shims as well. I'm still wrapping my head around the geometry of it, but it seems to me that would reduce the angle pretty well.

Basically just need a fix for winter and then get the SYE in the spring. But my mechanical ability is limited, and I'm not sure I'll be up to installing the shims.

specs on lift and year?

If you can install a t-case drop, you can install shims.

Basically you unbolt the u-bolts after purchasing new ones, and put the shim in (thick side facing backwards) under the leaf springs.

Install new u-bolts and torque to spec.

i've got a tcase drop on my 01 and didn't shim the rear. its the RE3.5" superflex kit.. the rear pinion angle isn't that great, but it did reduce the vibes a lot. but yeah you should probably be fine running just a tcase drop for a while until you get an sye. thats what im doing and its been fine on and offroad, although i am hearing some clunking noises im pretty sure are coming from the driveline that i can't figure out.

gijosiahh said:

i've got a tcase drop on my 01 and didn't shim the rear. its the RE3.5" superflex kit.. the rear pinion angle isn't that great, but it did reduce the vibes a lot. but yeah you should probably be fine running just a tcase drop for a while until you get an sye. thats what im doing and its been fine on and offroad, although i am hearing some clunking noises im pretty sure are coming from the driveline that i can't figure out.

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is it like a grinding when you let off of the gas?

yeah when i let off as well as when i push the gas...but its more distinctive when i let off. i thought it was driveshaft ujoints but i replaced them and its still doing it so im not sure what it is.

the grinding sound was on my 98 till i did a sye and new shaft i think its that the teeth on the end of the shaft are barely hitting the output shaft from the tcase

yeah that would make sense. an sye is definitely on my to do list...when i get the money of course. what sye did you end up running?

gijosiahh said:

yeah when i let off as well as when i push the gas...but its more distinctive when i let off. i thought it was driveshaft ujoints but i replaced them and its still doing it so im not sure what it is.

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its probably the driveshaft binding on the t-case yoke. my 94 with a 4.5" RE lift does the same thing but only when i hit the brakes really hard or get the jeep airborne...

Thanks all and sorry, it's a 98 Cherokee sport 4wd 4door. Just had installed RE 3.5" super-ride with leafs.

I've read that there can be problems with shims, they break, fall out, and somehow affect and reduce lubrication? And I've got both that vibration at low speeds as well as the thunk when letting off the gas.

I guess I can do the Tcase drop today, and then next day off do the shims, then wait out the winter.

Thanks for all the help.


See you all soon in the 'I think I broke my Tcase' thread. [/sheepish]

Shims only affect lubrication (or have the possibility to) if you are tipping your pinion angle UP (when you get an SYE) because its tougher to get enough fluid in the diff when the fill plug is angled towards the ground

you are wanting to push your pinion down a bit. if you didnt use any extended shackles with this kit, your pinion is probably pretty close, you might only need 2* shims. the TC drop will help more than the shims will.

I would suggest getting a crossmember with a TC drop "built in" - Rusty makes a nice one....I think there might be a few others...

the reason i say this is, if you say your mechanical abilities are limited, when you put a 1" spacer between your crossmember and frame rails, you'll have to do something about the mounting studs on the rails - each side of the crosmember is held up by a bolt that threads into the frame rail, and a nut that goes on a stud that protrudes from the frame rail.

I'm trying to explain this the best I can...

the problem is, the stud that protrudes from the frame rail is MAYBE an inch long, so when you put a 1" spacer over it, you wont have any way to thread the nut on. having a crossmember with the drop built into it is better b/c it just mounts up the same way the stock one does.

luckyorwhat said:

I've looked through the threads before this, but haven't seen anyone who's dropped the transfer case (after a lift) but not used shims as well. I'm still wrapping my head around the geometry of it, but it seems to me that would reduce the angle pretty well.

Basically just need a fix for winter and then get the SYE in the spring. But my mechanical ability is limited, and I'm not sure I'll be up to installing the shims.

Click to expand...

I'm too much of a novice and too much on the steep part of the learning curve to give advice, but I am capable of making an appeal to authority. I recently asked Dirk at DPG this same question. He said the application for the shim was only when you have an SYE/double cardon. With the SY and single cardon, you don't shim. Now I was discussing this issue in the context of a 2 inch budget boost, maybe I would have gotten a different answer if proposing something different, but I do believe I've also seen a diagram somewhere that shows that with the single cardan, the output shaft and pinion should be parallel.

gijosiahh said:

yeah that would make sense. an sye is definitely on my to do list...when i get the money of course. what sye did you end up running?

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i ended up with a AA and tom woods combo from rustys, it was like $480 + shippin, there are less expensive combos out there though

Thanks again all, gettin 'er done. Git 'er done!

Rod I think I saw that too, this one? http://www.4x4wire.com/toyota/tech/driveline/

luckyorwhat said:

Thanks again all, gettin 'er done. Git 'er done!

Rod I think I saw that too, this one? http://www.4x4wire.com/toyota/tech/driveline/

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No, not that one, but one that shows the same concept. I think its in Zappe's book on building up the XJ. I could swear I've seen it in one of htese threads too.

When I lifted my 93 to around 4" I had issues with output yoke making contact with the driveshaft Ujoint ears as the shaft rotated. A TC drop did help, but I added 3* of shim on the rear axle to ease up the angles on the yoke and driveshaft.

It the shim also pushed the yoke back into the TC a little more and i liked that was well.

So I used the shim not so much to improve drivetrain angles as to improve the angle at the Slip yoke and Driveshaft.

Just for a second, if you were to pretend you were talking to a guy who'd suffered brain damage of some sort, how would you explain how to install the TC drop kit?

http://www.rubiconexpress.com/Products.aspx?Pn=1911&Vid=FD40413792331

I'm just going to put a jack under the crossmember, loosen the bolts, insert the new ones with spacers (spacers between the body and the member), and tighten it up? The transmission isn't going to be bothered by this then, it's got a flexible attachment to the engine?

...Yes I'm asking for instructions on the simplest part kit available. lol

Well it's not that easy. The stock cross member uses a stud with a nut and a bolt on each side. You have to remove the nut, then remove the stud. In the past I have done it this way:

Spray the nuts and bolts with PB blaster penertrating spray every other day for a coupel of days before the install. Spray up into the unibody so that the blaster falls on the inside where the stud and bolts are.

Put a jack under the center of the cross member. Remove the nut and the bolt from each side. Slowly lower the cross member. The Engine is mounted to the unibody via the motor mounts an dthe trans is attached to the cross member. Once you lower it, the weight will be on the motor mounts. Once lowered, you can put the jack under the trans and just lift it a little to support it.

On each stud, place a hardened 10mm 1.50 pictch nut with a lock washer between the two. With a wrench on the top nut, tighten the bottom one up to the top one. Once that's done, put the wrench on the top nut and start to loosen it lefty loosey. It will usually fight a bit, but it will eventually come out.

Once out, you slide the TC drop bracket between the cross member and the unibody. Then put the provided longer 10mm bolts through the bracket and tighten it up. You may have to use a screwdriver in to the hole to pull the cross member in alignment with the holes. DO NOT stick the screwdriver into the threads, just rest it in the very start of the opening.

I put a 1 inch t-case spacer in when I lifted to 2" because I was afraid of driveline vibes. Then I went to 3" and now to 4.5" and still no problems. No shims, no SYE, just the $30 t-case spacers. I guess I should probably get a SYE eventually but I figure if it ain't broke...

Oh yeah, 96' XJ Country, 4 door, 4" rear MJ springs, 4.5" front thunderbird coils.

MoparManiac said:

(thick side facing backwards) .

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I'm pretty sure you're statment is backwards. Just a thought.