Homebrew transfer case drop questions

Is there any kind of formula for how far to drop the transfer case? I only chose 1" as it seems to be the most popular size. But I have seen drops of .75". 1", 1.5", 2" etc.... Obviously I would like to keep it as small as possible without having to go thru alot of trial and error so I thought 1" seemed like a happy medium.

I have a rough country 3" lift on a 99 XJ. The leaf springs and fairly flat even with the add a leaf so Im not getting the full 3" lift in the rear, but would like to make sure my transfer case drop is signifcant enough for when I replace them with a new 3" spring packs.

I bought 2 inch long bolts. Im going to be using 1/2 inch nuts as spacers for the actual drop. Does anyone think that would cause a problem with stress distribution vs a length of aluminum or steel stock? I did see a drop kit on ebay that used what looked to be round poly pucks similar in setup to my using nuts.

why do you want to drop it? are you getting any vibes?

I believe I am.I do have vibes but not entirely sure whats causing it. It hards to tell as I never drove the jeep without the lift to have anythign to compare it to. If the drop doesnt appear to have any positive effects then I can always take it back off.

ok. i was just wondering.

i homemade mine out of 2"x2" sqaure tubing, like 1/4" thick or something like that. it cured my vibrations for a couple years, but now they are back again. im going to be getting a slip yoke eliminator from Advanced Adapters soon. at first i had the same setup your talking about doing, but it looked scary to me so thats why i went with the square tubing.

I temp used washers (1 inch worth) as a drop kit in mine. Didn't look good, but worked and never had any issues with it. Had them in there for 8 months and changed it to a block setup.

95XJ-93 said:

I temp used washers (1 inch worth) as a drop kit in mine. Didn't look good, but worked and never had any issues with it. Had them in there for 8 months and changed it to a block setup.

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That is basically what they RE spacers are that I used on my first lift. Only difference was the RE ones are round aluminum spacers, rather then washers.

I would go with washers rather then nuts.

1" is fairly good just make sure to check the condition of the threads or you can run into trouble later on down the road. when i installed my lift it came with the 1" sleeved rubber spacers and like three months later i was out campin/wheelin and on the ride out down the fsr i had this thumping that got progressivly worse so i got out and the crossmember (driverside) had torn itself out of the nutserts however i drove another 8km out of the bush and 20-30km to the nearest lordco and did said washer stacked spacer that probly lastest another three months till i was out wheelin tossed it in 4wheel and the added torque tore them out again resulting in me needing to bandaid weld it till i got home pulled the seat and went through above and ran some monster bolts through

Well, chances are you do need a t-case drop, especially since it's a 96+. However, since it sounds like you're new to this Jeep, you should check all the regular maintenance stuff first, U-joints, bearings, etc...
Also check your current driveshaft angles, there is a slight chance you may need to shim the rear axle.
As for the drop itself, I agree nuts may not be the best idea here. Solid spacers are best, but washers would be better than nuts. I used some steel spacers I found at Lowe's. They aren't too thick, but I found several that fit inside each other to beef it up some.
1" is usually the standard drop, and there are reasons for that. Keep in mind when you drop the t-case, the whole engine/tranny will move as well. This will cause binding on your motor mounts, so you don't want to go too far!

Thanks for all the input guys. I think since I already bought the hardware, I'm going to throw on the nut setup I bought. If everything seems to work out ok then I'll go ahead and buy a real drop kit, or some solid aluminum stock and build a better designed kit.

kboyts said:

Thanks for all the input guys. I think since I already bought the hardware, I'm going to throw on the nut setup I bought. If everything seems to work out ok then I'll go ahead and buy a real drop kit, or some solid aluminum stock and build a better designed kit.

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Just make sure you swap it out before you go wheeling and smack the cross member on something!

kboyts said:

Is there any kind of formula for how far to drop the transfer case? I only chose 1" as it seems to be the most popular size. But I have seen drops of .75". 1", 1.5", 2" etc.... Obviously I would like to keep it as small as possible without having to go thru alot of trial and error so I thought 1" seemed like a happy medium.

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Is there a formula? No. Don't forget though:

• As you drop the t-case, you are twisting the motor mounts and making them more prone to tearing.
• You are also moving the t-case shifter linkage and can cause shifting problems.
• The engine cooling fan is going to be a little higher than it used to be, and can cause interference with the shroud, which has remained in place on the radiator.
• The front driveshaft operating angle at the t-case inceases as the t-case is dopped.
• You just lifted the Jeep to increase ground clearance. Isn't lowering the t-case taking a big step backward at that point?

That said, I'd say 1" is about as high (or low) as you want to go. Have you read http://go.jeep-xj.info/HowtoTCdrop.htm yet?

Jim www.yuccaman.com

Im not concerned over losing ground clearance as I dont wheel the jeep. The lift was mainly for looks and so I could fit the tires. Its my daily driver.