What size bolts do I need to do a TC drop of 3/4"?

Would a tc drop help me or do I need to install shims? Also which option would be more affective for me in the long run?

I have a 99 xj with a 2" xj bastard pack and 1 1/2" lift shackles and zj coils with 2" spacers. It drives great until it requires some power to go up a hill. Then it has a little vibration that gets worse the longer you climb without letting up on the throttle. Once letting up on the throttle the vibration goes away until you apply more throttle. At slow and steady speeds the vibration is not present.

 

It sounds like you need a t-case drop

I think the bolts are 10mm. You can just pull one of them and take it to NAPA and tell them you need it 1" longer. They will size it for you and make sure you have the right one.

Your t-case crossmember has 2 bolts and 2 studs.

 

i'd start by checking your tranny mount. you could simply just crawl under and use either a pry bar or just your muscle and push up on the tail stock of your t-case to see if there is excessive movement/play in your tranny mount.
there should be a little, but not a lot.
while you're under there, check your driveshaft u-joints.

 

you really should do both the axle shims and the tc drop. The yoke of the rear diff needs to be parallel to the tc output shaft to prevent vibes and ujoint wear when using a standard driveshaft. So if the tc drop rotates the output down 3*, install a 3* shim at the rear axle.

 

Thanks guys. I still need to know the size of the bolts I would need. I am disabled and have no way to remove the bolts to see what size they are. I would like to purchase the correct bolts before I take it to my friend who is going to install them for me tonight. If a purchase them ahead of time I could same him some time.

Could I replace the studs with bolts, and just have all 4 the same or do I have to replace the studs with studs?

 

Yes, you can replace the studs with bolts.

 

yes you can (and should) replace the studs with bolts.

I believe the ones you need are M10-1.5x50mm long. Grade 8 if you can find them.

Most kits come with bolts though...or are you going home-brew method?

 

Home brew is a good phrase for it. The M10-1.5x50mm would be sufficient for the 3/4" drop? If so its off to the hardware store for grade 8's.

 

50mm is about 2", so yes. What are you using for spacers?

 

For the long run wouldn't a SYE and a longer DS be the best route?

Tcase stays in factory location, you don't lose center clearance, and it solves vibration issues.

 

yes, but it's much more expensive. The fact that he did a small 2" budget boost says he'll likely be fine with just a TC drop.

 

I am using 3/4" square steel stock. I think rough country makes something similar using 1" stock.