I took my Jeep into a shop for regearing, a locker, and an SYE. The jeep currently has about 4.5 inches of lift with a T/C drop from the previous owner. I was under the impression that installing an SYE would eliminate this drop so I could get back some of my clearance, but the shop doing the work said if we take out the TC drop I will get some vibrations because the driveshaft is so short. My rear end is an Ford 8.8 and its a '90 YJ. Does this make sense? Thanks

With an SYE you should be able to ditch the TC drop. I'm running a RE 4.5 that sits over five in the back and I'm fine with just the SYE. It was perfectly smooth when it was fresh. What vibes I have now are due to wheels missing metal chunks and weights not the driveline. (pesky rocks!)

I doubt that the pinion on your 8.8 is any longer than on my low pinion Waggy 44, so I would expect we have similiar driveline lengths.

Worst case, if you do have vibes and the shop insists the TC drop is the fix, it will be real easy to stick in because all the bolts will be fresh from them taking it out. :D

Im SOA on my 90 YJ so i sit about 5.5-6" and i have a SYE with no T-case drop and stock wheelbase and i dont have any big virbration problems.

As long as you go CV shaft you'll be fine

I have 3" springs SUA on the rear with no t-case drop, no SYE, and no shims at the axle
I have some small vibrations which i believe the 1" lift motor mounts from MORE will correct


A friend of mine is SOA with 2" lift springs, SYE, CV driveshaft,
AND he tucked his belly flat for clearance

so basically the shop doesn't know what they are talking about when it comes to vibrations

Ro, they may just be wanting to stick with the TC drop so they can use the stock shaft, Id recommend getting a new CV shaft built to go with the new SYE.

on an xj with 3.5 inch lift would i need an sye or even have to drop the t/c?

I had a spring over with the RE 1.5" springs and a sye on my 231, no tc drop, and didn't have any problems.

If this is a tj, then the shop is correct, additionally, the angle on the stock drive line is oo much, so the tc drop helps that. if you want to remove the tc drop, plan to get a little bit longer cv style driveline, clock the pinion to point at the tc and you should not experience any vibrations from the driveline. if you continue to use the stock driveline, you might over extend it while in max droop. adjust the pinion using adjustable upper and lower control arms.

if this is leaf sprung, I think everything applies except use wedges to adjust the pinion angle.

hth

ken

If this is a tj, then the shop is correct, additionally, the angle on the stock drive line is oo much, so the tc drop helps that. if you want to remove the tc drop, plan to get a little bit longer cv style driveline, clock the pinion to point at the tc and you should not experience any vibrations from the driveline. if you continue to use the stock driveline, you might over extend it while in max droop. adjust the pinion using adjustable upper and lower control arms.

if this is leaf sprung, I think everything applies except use wedges to adjust the pinion angle.

hth

ken
How do these guys with belly tuck skid plates do it then? Are they getting a bit of vibration by not using the TC drop? As far as I know, they are using a CV shaft with the SYE. Just seems like a waste of money for the SYE if I still have that gay assed transfer case drop.

I don't think the transfer case drop will be needed if you replace your rear drive shaft (maybe front too... kinda depends on leaf spring sag) Tom Woods and Hi Angle make awesome drive shafts... Might be a good idea to get rid of the stocker if you plan on wheeling hard as they are made pretty light duty.