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Shim size for 3.75 lift

bgcntry72

NAXJA Forum User
I am between 3.5 and 4 inches of lift on my 99. I have the 8.25 and AW4 and will be installing the RE SYE this weekend. Any ideas what size shims I should get before starting this job? I have a 4*, but I have a feeling I may need a 6*. Any help would save me hours of experimentation(which I am sure I will have to do anyway, because its a Jeep), and an extra set of shims. TIA
 
It all depends on the how the lift was made, AAL, new leafs, shackles, etc.

The best way is to go the hardware store and buy an angle indicator for about $10.

If you have a standard driveshaft with a slip yoke then you want the same angle on the pinion yoke as you have on the t-case output shaft. Of course you don't want exteme angles between the t-case output and d-shaft, pinion and d-shaft. If you do then an SYE is you only solution.
 
I had the same lift as you and used a 6* shim with a Chrys 8.25 axle. I also have the Tom Woods/AA HD SYE kit installed. I always wanted to try a 7 or 8* shim because 6* isn't quite enough for normal freeway 70mph + driving (Yes I could still feel some vibes).
 
Good to know. I have no drop in now and no shims and I only cavitate on decel from 40-33. The low roar sets in at 70+, which I travel often. I was going to start with the 4* and move to the 6* if necessary, but now I will start with the 6*. Thanks for the info jimbar. Anyone else?
 
With my 3.5" lift, 5sp, 8.25 axle, RE SYE; I was using 4* shims and was 2* under at the pinion. With my current 6" lift, 5spd, 8.25 axle, I'm using 6* shims now and still 2* under at the pinion...

I did have some minor rumblings on decel above the 50 mph threshold after my regearing, but it turned out to be a loosened pinion nut. Liberal amounts of lock tite cured that....

Ivan
 
Thanks for the help. I will install the shaft and see what I get. Then the 4* shim, and if need be, the 6*, which I doubt. It is surprisingly well mannered now, no shaking, just a harmonic imbalance 60-70 mph. Appreciate all who took the time to explain their experiences, you guys made this a lot easier.
 
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