1" Transfer Case Drop Degree Question

On my 97, I have installed a 1" transfer case drop and was wondering, relative to stock, what does the transfer case drop yield in driveline angle?

After installing rear springs (3" lift), I have found that the rear axle pinion needs to be shimmed DOWN 2* in order to bring everything into parallel.

I do understand that every Jeep will be and is different, measerments on my driveline if i remember correctly are 5* down t-case, 17* driveshaft and 7* up on pinion angle and was wondering the best solution to combat vibration.

As becoming leary of adding a shims to the rear axle and possibly coming out from underneath the springs to perch mounts, I am looking for advice.

The shims get attached to your leaf springs with the center bolt. No need to fear them coming out.

From what I understand, the shims are installed underneath the springs and held into place by end of the bolts, yes. But with the shim wedge being greater thickness then the length of the end of the bolt, when all bolted back down to the spring perches, is there a possibility of the axle sliding or coming free of its correct mounting in relation of the springs?
The u-bolts will be torqued down holding everything together. Does axle torque or wrap come into play?
Just wondering.

Picture a shim. Now picture a square hole in its center. Now picture you lifting your leaf springs off their perch with the center pin intact. Position your shim with fat end toward the rear on the perch. Lower your leaf springs with center pin going through the square hole in the shim and coming to rest in the perch hole which guarantees proper positioning of the axle. Tighten your frigging u bolts and you are done until you have to re tighten them again, and perhaps again after driving some. Remember that your TC and your rear diff are the two items which come into play with the parallel issue...not the ground level. Your pinion and yoke angles work in conjunction with your u joints. If that angle is too severe, even if it is parallel, your u joints may be too far out of the eliptical confort zone they require and the vibration game begins.

There are center bolts with a longer head for installing shims.

Thanks Madden, I think that is the solution I am looking for. It seems that the RE center pins will not be long (deep) enough to clear the shims and rest into the round hole in the spring perch. With that length, springs, shims installed, everything should stay secure.

I have taken into consideration the angle that the driveshaft is at.
That is why I asked the origional question about what degree of drop the 1" transfer case drop yields. The current setup is to minimize vibrations, tide me over for the winter until I can afford an SYE and do it all right.
Vibrations are minimal, just wondering about what options are out there.

Thanks again all.

97CountryXJ said:

Thanks Madden, I think that is the solution I am looking for. It seems that the RE center pins will not be long (deep) enough to clear the shims and rest into the round hole in the spring perch. With that length, springs, shims installed, everything should stay secure.

I have taken into consideration the angle that the driveshaft is at.
That is why I asked the origional question about what degree of drop the 1" transfer case drop yields. The current setup is to minimize vibrations, tide me over for the winter until I can afford an SYE and do it all right.
Vibrations are minimal, just wondering about what options are out there.

Thanks again all.

Click to expand...

I was wondering if you ever found a solution? I know everyone seems to mention putting the fat end of the wedge towards the back which would nose the front of the pinion upwards. Well mine, like yours needs the front of the pinion to go DOWN 2* in order for it to be the same angle as my transfer case. This goes against everything I've read on here.

viperbluelx said:

I was wondering if you ever found a solution? I know everyone seems to mention putting the fat end of the wedge towards the back which would nose the front of the pinion upwards. Well mine, like yours needs the front of the pinion to go DOWN 2* in order for it to be the same angle as my transfer case. This goes against everything I've read on here.

Click to expand...

That can happen if you have a big shackle or something. As far as the center pin bolt, I usually make my own because they are a pain to find. I just go to the store and get a grade 8 fully threaded bolt and double nut it. Grind it round and then it sticks out far enough to use with shims.

if you are using your stock rear D/S and didnt install a T/C drop, then you may very weel need to shim pinion down to get the right angles. if you added a T/C drop with a stock driveshaft you need to set the pinion 1-2 degrees below that of the T/C. this article is a great guide to use. look at pictures to the right. makes it clear, as to what you should be shooting for.Jeepwire.Com Presents: Setting Your Pinion Angle

builder said:

if you are using your stock rear D/S and didnt install a T/C drop, then you may very weel need to shim pinion down to get the right angles. if you added a T/C drop with a stock driveshaft you need to set the pinion 1-2 degrees below that of the T/C. this article is a great guide to use. look at pictures to the right. makes it clear, as to what you should be shooting for.Jeepwire.Com Presents: Setting Your Pinion Angle

Click to expand...

With my TC drop my pinion is actually pointed 2-3* higher than the T/C. I think I need to point the pinion down 3* to get it close. Seems like that would put the driveshaft at some bad angles though.

My D-shaft angle went from 10* to 3* when i installed my 1" drop on my '89.

-PJ-

Which would be fine, but the TC drop is also cause bad angles on the front driveshaft due to my 01 having the low pinion dana.