How to re-shim driveshaft correctly?

[Xenocide]

I just swapped an engine, transmission, transfer case, driveshaft, rear end (4 bolt) and axle cups from a 92 into a 90. I installed a new clutch and lightened-flywheel at the same time. Neither car had vibration issues before the swap, but now I get bad vibration with the clutch out all speeds. Pushing the clutch in seems to smooth things up pretty significantly at any speed. The wheels should still be balanced fine and the carrier bearings and u-joints are pretty good; I'm thinking my vibration is from the driveshaft alignment based on research and the fact that playing with shims seems to have helped the issue somewhat.

Does anyone know a trick to aligning the driveshaft on these cars or am I best to take it to a transmission shop or does this issue sound like something other than the driveshaft alignment? I unfortunately didn't keep track of where the shim washers were on the carrier bearing mounts on either driveshaft and am having the afore-mentioned vibration.

 

[92awddsm]

As for the carrier bearings, (from floorpan to retaining nut) there should be a metal washer/sleeve, rubber bushing, carrier bearing, rubber bushing, metal washer/sleeve, flat washer, and then the nut.

If the vibration goes away when you disengage the clutch, it has nothing to do with the driveshaft. It sounds more like it is a clutch disk problem actually. Just think, when you hit the clutch, the only thing that stops spinning is the disk. The driveshaft, axles, pressure plate, flywheel, and wheels are still rotating, but the clutch disk is the only thing that has stopped spinning. With this being the only variable, what makes you think it is a driveshaft problem?

About the only time the driveshaft does anything stupid is on hard launches. During this period, you might hear a thumping on the floorpan but it usually isnt accompanied by any vibration. The cause of this is from worn rubber bushings inside of the carrier bearings. Look up www.vfaq.com under drivetrain and you will see what I am talking about.

 

[DSM90AWD]

^^^^ What he said, D/S is most likely not your problem.

In my experience, when I did the Carrier Bearing "silicone mod" all dampening normally provided by the Carrier Bearing assembly was gone and could feel severe driveshaft due to a bad rear u-joint. The vibration was there before, just that the CBs were absorbing it at the expense of premature wear. With the CB pumped full of silicone, it was in effect a solid unit now and it's ability to dampening was near nil.