It feels the same no matter what. It's the entire jeep. It's a pulsing vibration until 35-40ish then a really hard vibration that shakes EVERYTHING then a pulsing vibration after that.

 

It's in the steering wheel, the floor, everything. I have no clue.

 

When you ride with JUST a rear shaft, is the same kind of vibes or does it change. And does the steering shimmy or just vibrate. Trying to rule out bad u joints that just may be a bad coincidence. Hoping its not the TC. Also check TC fluid make sure there's still some

 

Jeep driveshaft number 52853500 is 32" long compressed. It was in the 01-02 WJs with 4.7 that had u-joint at the front output (some were CV, some were u-joint), and was used in all of the 02-04 WJs with 4.7 and the NP242-HD

Do you have the part number for the driveshaft that you used? I will add it to my database

 

I can get the part number after school, maybe earlier if I can find the thread I found it on.

 

Same exact vibration. It vibrates no shimmy. We filled the transfer case when we installed the sye and it never leaked (I've checked it like 10 times since) so I'd assume I still have fluid...

 

There's a chance you'd have to re open the TC. Make sure there's no play in the main shaft. That's the only thing I can thing of. Unless its motor/tranny mount related. You can check those first. No shimmy in the steering wheel rules out steering related for the most part, not 100%, but should be enough

 

This. You just eliminated driveshafts and angles. Check your crossmember mount for the tranny. Make sure that's mounted correctly and tight. Motor mounts would be more of a clunking, but still worth a check. Otherwise, it's time to take out that TC and rebuild it again.

 

I don't know if it would make a difference but I took out my transfer case drop when I put the sye in. There wasn't any play when we put the shaft in, and if I grab the yoke I can't move it laterally at all.

 

The transmission mount should be fine. I never touched it. Everything I've done is tight. What do you mean by rebuild the transfer case? More than uninstalling and reinstalling an sye?

 

Check your motor mount. Put her in drive, keep foot tight on the brake with the e brake on and rev engine high and see if the engine twists. Remember, this can all be coincidence that it happened at the same time. Maybe mounts went bad went you had the TC drop in. Want you to check the easy, free to check things first. Also make sure all TC bolts are.tight at the mating surface of granny. To be honest, you already ruled out most of the things I've personally encountered so now I'm just flinging ideas for ya now

 

I didn't take the transfer case out to install the sye so the tranny should be tight. I'll check the Motor mounts today, honestly they're probably bad.

 

Just redoing the SYE. Did you completely remove your TC when you put in the SYE? I'm so lost as to what it could be because everything is leading to the TC, atleast from what you've been describing in your posts. If you removed the TC, is it splined to the tranny properly? Like the guy said before me, all the bolts tight? How about your VSS? Is that too tight? Too loose? Are the vacuum lines hooked up? You need to backtrack EVERYTHING you and your buddy did. Something went wrong somewhere to cause this issue.

*edit* disregard the taking out part. I was typing this when you posted and didn't see you say you kept it in.

 

If the mounts were at lets say 65% before the TC drop. Then the drop made them worse because the strain and then you took the TC drop out and put the engine at right mount again. Maybe wallowed them out

 

VSS? Vacuum lines are good.