Well. Where to start.
Just put a new old tranny (from idi I used to own) in and it ended up having a pretty bad 4th gear syncro. Wasn't nearly as bad when I had it in the idi but it's pretty rough now and it didn't get more than 100 miles put on it after I owned before.
Clutch has been adjusted and definitely easier to push now and is much smoother from 1-3 gears.
On the driveline issue:
One issue I thought I could resolve is a vibration I am getting right at 55mph.
First thing I did was put in new ujoints cause it feels like it's coming from drive shaft. new ujoints didn't fix it.
Now with the tranny swap, I'm still getting a roar from underneath truck that has been there all along. It's not coming from floorboard, pedals, or steering wheel until I push clutch in at speed and then I feel it in the clutch pedal. It's almost like a shutter. Can feel it in the shifter **** too.
My thought is to clock the drive shaft 180 degrees and see if it improves. That doesn't cost me but a little time.
I checked the shaft in transfer case and I didn't feel much up and down play in the shaft when I resealed the rear housing and replaced rear seal which was leaking.
I'm concerned that it might be transfer case or rear end. What could I do to rule those two things out? Or does anyone have any suggestions on things to check out? Very frustrating. Good thing is, I have an extra tranny that I can go thru/rebuild over time if needed but I'll be posting a bunch more question if I get into that can of worms...Any help is much appreciated! was hoping a tranny swap would solve a lot of problems but I am at a loss...

 

When you were in the rear end, did you look at the gears? You could have a bad bearing in the pinion, causing a vibration and made the seal leak. Your gears are gonna wear out fast if they haven't already IF that is the case.

 

Thanks fordman. i did discover one more thing today.
Been having a touchy brake pedal. Noticed that the vibration gets horrendous when i push clutch in going around 40+ and brake heavily, the whole truck bounces. Doesnt do it as bad when I brake heavily in gear! Started thinking warped rotors but I got the blue ox up to speed and mashed ebrake to see if it would happen then too but wasnt nearly as bad on vibe. Probably bc its a slower process with e brake vs mashing brake pedal. Jacked up the truck afterwards and just spun wheels by hand and notice a good bit of drag for about half a turn then it feels like it lets go. Gonna be pulling rear wheels soon to inspect.

 

One thing you can do to rule out the rear driveshaft, but be careful...

Pull the rear DS, lock the TCase in 4-HI and engage the front hubs. Take the truck out and see how the vibration is in that case. Just be careful putting all the torque through the front end. Dont mash the throttle and do be ready for front outboard UJ vibration when cornering. It'll handle way different too.

When you changed the UJs in the rear DS did you change all three or just the 2 on the ends? My truck developed a vibration which came in at 55 MPH also. Figuring it was a UJ, I felt each one when I got to work that day. Only the center UJ was warm. Changing it alone solved the issue.
Rory

 

good idea. I'll have to try that. I only have two UJ's one at the rear end and other end near the TCase. I have a feeling it might be brakes but at least that would rule out drive shaft. I should have thought about trying that before! I'll be careful with it for sure.
thanks!