Terrible vibration after auto trans repair!

[thammel]

Hi,

2002 XLS 4 door. The AT totally died 2 weeks ago and I took it to a shop for a rebuilt trans. They put it in and I had a terrible vibration above about 40-45 mph. It was also dropping out of drive while at a stop light. Took it back to shop and they said they fixed it but it still has this terrible vibration. Obviously, it's going back to the shop. Ideas about possible cause? Does the prop shaft need to be removed to pull the AT? If so, could putting it back wrong (i.e., not as it was originally) cause bad vibration?

Side note -after first repair, I jacked up the rear and looked underneath and saw really crappy workmanship; 1) 1 of the 4 bolts was missing at the rear prop shaft to differential flange and 2) 1 of the 2 bolts at the rear AT mount was not installed all the way. I was livid and the car went back to them the next day.

Any comments are appreciated!
Tom

 

[jakedrew]

U joints messed up on the drive shaft?


good luck

 

[sethmorgan]

The procedure calls for marking the relative positions of the drive shaft with its bolted on counterparts since the driveshaft is balanced after installation on the vehicle. Sound like it wasn't installed the same way.

 

[swetrid]

Check the orientation first but Ford also has a tsb for a certified driveshaft for noise and vibration.

 

[imp]

... Does the prop shaft need to be removed to pull the AT? Of course! If so, could putting it back wrong (i.e., not as it was originally) cause bad vibration? Of course!

Side note -after first repair, I jacked up the rear and looked underneath and saw really crappy workmanship; 1) 1 of the 4 bolts was missing at the rear prop shaft to differential flange and 2) 1 of the 2 bolts at the rear AT mount was not installed all the way. I was livid and the car went back to them the next day.
Any comments are appreciated! Those bolts are pretty heavy. Missing one will introduce plenty of vibration, driveshafts turn pretty fast. Did the vibration change any after the missing bolt was replaced? If no, the shaft was not put back in it's original orientation, as mentioned by another gentleman.
Tom

 

[thammel]

Thanks for the replies. You all verified what I believed to be necessary - marking the prop shaft/diff flange before removing. I'll be nagging the idiot shop tomorrow. Just makes me wonder - also they supposedly gave it a test drive. I just shake my head in frustration.

Thanks,
Tom

 

[imp]

Tom, FYI regarding driveshaft balance: Ford Shop Manuals recomment use of a worm-gear hose clamp, tightened onto the driveshaft, after checking for run-out, the hunky part of the clamp with the screw being located opposite the "high-side" of the runout. I figger that hunk of imbalance weighs just about as much as one of them there funky U-Joint flange bolts.......

Believe it or not! imp

 

[thammel]

Well, the problem was diagnosed and repaired as simply being loose prop shaft bolts. I hate it when I have someone else work on one of my cars!!!! Thanks for all your help and comments!

Tom