Driveshaft Runout / Balance Problems

[4Runner5]

Can anyone explain 20-25 thousandths of static runout that drops to 3-5 thousandths once spun up? Saw it on the dial gauge with my own eyes at both ends, middle was better. How can this be?

Guy at the driveline shop said "Never seen that before. Don't really have an explanation for it."

He was able to improve balance from '4 bars' to '2 bars' but it still shakes on the highway. The target is '1 bar'.

It's a 2002 Toyota 4x4 slip yoke rear driveshaft with CV at the transfer and u-joint at the differential, 140k miles. Never had any vibration issues until recently when a shop removed rear driveshaft to rebuild the rear diff and replace u-joint. Soon as I got on the highway moderately severe vibration/boom/rumble. That was on a Friday afternoon. Drove as slow as possible until the next Tuesday. Took it back and a day later their story was "U-joint was missing a c-clip", we put it back on." Better but still vibrates. These guys didn't matchmark flanges or shaft sections either. Got driveshaft balanced, better but still vibrates. Had u-joint first shop put in replaced with Toyota u-joint at different shop. Big improvement but still vibrates. Took to a different shop for a second balance (mentioned above), better again but still vibrates at highway speeds. Not sure what to do next, any advice appreciated.

 

[Nick1994]

You said you had the rear diff rebuilt as well. You might have had 2 problems, diff done wrong and the driveshaft out of balance.

 

[NYSteve]

Think Nick is right...if they messed up a simple u-joint, what are the chances they got the rear diff right?

I would thyself over to East Coast Gear Supply ASAP. They are the experts on Toyota drivetrains and will set you right. Google the forums for feedback on these guys...it's impressive!

http://eastcoastgearsupply.com/

 

[Trav]

Originally Posted By: 4Runner5
Can anyone explain 20-25 thousandths of static runout that drops to 3-5 thousandths once spun up? Saw it on the dial gauge with my own eyes at both ends, middle was better. How can this be?

Guy at the driveline shop said "Never seen that before. Don't really have an explanation for it."

He was able to improve balance from '4 bars' to '2 bars' but it still shakes on the highway. The target is '1 bar'.

It's a 2002 Toyota 4x4 slip yoke rear driveshaft with CV at the transfer and u-joint at the differential, 140k miles. Never had any vibration issues until recently when a shop removed rear driveshaft to rebuild the rear diff and replace u-joint. Soon as I got on the highway moderately severe vibration/boom/rumble. That was on a Friday afternoon. Drove as slow as possible until the next Tuesday. Took it back and a day later their story was "U-joint was missing a c-clip", we put it back on." Better but still vibrates. These guys didn't matchmark flanges or shaft sections either. Got driveshaft balanced, better but still vibrates. Had u-joint first shop put in replaced with Toyota u-joint at different shop. Big improvement but still vibrates. Took to a different shop for a second balance (mentioned above), better again but still vibrates at highway speeds. Not sure what to do next, any advice appreciated.




There is no explanation, the shaft tube itself cannot unbend bend itself period. It either wasn't mounted properly or the flanges are tight at the U-Joints and need spreading to loosen them, it has a damaged flange weld or cheap U-Joints. It either needs a proper repair, pressing it straight so it has less than .02 run (pref .01) out of round or otherwise repaired to bring it into spec.

You cannot balance a bend out and that's whats run out is, it can be the tube itself or the connecting pieces. Balancing can only compensate for a heavy side by adding weights to the light side, like a wheel balance.
Find another shop, these guys sound like the gang that cant shoot straight.

 

[02SE]

Originally Posted By: Trav
Originally Posted By: 4Runner5
Can anyone explain 20-25 thousandths of static runout that drops to 3-5 thousandths once spun up? Saw it on the dial gauge with my own eyes at both ends, middle was better. How can this be?

Guy at the driveline shop said "Never seen that before. Don't really have an explanation for it."

He was able to improve balance from '4 bars' to '2 bars' but it still shakes on the highway. The target is '1 bar'.

It's a 2002 Toyota 4x4 slip yoke rear driveshaft with CV at the transfer and u-joint at the differential, 140k miles. Never had any vibration issues until recently when a shop removed rear driveshaft to rebuild the rear diff and replace u-joint. Soon as I got on the highway moderately severe vibration/boom/rumble. That was on a Friday afternoon. Drove as slow as possible until the next Tuesday. Took it back and a day later their story was "U-joint was missing a c-clip", we put it back on." Better but still vibrates. These guys didn't matchmark flanges or shaft sections either. Got driveshaft balanced, better but still vibrates. Had u-joint first shop put in replaced with Toyota u-joint at different shop. Big improvement but still vibrates. Took to a different shop for a second balance (mentioned above), better again but still vibrates at highway speeds. Not sure what to do next, any advice appreciated.




There is no explanation, the shaft tube itself cannot unbend bend itself period. It either wasn't mounted properly or the flanges are tight at the U-Joints and need spreading to loosen them, it has a damaged flange weld or cheap U-Joints. It either needs a proper repair, pressing it straight so it has less than .02 run (pref .01) out of round or otherwise repaired to bring it into spec.

You cannot balance a bend out and that's whats run out is, it can be the tube itself or the connecting pieces. Balancing can only compensate for a heavy side by adding weights to the light side, like a wheel balance.
Find another shop, these guys sound like the gang that cant shoot straight.


As a (former) Master Tech, and 3rd gen 4Runner owner, what Trav said.

There are lots of parts changers out there, that have no clue how to diagnose and then truly fix a problem.