Howdy,

Replaced all 3 U-joints in hopes of eliminating that annoying whine from the driveline. The center U-joint was really rusted in one of the bearing cups and the "clunk" has been eliminated.

However - I now have driveline vibration from about 2000 - 2500RPM. Everything was indexed properly before removing the driveshaft and I indexed the configuration between both parts of the driveshaft before replacing each U-Joint.

The new u-joints have grease fittings and the old ones did not. Could this be the cause of the vibration? Maybe the weight of the grease fittings is enough to throw the driveshaft out of balance?? Do I have a shop re-balance the driveshaft?? Or, the other option is to buy new u-joints without grease fittings and do it all over again, which thrills me to no end.

Any assistance is much appreciated....

Stormie - '88 240DL (475,000 miles) + '89 765T (253,000 miles)

U-joints normally don't whine. The center bearing or a wheel bearing are
probably the source of the noise. Or maybe the diff is low on oil.
--
George Downs Bartlesville, Heart of the USA!

I replaced my old ujoints with grease-zerk-equipped joints and it had no effect on balance or vibration. As others have mentioned, check the tailshaft for play. The center support bearing should be replaced for sure. You can soak down the center bearing with some type of spray lube and then quickly go for a drive, if the whine is gone you have found the problem. There is fluid in the rear diff.. right??

matt


--
'82 240 - 178k & '93 945 - 147k

U-joints don't whine. Who told you that? As mentioned, the steady bearing will whine terribly, so did you check it while the shafts were out? You may also have a bad pinion bearing, or a bad axle bearing, or a bad overdrive unit, or a bad auto trans. They will whine for sure.

Did you replace the center support rubber donut and bearing? Are the arrows on the driveshafts lined up?