2001 XC70 Clunking noise in rear axle

[peterhowell]

225,000 km Vehicle has been maintained regularly.

When travelling up an incline at low RPM such as in a town/city. There is often a severe clunking noise when the transmission engages a lower gear. This noise appears to come from the rear drive shaft/universal joint area.
Another possible related problem is when the transmission is hot after an hour or more use, there is a small delay (2/3 seconds) when moving from 'Park into Drive' for the gear to engage the rear wheels.

Could you please advise me of the problem and a possible solution. I have already had the transmission serviced and reset but this did not cure the above problem.

Thank you

[precopster]

It's more than likely the constant velocity joints in the rear driveshaft are in need of rebuild. Colorado driveshafts can supply the parts to rebuild the driveshaft. The Bevel gear (AWD differential behind the engine) may also be at fault. Has the bevel gear's fluid ever been replaced? They can be sucked out and have new 75W-90 hypoid gear oil placed in them.

The transmission has sticking solenoids caused by poor quality bushings used in the SLS, SLU & SLT solenoids in the 2001 and 2002 model years. The bushings collect metallic particles causing them to stick. First thing to try is a succession of drain and fills via the 23mm drain bolt underneath and dipstick hole for refilling. Three drain and fills with JWS-3309 rated fluid may help.

A valve body rebuild may save your transmission. If transmission fluid doesn't have a history of regular replacement you may be wasting your money.