Recently the transmission (AW70) in my 1991 740 NA wagon started slipping. I was only a mile from home and by the time I reached the driveway, the engine was revving but the car was hardly moving. As I came to a stop there was a whine from the transmission that I never heard before.

The car has 320K miles. ATF has been drained from pan or flushed about every 50K miles. Did some checking and the ATF level is normal but the fluid is brown. The radiator coolant in the coolant reservoir is at a normal level but the coolant is also brown - about the same color as the ATF.

Either the coolant has a lot of rust in it (last replaced 60K miles ago) or the oil cooler in the radiator is leaking ? If there was a leak, would the ATF and radiator coolant levels still be normal ?

I was planning to remove the transmission pan and check the filter, but now I am thinking that will be useless unless the radiator is first replaced. The radiator is a plastic Volvo unit that was installed about 120K miles ago.

Would appreciate any advice,

Thanks,

Mike