Transmission oil color?

[jim1941]

I have two 1976 AMC cars and discovered today that one of them has brown trans oil when I did some draining while changing the neutral safety switch. The other exact same car has the standard red color.  Book says use Dexron oil, but the new quart I purchased is red.  Is color important?  Thanks, Jim

[JACK M]

The brown oil probably used to be red.

Do they smell the same?

[Bloo]

If I found brown oil in that car, I would drain the entire thing, torque converter too, change the filter, clean the sediment out of the pan, and adjust the bands to the spec in the shop manual.

 

You'll probably need crowfoot wrenches and at least one small torque wrench. Don't work with the pan off in a dusty environment, and be extremely clean in your reassembly. Don't wipe stuff off with rags if it is going inside an automatic transmission. Wash any parts with solvent or brake Kleen, blow dry, and assemble. In 1976, all types of automatic transmission fluid had been red for longer than anyone could remember. Use fluid that is backward compatible to either Dexron II, DexronIII/Mercon or Chrysler ATF+3. Not every type of Dexron fluid is fully backward compatible today.

 

Brown means burned. The transmission has been badly overheated. Adjust the bands. Also be sure to adjust the throttle and kickdown linkage as shown in the manual as it does more than just kickdown on the Chrysler transmissions AMC was using in the mid 70s. If it is misadjusted it will cause the transmission to overheat and possibly destroy itself. The transmission might be shot, but I would give it every chance to be OK. Adjust the bands. Did I mention adjusting the bands?

 

Best of luck with it.

 

[avgwarhawk]

The transmission fluid was probably red and now brown after many miles.  Drain, install a new filter and gasket. Refill with fresh. Drive. 

 

[jim1941]

Thanks for the information and guidance.  Glad I asked!!  Car has been running fine for over a year of nice weather usage, but I won't wait on this.  Jim

[Larry Schramm]

Depending on the color of the transmission fluid after the fluid change, you might need to change the fluid twice to get it back to the correct red color without changing the transmission. 

 

Remember, oil is cheap compared to a new transmission.   

 

Historically transmission fluid is about 80-85% base oil and the rest are additives like detergents, anti rust inhibitors, anti foaming additives, and other items to keep all of the valves working free.  Just IMO.

Edited February 17, 2022 by Larry Schramm (see edit history)