Transmission Experts Weigh In

[Scott ZHP]

Mine has 170k on it; I've changed the filter and fluid twice, once at about 95k and again at about 165k. Be 100% sure you remove the filter neck seal from the transmission. It sometimes stays behind when you pull the filter down.

I've been using Valvoline Maxlife multi-vehicle, with zero issues. Still shifts like the day I bought it (I bought it new in 01). First fluid change, I got about 4 quarts out. After a week or so, I drained that and refilled again. Same thing on the second change.

I also replaced the trans cooler/heat exchanger at 165k, along with the trans thermostat/expansion tank/radiator/cap.

[Overboost]

Originally Posted by Scott ZHP

Mine has 170k on it; I've changed the filter and fluid twice, once at about 95k and again at about 165k. Be 100% sure you remove the filter neck seal from the transmission. It sometimes stays behind when you pull the filter down.

I've been using Valvoline Maxlife multi-vehicle, with zero issues. Still shifts like the day I bought it (I bought it new in 01). First fluid change, I got about 4 quarts out. After a week or so, I drained that and refilled again. Same thing on the second change.

I also replaced the trans cooler/heat exchanger at 165k, along with the trans thermostat/expansion tank/radiator/cap.

Thanks Scott, great feedback. You are the 3rd member to mention using MaxLife with no issues so I am happy I made that choice. At $17.49/gallon it is a easy call to do multiple drains and fills. How did your fluid look at 165,000 after 70,000 miles from the original multiple drain and fill at 95,000 miles?

[Scott ZHP]

Originally Posted by Overboost

Thanks Scott, great feedback. You are the 3rd member to mention using MaxLife with no issues so I am happy I made that choice. At $17.49/gallon it is a easy call to do multiple drains and fills. How did your fluid look at 165,000 after 70,000 miles from the original multiple drain and fill at 95,000 miles?

Fluid at 2nd drain looked and smelled fine, and the pan magnets had less fine sludge around them. My shaft seal is leaking a bit, so I'll probably change again in the fall.

There's a guy named Richard Crich who owns a shop called Precision Transmission in Amarillo, TX. His videos of GM transmissions are worth watching, either FB or YouTube.

[Caryalon]

I own a transmission shop.I would be hesitant to change fluids at 180k miles of it hasn't been done before, but that's mostly because of i do it for a customer, I am on the hook.

I would drain the fluid / drop the pan and inspect before changing. If the fluid is clean and clear, but dark, change it. If the fluid is burnt, or thick, or you find metal in the pan, changing the fluid is not a good move.

By the way, Dexron is backwards compatible - so Dex VI covers Dex III. The Valvoline and Castrol multi ATF fluids are good choices.

[Overboost]

Originally Posted by Caryalon

I own a transmission shop.I would be hesitant to change fluids at 180k miles of it hasn't been done before, but that's mostly because of i do it for a customer, I am on the hook.

I would drain the fluid / drop the pan and inspect before changing. If the fluid is clean and clear, but dark, change it. If the fluid is burnt, or thick, or you find metal in the pan, changing the fluid is not a good move.

By the way, Dexron is backwards compatible - so Dex VI covers Dex III. The Valvoline and Castrol multi ATF fluids are good choices.

I am taking this advice on saving the original fluid in a new drain container just in case it is evident there is any issues of severe wear inside the transmission.

At this point, the transmission runs and shifts perfectly and is right at that point of no return on mileage for fluid change for sure but if I don't do it now, I will never know. There is not a lot of HP on the business end of the box and I never lean on it so I am assuming it will be fine.

[Overboost]

No shipment yesterday but it all showed up this morning. I pulled a little oil out from the fill plug to look at the condition of the fluid. Looks very clean with no hint of any metallic material. Even smells fine, no burnt smell. Time to pull the pan.

[Overboost]

Pan off. Amazing inside. There is some magnet cleanup but normal and doing its job. Really can't believe there is 180,000 miles on this transmission.

[Overboost]

And complete

Cleaned up the pan, put on the new filter and buttoned it all back up. Torque on the pan bolts at 10nM. It took exactly 1 gallon cold and then fired up INPA to watch the temperature. Started the engine, went through P-R-N-D and then sport mode 1-2-3 (4-5 not available with brake on) and then back to auto mode and through D-N-R-P and back through it again watching the temperature. Pumped in another 3 quarts running at 38C (100F) and it just started dribbling out.

Took it out for a couple of errands and actually feels better although it never shifted hard or gave me any issues but it definitely feels smoother.

Disregard the dirty claw marks from my oily hands on the exhaust pipes. Still a rookie.

[Scott ZHP]

Originally Posted by Overboost

Pan off. Amazing inside. There is some magnet cleanup but normal and doing its job. Really can't believe there is 180,000 miles on this transmission.

That's about what mine looked like at 95k:

[haigha]

Great write-up, OB

My fluid was clean too. I think my problem was the leak at the mechatronic sleeve which lead to low ATF.That was likely the cause of the harsh shifts in the lower gears, which have gone away since I did the MaxLife drain/fill three times. Shifts as good as new now.