Transmission maintenance
 

I have a loaded 2004 GTS with the 3400/4t45. I'm at 160,000+ and the transmission fluid was never changed. I know... I tried at about 140K, but the dealer mechanic recommended just leaving it because it was possible that I would start having trouble once fresh detergent fluid started loosening up all the gunk.

Well, a few thousand miles ago it started shuddering if I pull out at hard throttle. Also, it shifts 1-2 a little late at hard throttle. Otherwise, it's OK: 2-3-4 are OK, and reverse is OK. So I don't know if I should do anything. The shuddering, which is my greatest concern, could be the torque converter.

The car is otherwise in excellent running condition, with only minor cosmetic issues, and I'm not ready to junk it.

I would just run it as is. Long as possible. I recently bought a car with 154k on it. (3.4 alero) and the previous owner never flushed trans, im at 173k miles now and i wont touch it. Hoping it lasts for a good while.


But the dealer is right. If it wasnt done at 100k I personally wouldnt touch it. But up to you.

I agree with sleepy. If it's never been done, don't touch it. The clean fluid will clean off all the clutch material that's floating around and it won't shift at all due to there not being enough clutch material to take up the gap between the clutches and the steel discs. The shuddering is probably the torque converter clutch. So just run it as is and wait for the time when you have to put a new transmission in.

what about a transmission with 105k miles? I've been debating doing it myself...

Do it now or never

It's always OK to drop the pan, drain what you can, replace the filter, and refill. I did this on my Escort at around 165K miles, and I now have 236K miles on that transmission.

Actually I siphoned out what I could and refilled 3X around 1-2 weeks apart before dropping the pan and replacing the filter, but you get the idea. A flush might be bad, but a gradual change or drain and fill is actually good for the transmission.

I wouldn't touch it.

Should of started a poll... I'd leave it

This is how I feel about the subject:

Transmission Flush Myths

At the very least, drop your pain, change the filter and replace the drained fluid. It's not going to lose that much fluid with all the clutch pack material floating around in it, if that's what you think is keeping the things still shifting in your minds. So what is the big problem, the myth started with fluid flushes, not general maintenance.

I don't see why on earth you wouldn't want to change your transmission fluid. I can not speak for the alero, my 5sp being the one the only one I have serviced on an alero, with witch a fluid change did it good. On the intrigue however I did it a few months ago. Never done before, 180,XXX miles. It had long shifts on occasion, and hard shifts often, and overall lag. I dropped the pan and found a small metal shard, and the bottom of the pan to be coated with a thick layer metal shavings, it was a sludgy super metallic mess. I removed the filter then adjusted the front of the car level, then back up to drain all the fluid I could. While level I had a quart of regular Derxon III I poured through for a little flush. Reassembled with a fresh filter and clean pan, filled to factory spec, checked and topped off per instruction manual. Since the car has traveled 800+ miles to homecoming and a weekly trip of 180miles + everyday driving. Overall I plan to do it again in 50,000 miles, no long shifts, fewer hard shifts, quicker shifting in general, and confidently leaving and entering park. I expect it to last the rest of the life of the car.