rbc

2001 taco 4cyl auto with 89k miles.Runs great but tranny fluid slightly dark. I have owned truck since 75k miles and have not changed tranny fluid. I have heard some people say that you should not do tranny flush when you have about 100k because it may loosen up sludge and then cause problems.
What are your experiences or advise on a tranny flush?
thanks
rbc

Caffeine

drain the oilpan and fill it a couple of times first before flushing. It's a little easier than hammering the transmission with new ATF.

Team420

I would say flush it, and change screen, Now is the time, I believe regular svc intervals are 60k...it is bad to flush when you get in excess of 100k say like 140+...but i think you should be fine under 100k

Team420

hmmm...nice tip...never would have tried that

runner00

I have 116,xxx miles on mine, I was planning on doing the same (flushing the a/t fluid) when I install my trans cooler for towing. (Just draining the fluid though, no power flush)

I was just going to drain it, fill it and the continually change the fluid every other oil change to keep it fresh.

I understand that an old trans might be adapted to its dirty environment. But I figured that it was good preventative maintenance to flush the fluid and keep it fresh before it becomes too contaminated. ( my fluid is currently a light brown not dark)

This sort of concerns me, that swapping the fluid could cause room for concern.

Doen anyone have any further/deeper info on this?

nfrantz007

My tranny was not gearing down when it should when coming to a stop. With a 160k on the clock I was a little worried but did a BG transmission flush and it fixed the problem. Maybe I got lucky but it worked great for me with no issues 20,000 miles (and counting) after the flush.

I'll be adding a tranny cooler soon and plan on pulling the pan, switching to amsoil atf, and checking the filter... I'll try to keep everyone posted with what I find.

Man4God

As I understand it, the new fluid is not the problem with a tranny flush on a high mileage transmission that has never been flushed regularly. The problem is with the "high" pressure input of fresh fluid and extraction of the old fluid. The pressure can loose things that should just be left alone.

I am in the same boat. My transmission has been acting up a little lately and I KNOW it needs fresh fluid. So I am going to use the "gravity" method to do it when I have the time, money and weekend to get it done.

mt_goat

All the flush machines I've seen, just use the tranny ATF pump to do the flushing. Its not any more force than what the tranny does while you are driving it. I'd go ahead and flush it myself, but after taking the pan off and cleaning the magnets and changing the filter first. If the tranny is so far gone that flushing sends it over the edge then it probably wasn't going to go far anyway. Some of those places that do flushing will even give you a warranty against failure (not sure how long, maybe its 20 seconds or 20 feet which ever comes first)

84RNR

I have both of our daily drivers flushed every two years with BG equipment. Our 2003 Tahoe had 120K miles when we bought it from a family member who had never touched the trans fluid. I had it flushed and no problems and it's been almost two years and another flush is due around the end of summer. I have them do the brake system, power steering and cooling system done at the same time as the trans flush. No problems on any of them. 56k miles on Tacmoa (bought new) and 147k miles on 03 Tahoe and again no issues.

The only thing about draining and refilling the trans is that you never get all the old fluid out.

Maj

The reason some feel that flushing is a bad thing on a high mileage rig is that the new tranny fluid while have a detergent effect on any crud currently clinging to parts. The crud can dislodge and clog things up. So the dirtier your current fluid is the more likely you might have crud buildup.

Man4God

Ok, so one would think that if there is more crud built up, then it would make sense to do a flush, then 5K or so later, have it flushed again. No?

Maj

Well, you are assuming that the first flush does not dislodge debris that clogs and ruins your transmission. I am certainly not a tranny expert and there is even disagreement among those who are as to the likelyhood of a clog. Try calling several transmission shops in your town and see how many different answers that you get about flushing high-mileage vehicles.