Transmission Flush

[thebird00]

Thinking about changing the fluid in mine cause I need a new pan gasket anyway.

But, has anybody ever heard about transmission flushes, from a service station, making transmissions go out?

Mark

 

[greyhoundjc]

I've heard that it's a bad idea to change the fluid in a trans that is on its last leg, but never anything bad about having one flushed.

In fact, AFIK flushing is the ideal way to do it since draining just the pan still leaves around 4 qts in the torque converter and lines.

 

[4xcrazy]

you are going to get mixed responses about this, i personally feel that if you do it to a trans with 150k miles and up, *MAYBE* you are one of the unfortunate ones that it kills,,,i dunno, alot of people seem to think that the dirt is holding things together *cough-Pauly-cough* others say if pushed contaminates aroungd to a point that will damage other parts when youget everything back together.

I would say it could be the best thing for a transmission if it is done since new/rebuilt at every 60k or so, depending on driving conditions as well,,,

If you are already having problems with the transmission, with shifting or whatnot, i *might* be hesitant to do it. Change out the fluid alittle more frequently for the next few months with just pulling the pan and filter replacement and see if the fluid starts to clear up some,,,

This "trans flushing" is a weird topic around here

 

[Blue85]

If you are going to flush, you can do it yourself and save some bucks. Search here for more info.

 

[longbedder]

Power flushing is not terrible, but less than ideal in my opinion. It dislodges crud and forces fluid around in abnormal ways. Like 4xcrazy said, it can probably be alright if done regularly to an already-fairly-clean tranny.

What I prefer is to drop and clean the pan, change the filter, reinstall the pan, and then disconnect the cooler sending line. Using a piece of tube, route the fluid from the cooler line into a waste oil bin. Run the engine (replacing the fluid via the dipstick tube as it gets pushed out) until the fluid dumping out runs clean, then reattach the cooler line. That way you have almost all fresh clean fluid throughout, and none of the potential downsides of power flushing.

 

[Leper]

Power flushing is not terrible, but less than ideal in my opinion. It dislodges crud and forces fluid around in abnormal ways. Like 4xcrazy said, it can probably be alright if done regularly to an already-fairly-clean tranny.

What I prefer is to drop and clean the pan, change the filter, reinstall the pan, and then disconnect the cooler sending line. Using a piece of tube, route the fluid from the cooler line into a waste oil bin. Run the engine (replacing the fluid via the dipstick tube as it gets pushed out) until the fluid dumping out runs clean, then reattach the cooler line. That way you have almost all fresh clean fluid throughout, and none of the potential downsides of power flushing.

I agree with this method.

Also, if you are power flushing a tranny with 100K on the FLUID it may not make it out of the shop.

 

[thebird00]

Thank you all. This is some good info.

The main reason I asked is because a friend of mine had his 93 dodge trans power flushed and 200 miles later it goes out on him. I would think some of the service centers would advise against power flushing a high milage trans, but I guess for some its just extra money if they bring it back to replace the trans altogether.

I might try what longbedder suggested. Just hate to replace a trans because you think you are doing the right thing and getting fresh fluid in it.

Guess I could just let it keep leaking and just add new fluid til its all fresh.

Mark

 

[johnnychimpo]

I had a Nova in high school w TH350 in it. I changed the filter & fluid got in it & it wouldn't move. The rebuilder told me that the clutch & band particles in the fluid were the only thing making it move prior to the fluid change.

 

[80' 427]

I have done lots of high mile trannys with out a problem but if it is getting weak or has a problem now it will not fix it. Think of it as changing oil to fix a rod knock.

 

[fried_guy]

My friend just changed the fluid in his tranny after 200K and it died on him 2 days later.

Also, before I knew my girlfriend, she thought that changing the engine oil was the same as adding more when it's low. When I found out about this I immediately changed her oil and filter. The stuff was like goo... sludge city. Anyway, the next day her car died on the freeway.

Granted, I'm not a professional mechanic, but I've changed oil enough to know how to do it blindfolded.

My theory is that changing oils on something that is really caked with goo will only move the junk around to another spot which may or maynot block the flow of the oil and cause failure. Just a theory!

I think that flushing the system thoroughly wouldn't have that problem.

 

[Kp]

I took my Jeep GC with 100K on it to a tranny shop and asked him to perform a flush, and he recommended against it, for exactly the reasons i am hearing here.
he told me he'd love to charge me the 79.99 for the complete flush and fill, but he would prefer to just drop the pan, clean the filter and charge me 29.99.
He said that the flush can cause particles to break free, and he's seen trannys that were functioning fine, die soon after the flush.
I took his word for it.

 

[dick_landy]

i had an 30 year old wagon, pulled the oil burning engine, dropped in a big block with over 450hp, dumped the tranny fluid and put a shift kit in it, bagged the piss out of it, and nothing ever went wrong. even the u joints were still good! maybe im lucky.