Question About Tranny Flushes

[1990lumina]

With all this talk about transmissions slipping and such, why is it not recommended to have a transmission flushed? Doesn't the flush take all the old fluid away with it, whereas just dropping the pana nd changing the fluid only gets some of the old shit out.

It was also said transmissions should not be flushed when they are old and have a lot of miles on them..what is the reasoning behind this? To me you'd want to be doing more preventative maintainace on a higher mileage tranny.

 

My other question is what if the car has had regular tranny flushes every year? Is it still bad to do them to a higher mileage tranny??

 

Thanks!

 

- Jeff L.

[TGPilot]

I don't think I have ever heard anyone reputable say it is bad to flush a tranny at any age. Getting out the old burnt and oxidized fluid has done wonders on a few cars in my past. Just doing the filter and pan fluid only does about 1/4th to 1/3th of the capacity so not much help cleaning things out... 8)

[GnatGoSplat]

I believe the reasoning is that a tranny that has never been serviced will be very worn, and the gritty stuff in the old fluid is why it still works at all. Flush it with new fluid, and the worn bands and clutches will start slipping and fail.

 

Anyway, I think flushing a tranny in decent condition is okay.

A tranny that dies after flushing didn't have long left anyway.

[HokemBokem]

I believe the reasoning is that a tranny that has never been serviced will be very worn, and the gritty stuff in the old fluid is why it still works at all. Flush it with new fluid, and the worn bands and clutches will start slipping and fail.

 

Anyway, I think flushing a tranny in decent condition is okay.

A tranny that dies after flushing didn't have long left anyway.

 

Yea I heard the same thing. One of my friends flushed the tranny is an old shity Mazda and not even a month later he was out of a car

 

Im kinda scared to flush mine so I think im just going to do a fluid filter change on it soon.

[cutlass1991]

I dropped the pan on my 4t60 with 60,000 on it. I let it drain and changed the filter, gasket, and when all was done, it took about 4-5 quarts of new fluid. Did I waste my time by not doing a flush? was doing this stuff beneficial at all?

[GnatGoSplat]

Drain and refill is just fine. Fluid that is 60% new and 40% old is still better than fluid that is 100% old.

 

Just as long as you can keep the fluid predominantly red, you'll be okay.

Red fluid turning brown should be changed.

Brown fluid = cooked fluid, and that's bad. Change it ASAP.

Black fluid = it's too late, don't bother changing it, it will blow up.

[patgizz]

i've had plenty of reputable trans shops tell me if someone left it go 100k without changing, don't bother cause you'll wash all the crap stuck to the clutches off and make it slip. my 93 was like that, my mom let it go to 150k without changing before i got it, i flushed it and it slipped badly for another 25,000 miles.

[maybe2fast]

the flush machine we have at work is really cool it splices into the trans line and as the old fluid comes in new fluid is put back. not allowing any settling of grit or anything. just my 0.02

[TGPilot]

Drain and refill is just fine. Fluid that is 60% new and 40% old is still better than fluid that is 100% old.

 

Just as long as you can keep the fluid predominantly red, you'll be okay.

Red fluid turning brown should be changed.

Brown fluid = cooked fluid, and that's bad. Change it ASAP.

Black fluid = it's too late, don't bother changing it, it will blow up.

 

Sorry but I make assumptions sometimes that things are common sense. That is very true that any maintenance other than a full rebuild with very dark or black fluid will cause critical failure. 8)

[THe_DeTAiL3R]

I dunno, on my 88 GP when I droppped the pan the fluid was black like coffee. I never had a problem with it through like 50,000km that I had it.

[buckethead]

I think people just say that because the majority of people never change their fluid untill there's an actual problem with their tranny. I know both my parents have never done a tranny flush on either of their cars at regular intervals, they just waited untill they "had" to do a flush. So by the time they take it to the shop to have the fluid changed, it's already too late for their transmission. The flush doesn't do anything to fix it so it just dies. Therefore people are associating flushes with failed trannies. Just my hypothesis.

 

I think the main thing is to change the fluid before there's any actual physical damage to the parts inside the tranny. If it's just burnt fluid with no worn down parts, go ahead and change it.

[Canada]

This is my take on the subject:

 

Tranny flushes ARE just fine on a tranny in good condition.

 

BUT.

 

If you have a shop do this, make SURE they do not use any additives. Most of the places around here use flush machines sold by Wynns and THEY want you to also use their flush and shudderguard additives.

 

Do NOT.

 

GM specifically states in a TSB (and I gather Chrysler does too) that you should NOT use any additives when flushing a trans. Apparently the flushes (with additives) tear up the clutches in higher mileage trannies, and/or scour seals enough to cause them to leak and thus slip....bam, dead tranny

 

NOT a good state of affairs.

 

 

 

On the other side of the coin you have a traditional pan drop. Nothing is wrong with this, but as mentioned, it only gets 40-60% of the fluid.

 

 

 

*I* do the following (going off of advice from one of my ASEP instructors):

 

Drop the pan.

 

Replace filter.

 

Cut open old filter (very easy to do....use a vice and a screwdriver and you can be into it in <2 minutes) and inspect for clutch material and excessive metal. I also look at the bottom of the pan and look for the same stuff. Clean off the magnet too.

 

Then........*IF* everything checks out (and the trans was reasonably healthy to begin with), I proceed to button the bottom end back up, and top off the tranny. At this point I pop off the return line from the tranny and pump out the old fluid (adding as I go) until I get nice new, red ATF. You could also hook up a flush machine at this point, but again...DO NOT USE THE ADDITIVE CRAP.

 

This gets a FULL fliud swap, with NO additives involved AND a nice new filter (and allows me to check for problems). It also gives you the option to STOP after the pan drop if you DO find anything wrong..........

[pwmin]

its not good. dont do it. just change your fluid and filter regularly and maybe put in some BG trans plus. flushing does ruin bands by taking the coating off.

[Canada]

its not good. dont do it. just change your fluid and filter regularly and maybe put in some BG trans plus. flushing does ruin bands by taking the coating off.

 

Read my post above and see why you are both right and wrong.

 

 

Flushes can be completely ok..........you just have to be careful and NOT use additives (this means no "trans plus" either).

[Vampyre73]

Has anyone ever used Lucas Oil's Transmission Fix? I was thinking about using it as a preventative maintenance type additive to the existing old fluid. Personally, I'm of the fluid/filter change variety - I've had transmissions develop sudden problems after full flushes before.

[THe_DeTAiL3R]

I used Lucas before in my 88 GP. I actually used it as a temp fix for leaky trans pan gasket! :shock:

 

Anyhow my tranny was fine to begin with, so I didn't notice anything... I later dropped the pan and put on a proper gasket.

[HokemBokem]

I used Lucas before in my 88 GP. I actually used it as a temp fix for leaky trans pan gasket! :shock:

 

Anyhow my tranny was fine to begin with, so I didn't notice anything... I later dropped the pan and put on a proper gasket.

 

I heard that Lucas fucks your shit up! All soapy and shit.

[THe_DeTAiL3R]

I used Lucas before in my 88 GP. I actually used it as a temp fix for leaky trans pan gasket! :shock:

 

Anyhow my tranny was fine to begin with, so I didn't notice anything... I later dropped the pan and put on a proper gasket.

 

I heard that Lucas fucks your shit up! All soapy and shit.

 

Yeah that was my old car, which went to the junkyard with a good engine/trans. The rest of the car was an ugly rustbucket. I haven't used Lucas in my 95 GP.

[HokemBokem]

I used Lucas before in my 88 GP. I actually used it as a temp fix for leaky trans pan gasket! :shock:

 

Anyhow my tranny was fine to begin with, so I didn't notice anything... I later dropped the pan and put on a proper gasket.

 

I heard that Lucas fucks your shit up! All soapy and shit.

 

Yeah that was my old car, which went to the junkyard with a good engine/trans. The rest of the car was an ugly rustbucket. I haven't used Lucas in my 95 GP.

 

Or maybe im wrong and its just the oil additive shit. I remember a long fuckin time ago I posted some oil additive stuff I got, and someone posted a link where this guy tested it out with gears and shit. Basically showed the Lucas sucked dick and got all soapy and fucked shit up.

[TGPilot]

I have told this story once before on here when there was a slipping tranny issue.

 

I had bought a 1992 SSEi at auction. Found out the tranny was slipping like crazy in 2nd to 3rd and would hardly pull in third.

 

I tried Lucas...no difference.

Dropped the pan and filter change...no difference.

Took it to a tranny shop for a "proper flush and filter change"(Not a quicky shop)...no difference.

Buddy of mine told me to put a pint of brake fluid in the tranny...FIXED!

 

I sold the car to a guy telling him about the tranny and he got a bargain out of me. Funny part was he drove it all the way from Colorado Springs to Illinois...then from Illinois to Daytona Bike Week in Florida...then back to Illinois with a side trip to Maryland on the way back. THE GUY SAID HE NEVER FELT EVEN A HINT OF SLIPPAGE!! :shock:

 

Apparently the brake fluid goes in and soaks/swells the seals and gets rid of slippage from time to time. Not a fix all cure all for all issues...but worked like a charm on that 4T60-E... 8)

[z34_nut]

when i was having tranny issues way back in the day, i never once flushed it, fien grime and old clutch meterial accually assits the clutches and bands..

 

i simply changed the fluid (it was black at the time and would shift into nuetral at will) and the car ran for another 5k miles..

 

then the tranny blew, but hey, it has 233xxx miles on it...

 

either way, i was able to make it last 5k more..

 

now i got a new tranny with about 3k miles on it, all beefed up, so lets hope that this isn't an issue.

[Stealth]

I tried using lucas, because I didnt have money and I didnt want to change the fluid incase it blew the trans it had like 230kms on it and the fludi was prety dark brown th elucas make the shifts a bit better, then abotu 1-2 months later I changed the fluid and it runs great now

[ron350]

This debate will go on forever because there are so many different flush machines out there.

 

I do know you can’t hurt a healthy transmission by changing the fluid and filter, early and often.

[95 3-4]

Best thing to do is put in a drain plug and drain it every 3rd or 4th oil change

 

I know the Torq-Shift behind the diesel in ford trucks has a factory drain plug w/ spin on filter on the side The Allison in the Gm trucks may also have the same set up

[Canada]

The Allison does.

 

I say the best thing is to completely change the fluid and filter in the transmission when it needs to be replaced.