tranny flush.. 3.4

[96tsport]

Haynes sez drop the pan & change the filter at ~30k. Put on ~45k in the last 2 years & dunno when it was done last, but the fluid looked pretty good..

Looked it up online & found a link that talked about the above method changing very little of the oil (mainly what's in the pan) & mostly old fluid gets recirculated.

Went to a lube joint to inquire about a flush & they want ~120 bucks (includes the filter). I asked "how's about if I do the filter (they just flush it)?" That was ~90 bucks. We discussed whether I should do the filter before or after & I think the young fella said I should do it before & then bring it in for a flush.

When I asked why that way, answer was ~ "gotta do it right or you can 'shock' the tranny".. not good apparently..

Thought that was ..abit funny but dude was serious..

What's the best way with a 3.4?

[Jrs3800]

If you have the miles on the trans I'd say forget the flush... Drop the pan, replace the filter... You will need about 6 quarts of Dex III compatible trans fluid for a 4T60-E.... This is at the least about half of whats in the trans...

A failure after a flush is sort of a myth... If it fails after a flush it was bound to fail on you in the first place..

Do I recommend a flush... No... I have never done this to any of my cars and have friends that have done the same.. Just fluid and filter changes... 172k on my 95 4T60-E and its still going... 140k on the just wrecked 91 Bonneville and that trans is still strong..

I'd say drop the pan, replace the filter and refill with new fluid... and do this once a year...

How many miles on the trans?

[wafrederick]

I also agree,do not flush and GM does not recomend doing this,says in the factory service manual.Do you want the dirt,metal shavings and clutch material in the valve body?If you say no,right answer.I know a transmission shop in my area that does lots of valve body cleanings and rebuilds due to a flush with the machine.I also replaced one transmission in one due to a flush that was done with the machine.Problem with the machine is that it pushes the dirt,metal shavings and clutch material into the valve body causing lots of shifting problems and that is not good doing damage to your transmission.

[96tsport]

Originally Posted by Jrs3800

How many miles on the trans?

Same as the engine, van shows ~ 245 thou kilometers. Bought it a few years ago at ~ 200k, unknown prior history.

I'll just drop the pan & do the filter. Real glad I asked about it, the lube joint (another one too ..awhile ago when I inquired) had no prob with doing a flush.

Online searches can be conflicting & non model specific.

[Jrs3800]

About the worst things these transmissions do is Overheat.... And if the trans has used up the additive package in the trans fluid then it will do the trans no good.. Its so hot/Warm here in Florida most of the time that I tell people to change the fluid and filter at least once a year... Down here its a great thing to keep the fluid clean..

There are parts that wear out with high Mileage or KM's...

4th Input shaft wears the teeth of the shaft... The reverse reaction drum wears out... Friction plates, bands... Parts just wear out... Other times they are cooked to failure...

But when you get to those High Miles or KM's anything is possible..

[96tsport]

Dunno why tranny pans (ones i've seen anyway..) don't have a drain plug.

I'm thinking of making one..

Just got my Chilton (gm service manuals are on the way..) & read that there are reusable gaskets out there.

[Jrs3800]

I have a friend that has taken a couple of pans and installed a plug... One is currently on my 95 Transport..... I love having that Plug as it sure saves a mess..

But on all of the other cars I work on I simply use a Plastic container from the Housewares department at Wal Mart... They are cheap and more than large enough for the intended fluid drippage...lol And did I say they were cheap...?LMAO...

The Orginal gasket that the van came with is reusable... It will be a stiff gasket with a metal band on the inside and rubber on the outside... GM intended this as a lifetime gasket.. And in most cases it can be used over and over as long as it has no nicks or breaks in the rubber part... If you have a bad one you can get a GM replacement for it, but search for a good price...

[LMP]

Just did it recently ('93 3800) ...dropped the pan, changed filter, reinstalled pan with original gasket, fillled up with 7 liters and I do not care about the 2 or 3 liters left in the converter..really not a problem. Tranny is 140000 km, about 90,000 miles, the 2nd oil change but my first intentional change, the actual first one was when one of the lines to the cooler failed and both lines then were replaced under warranty by GM.
I run the transmission in a very conservative manner, never overtorque the 4th not TCC, (shift out of TCC or to 3 on purpose) and the fluid would have been OK to run for many more miles, no odor, no serious opacity....and..no problem with heat in my place......

[Jrs3800]

This is my 1995 Bonneville 4T60-E... 3.06 Gear ratio attached to a 3800 Series II... This is what came out of the trans at 2 years.. I had added a Monster cooler a couple of years before this pic was taken.. The Cooler has done a lot in terms of keeping my trans alive as heat here in Florida is a tranny killer.. I used to do this at the beginning of the hot season and at the end of the hot season and the fluid would always have a brownish tinge to it.. In checking it with a scan tool before I ever added the cooler I was seeing temps as high as 230F in town with normal driving and the engine at 180-190F.. After I added the cooler the highest I saw was 180F and normal running temps were about 160F... Anyhow after 2 years on the cooler this is what I saw in the pan...


I now have a cooler on all of the 3800 cars in front of my house..lol

[96tsport]

Thing I like about the drain plug idea is after changing the filter & messing with all the bolts & stuff, it'd be reeaaal easy then to change the oil again after that ..at some point & probably get most of the old stuff out that was left from the prior change.

[Jrs3800]

I love that drain plug for exactly that reason.. And its the reason I put the plug pan on the Transport as I just rebuilt the trans.. Used the Trans Gel in the rebuild... I will dump the fluid soon and refill...lol

[96tsport]

Discovered tranny fluid can be drained from the pan with a small dia tube via the filler hole on some other trannies so guess the same could be done with the 4T60-E .

Also found out that one way of flushing is using the return line & putting it in a jug (or something), then while the car is running (some say best with tranny in drive to drain the TC, others use neutral) pour fluid in.

What's tranny gel?

[Jrs3800]

Originally Posted by 96tsport

Discovered tranny fluid can be drained from the pan with a small dia tube via the filler hole on some other trannies so guess the same could be done with the 4T60-E .

Also found out that one way of flushing is using the return line & putting it in a jug (or something), then while the car is running (some say best with tranny in drive to drain the TC, others use neutral) pour fluid in.

What's tranny gel?

Thats what you use on the tranny parts when yo do a rebuild... It thick almost like Vaseline... It Lubes and Hold pieces together..

When you dump the fluid its really a good idea to replace the filter..

[96tsport]

Originally Posted by Jrs3800

When you dump the fluid its really a good idea to replace the filter..

No question..

I was thinking of the secondary flush, or a flush in between filter changes & also no need then to install a drain plug. Sucking out the oil via tube also results in a cleaner removal of the pan. Guess flushing via return line with the engine running is a bit of a power flush & gets more junk out than with just draining.

Was mulling over what way to go about the drain plug & first thought was using a very small self drilling tapping type screw with an O ring..

Anyway ..found out that you can buy drain kits cheap. Suppose another way is drilling a half inch hole & you can get rubber plugs that tighten with a wingnut. Fwiw, here are instructions on draining via tube & flushing via return line (Titled - Flushing the system: a more complete method) ..for a dodge.

I learned that I can use about 6 or 8 ft. of clear vinyl tubing - probably only 1/8" or 3/16" ID. The type of low cost tubing you can get at your local home improvement or hardware store. What I've been using is actually the leftover home oxygen supply line from my late Aunt who had to use oxygen in her last year. She left us an abundant supply of this tubing. As for her nice Chrysler - darn it, that is another story......
I stick the clean tubing all the way down into the dip stick opening until it clearly is on bottom. Then I start a siphon by sucking on the tubing. You can easily see the reddish colored fluid moving up the tubing and towards you. When the fluid gets a few inches from the end you simply place the end into your container and the siphon action will do the rest.

[96tsport]

Originally Posted by Jrs3800

You will need about 6 quarts of Dex III compatible trans fluid for a 4T60-E.... This is at the least about half of whats in the trans...

Seems there's newer stuff out there that replaces Dex III. Unless I hear otherwise, i'll assume it's ok to go with the new stuff.