ss96kitten

This may be a silly or stupid question, but I wanted to ask the Gear-head experts on here anyway. I have put about 80k miles on my 04 Z71 in the last 3 years I've had it, which it now has a total of 160k miles-all highway miles due to commuting. My step-dad mentioned that we should probably flush the tranny and change the filter. However, another auto enthusiast friend of mine advised me that if I have gone this long without changing it...don't. He said that if a tranny has gone this long without the fluid being changed, if I flushed it now, it would most likely take a crap. He advised me just to make sure that the fluid level is full instead of flushing it. Don't have money for a new tranny, but would like to do maintenance so I can keep my truck in peak condition as long as possible.

Any truth to this?

TIA,
Jamey

ULTIMATEORANGESS

iTrader: (4)

i agree. i wouldnt touch it. it might screw something up.

red 95 t/a

Dont do it. With that kind of miles the rubber lip seals on the apply pistons are problly hard do to heat and age. You have some one flush (i.e jiffylube ) it could tear the lip seal or take a chunk out of it

Tim94gt

iTrader: (2)

I definitely wouldn't use a machine to flush it.

I would drop the pan and change the fluid/filter though.

bayer-z28

iTrader: (14)

Yeah.. Don't flush it. Too risky. That can have a tendency to loosen up any gunk that's holding it together.

I've been using Lube Guard Red stuff for a while with good results. It's just a conditioner. Had my last truck feeling like the trans was brand new. Just keep up with your scheduled maintenance.

wav3form

iTrader: (1)

I agree... don't do a power flush or whatever they call it in your neck of the woods. Drop the pan and change the filter and whatever fuild you can and you should be good.

bayer-z28

iTrader: (14)

^ Maybe drain the converter too. Some have drain plugs. IIRC.

RPM WS6

iTrader: (3)

That is what I would do too.

If you're going to do a complete flush with a machine, that should be done at least every 50k miles. To start that at 160k is just asking for trouble, IMO.

01ssreda4

iTrader: (96)

Exactly....

samson_420

iTrader: (1)

I would check to see what the fluid looks like. If it looks "too" dark, drop the pan, replace the filter and add some fresh fluid.

ULTIMATEORANGESS

iTrader: (4)

id be afraid to touch anything with that mileage lol. id just leave it alone.

senicalj4579

iTrader: (41)

I went to go see about getting a flush last summer/fall. The trans guy (who owns a LT1 camaro very nice) told me its not wise to do it. He said he might not even bother dropping the pan with so many miles on it. I asked if hes actually seen bad things happen from a flush and he confirmed hes seen more than enough evidence that a flush is VERY risky. So he talked me out of it and I dropped the pan,cleaned pan, changed filter, fluid, and gasket. Then I added a trans cooler and now im getting ready to drop the trans to put in the ss3600 so hopefully it hold up!

Tim94gt

iTrader: (2)

I blew up my 4l80E no more than 5 hours after getting it flushed.

The Trans was F'ed up prior and the dealer was being a pain in the *** about pulling it, so I told them to flush it and I'll be back in the morning. It was toast a few hours later.

71novaguy

iTrader: (2)

dont drain the convertor. I agree with the drain the oil and change the filter, but the new oil needs to mix some of the old left in the system to reduce the chemical shock.

ULTIMATEORANGESS

iTrader: (4)

i waited along time in between changes on a 3rd gen i had. fluid looked like chocolate milk lol. it started slipping shortly after.

Tim94gt

iTrader: (2)

This happened a few hours after I flushed mine @ 90K miles:



I'll never use a power flush machine again, I just drop the pan and change the filter then drain the cooler/lines as well. Fill it up and your good to go.

RPM WS6

iTrader: (3)

I've never had a problem with a flush machine, so long as the trans was flushed *at least* every 50k miles. Past 50k without ever being flushed, I would not do it.

I think the only people you'll find that have had immediate trans failure right after a flush are those with over 50k miles since the last flush.

Tim94gt

iTrader: (2)

My issue with it is that most people just flush it but never change the filter.

The flush loosens up **** that would otherwise stay put, some of it can't pass through the filter. The filter now has a restriction and the fluid circulates much slower, the tranny runs hotter and is more prone to failure.

I do agree that if it is done routinely it shouldn't create any issues, I just don't agree with not changing the filter. Ya, it cost more and you waste some ATF but Tranny's aren't cheap either.

In my case, My cooler lines were leaking so I brought it to the dealer had the cooler lines replaced under warranty. When they replaced them, they should have also replaced the cooler and radiator but GMPP did not approve the claim. There was a restriction in the cooler causing my Tranny to run hot @ 200* and would slip occasionally on the 1-2 shift. They insisted it wasn't slipping and the temp was normal even though it was running @ 120* prior to replacing the lines. I told them to flush it then I took the truck out plowing for 5 hours until it failed. They gave me a brand new Tranny, Radiator, Tranny Cooler and Lines courtesy of GM.

RPM WS6

iTrader: (3)

Ah, understood and agreed.

TurboStangJON

iTrader: (27)

After having an argument with a BG rep he decided to let me flush a truck and then take the pan down after the flush. Needless to say he lost the bet by a long shot on a 65,000 mile 2500HD. After flushing 15 quarts through the system the pan still had a significant amount of debris. My argument was that you can't get everything out of the pan because the filter won't allow that to happen. He stated yes it would and no debris or clutch material would remain within the system. Those flushes are a waste of time and money especially if you have a drain plug in the pan. My recommendation is to take the pan down, change the filter, and refill the trans. It's very risky in my opinion to flush anything with over 100,000. When I was 16 (now 28) and worked at a Valvoline we would get cars back all of the time after high mileage flushes. The writers at my old GM dealership hate me because I would unsell the flushes on many cars and sell the customer a cheaper pan drop/filter change. On all of my cars and trucks I've installed a pan that has a drain plug or it already came with one. This way every 10,000 miles I drain and fill the transmission pan and by the recommended 50,000 I've almost tripled what a flush would do.