Transmission flush

Local dealers are promoting a transmission flush service. I am leery of this because I feel that this will stir up shavings and clutch wear particles and circulate through automatic transmission. I feel better to drop pan, change filter and add fluid to top off (because even a flush does ont get all of the old fluid out)
Anybody got opinion on this?

I agree with you.

Those "flush" machines are for LAZY mechanics.

Allan

Hey now, while I do agree a flush is not the best for every vehicle, I have brought more then a few back from the dead with a flush. I believe if they are done regularly, a flush is good maintenance. Doing a flush every 50-75k for a daily driver or every 30-50k for a heavy puller is a good deal, at least in my experience. It's when that heavy puller is rounding 150k and it's never been done is when things go bad. My experience includes my 2007 dodge 3500 diesel with a 6 speed auto. 310,000 miles, loaded for half of those miles. Trans has been flushed every 50k and filter changed every 100k. The trans is original and operates flawlessly.

Just my 2 cents
Casey in SD

if it's a low mileage vehicle maybe, but not on one with high mileage, new fluid is slippery and can cause slippage in a high mileage trans, most honest tranny shops will tell you this, almost every time I changed fluid I started having problems, friend has a flush machine at his shop, it sits in the corner collecting dust

My other concern is: If you cant get all of the fluid out, then how about the cleaning solvent that winds up in the torque converter, etc?
The car is a 2009 Pontiac G8 GT with 82K miles, mostly interstate/long distance miles on it. 6- speed auto.
By the way, GM does not even have a dipstick on this trans, claims 100k mile service interval w/ normal use.
PS I have had my trans on my 03 7.3 Ford Powerstroke F250 done every 30-40 k (filter/top off fluid) No problems, (fluid looks/smells ok)
Just cautious re flush process.

I've had them flushed out but can't say it made a difference.Around here it's a $150.00 bill.
Last year I changed the 2000 ck.I do 40,000 miles on a filter and fluid.It looked as good as new and no junk in the pan or on the magnet.It was the second change sense the flush.
If you aint been thru a flood or have got it hot enough to cook burgers on it ,I wouldn't worry about it.
An old mechanic once told me IF IT'S DARK PINK AND DO'NT STINK leave it alone.
Good Luck.

Agreed.


My understanding is there are two types of flushes. One lets the transmission pump suck in the clean fluid and pump out the old fluid - usually they start with a gallon or so of cleaning solvent then switch over to the clean transmission fluid. This changes 100% of the fluid and allows the transmission to function as it would in normal operation. It also "wastes" a couple quarts of fluid in the process.

The other is a power flush the forces the fluid through the transmission - some even advertise a "reverse" power flush - I would avoid both.

If your transmission is so full of trash that the mere act of adding clean fluid "plugs" the filter (actually a screen in most cases) you needed the transmission rebuilt anyway. Pulling the pan might be best on a high mileage transmission of questionable condition just to see what has been deposited in the sump pan. Not that it does a better job but you know if you need to skip changing the fluid and go straight to the overhaul.

Most transmissions have only a screen for a "filter". A transmission in good condition the clutch packs and other areas will wear so that the particles ar so small that they will pass through the screen. When you have "chunks" that the screen catches the clutches are breaking up and you need to do more than change the fluid.

On a higher mileage transmission these particles will act as grit in the worn clutches to get the last little bit of wear out the transmission - in a lower mileage transmission this "grit" causes more wear on clutches that are in good condition. Basically if a transmission is on its last legs changing the fluid will hasten its demise. Changing the fluid as recomended (every 30K to 60K as the manual will recommend) will make it last much longer.

Gm automatic transmissions haven't used "screens" since way back in the seventies.

They use a micron paper filter, which allows nothing but fluid to pass.

Allan

You nailed it. I forgot to mention the different types of flushes. I agree the forced flush is bad. My machine is the type that lets the trans do the work. An average transmissions holds around 3 gallons of fluid. My machine holds 4, so yes, I run an extra gallon through in hopes of getting all the the old dirty fluid out. If a vehicle comes in with 150k and it's never been done, I won't do one. Drop the pan and change the filter is as far as I will go. If a vehicle comes in with a problem, 80% are cured with a flush. I've lost count of vehicles that come in missing overdrive, I flush them and walla, OD is back. Is it a permanent fix? Absolutely not, but my customers are very happy I bought them some time.

Casey in SD

Actually they've used mainly felt since the early 1970s but its designed just like a screen. To "only let fluid past" would take a huge amount of surface area that most transmission filters just don't have.

Well, I'm not gonna get in a pizzin match with ya that's for darned sure, but I'm tellin' ya, they DON'T USE "FELT" and NEVER HAVE.

But Hey! What do I know?....... I've only been repairing automatics since 1959. :>(

Allan

Longest life is doing the recommended service- fluid/filter change at whatever mileage, 20,000 to 40,000 miles. BUT, we all know most transmissions in use by non-commercial driving public are lucky to get a 25,000 dealer service for warranty and don"t get "serviced" after that until slipping, fail to shift, or the fluid check shows black and burned. Commercial users like some of the rental companies have drain plugs in the transmission pans- every other engine oil change the tranny fluid gets drained also-this gets about 1/2 the old fluid out at least- and fresh fluid added to fill is done at 1/3 the long service interval, 10,000 miles instad of 30,000. X Hertz F250 van made into light tow truck had this type pan, my old Kaiser DJ5 X postal also had pan drain plug and postal shop worker confirmed that the tranny pan drain was regular service, the "surlpus" DJs had maintenance logs and when checked showed the engine and tranny drain mileage- the rear ends also had changed oil logged. Ford Crown Vics and now Taurus option has the drain plug in tranny pan available if ordered by public- this was one of the parts of police/commercial package for designated fleet sales -like rentals in Texas- for many years. Other part of commercial package for the trucks/vans- a external added oil filter in coolant line, same 10 micron with a clog bypass as engine got on van with clearance, the small filter is supposed to be on the Taurus commercial. GM powerglides in early commercial use also had the drain plug- part of the commercial package in 1970s for delivery vans used in Chicago and the cabs with Chevy engines I drove then. Tow package catalog from a conversion outfit/tranny rebuilder has the pans with plugs added, plug kits to put in your own, and the external oil filters for aftermarket/
upgrade use-- local Ford dealer has the catalog and will do a quick upgrade on used vehicle that customer wants to do a boat tow or commercial haul, delivery with what was a standrd package vehicle- a Ford gets done on day of scheduled service or delivery, a other market vehicle takes 3 days to schedule to make sure the parts are there from order- Ford kits is a couple on the shelf already. The Ford minvans getting abused sometimes get this upgrade on tranny change, the new little Transit high roof model is supposed to come from factory with drain plug in pan- not sure about the external filter. NAPA has tranny pan drain plugs kits on shelf or can be ordered for many vehicles. Allison trannies on bus and semi tractor come with drain plugs. Old technology, simple to used during engine oil change, takes maybe 10 minutes to drain 1/2 tranny fluid and top up after. And if you have a drain tank with a filter, can use the drained tranny and engine oil in fuel tank of diesel truck- I know of a couple shops that do that and Hertz was supposed to do it also along with Ryder. RN

You need to tell Fleet Guard that, apparently they don't know what they are building.

http://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/LT15201.pdf

I think what your talking about is SPX Filtran, which is a felt material. I just looked at a WIX filter for a 4L60E, which has got to be the most common GM filter, and there is NO screen.

From SPX Filtran's website-

The 1980’s saw much technological advancement, and transmission filters advanced from screen filter technology to more advanced filter media, integrated into the transmission system. Filtran led the industry using advanced non-woven polyester, known as felt media, and introduced Sealed-Seamed Zero Leak™ technology.

I have an 06 and am curious what trans fluid to use on its first change. Only has 36k on it.