auto trans - flushing vs NOT flushing!
 

Just a simple question/statement:

First - just for the record it seems on some web forums flushing auto trans is rated up there - like bob is the oil guy web forum... They even seem to use cleaners like AUTO-RX/etc..

But when I called several transmission places found in the TDR (turbo diesel register) pub. - ATS transmissions and Blumenthal Heavy Duty transmissions - both DO NOT recommand it at all.. ATS did say if I do flush it to change out the filter again after a short time to get the "junk" out that was pulled out during the flush.. But they generally do not recommand it..

As for Blumenthal - they state the same as ATS in junk and also if the transmission as been in service that if you do a complete flush the new fliud will be thinner then what the gears or used too/etc, etc - and can cause isues..

late insert:

Just a note and I think the answer around here is NO.. and I am not going to do it..

** as for the dealers - it seems they see $$$ when you drive in and TRY to tell you it is BEST to do it...

Trans fluid
 

My friend runs a transmission shop and his recommendation is to flush very 10,000 miles like clockwork or when you run it really hot. If you don't do this then his recommendation is not to flush the oil but just change the filter, and refill the level to the proper level.

His reasoning is old oil will build up varnishes and glazes on the parts and the complete flush will act as a solvent to these varnishes and glazes. However the new oil won't dissolve the varnishes and glazes all at once causing erratic operation and possible failure.

L8r,................dogger

Your comments are part of the puzzle

like everything else - one seems to get a diff answer on the same question from 10 diff sources.... One reason I asked top dogs like DTT and ATS and other shops - all said NO!.. I have been given your comments/answers before.. Nothing against your comments.... This is one reason I started asking questions!!

ps: I was/am just trying to decide which way to go... right now I am seem to be going the DTT and ATS route..

I am sure your friend would like to do a tranny flush every 10,000 miles he would make good money doing that.I do not flush the tranny and never will.

Do a search on this topic and you'll find the answer to be a resounding 'No'. Can't remember the particulars but the reasons for not doing are far more convincing than the ones for flushing.

I came away saying, "mine will never be flushed."

Edit: take a look here, read all of it, and then do a search on the site for "transmission flush" 'cause there is more.

http://dieselram.com/cgi-bin/ultimat...;f=29;t=001723

I'm getting mine serviced tomorrow - no flush. Just drop the pan and change the filter. A flush can stir up particles that get into places they shouldn't be, especially if done wrong.

Ok - I don't think I will ever do a flush.. But I forgot to list the other part of the question..

Does anyone ever put in a "cleaner" like AUTO-RX or other - that is "said" to clean the varnish/etc and clean the plates ?? Not that I am to do this! I may have to start a new thread for this question...

On my CTD I changed the pan at 20K. While it was open I changed the filter.
At 30K I just drained the pan (new pan has a drain plug) and refilled. I'd been towing heavy and some hot.
I'll probably go to 50 or 60K before I touch it again, not sure if I should just keep draining the pan or pull a hose and let it pump everything out.

On my Caravan I serviced it at 60K and then asked a shop to do it again at 110K. They declined saying that it was past due and "adding new fluid now is guaranteed to burn up your trans". So I did it myself - dropped the pan, changed the filter and then pulled a hose to pump fluid until it ran clean. 2K miles and it has not burned up yet...

The people who know these trannys say additives are a bad idea. I would avoid them.

I would have to agree with you. but don't ask me then why the questions [eyecrazy] I am just shop talking..

ps: One funny thing is that DTT said NO to ATF-4 due to the added friction modifiers.. "and they knew I have a dodge 48RE trans" [eyecrazy] I reminded them I had a 48RE ?? hmmmm..

DTT also stated they change the trans fld at 12,000 miles!! I know they have some of the best trans.. but is 12,000 changes like a insurance policy for them [deadhors] .. Just joking!!

This has me very confused. My dealer changed the fluid at 15,000 miles, per the manual recommendation. What is "changed"? Flushed? Or is it just drained? I don't understand the differece.

Are you saying we should NEVER change the fluid?

flushed meaning connecting a pump/machine and using pressure to "back flush" the lines..

From reading the Trubo diesel Register Pub. - the best way if you with to get most without flushing is to pull pan and then disconnect the return line up front by radiator (and use rubber hose to drain into bucket)and then start engine "for a few sec" until it stops coming out.. this way you got some 99% without flushing - and more then just draining...

ps: the flushing is said to "possible" cause issues by pulling junk to places it should not be.. valve body/electronics/etc..

i just had my filter changed a new trans pan put in and a "flush"

but all the flush was that the trans guy disconnected the return line off the trans and started the truck and let it run until he seen the new bright colored atf4 come out

I've done 'full flushes' on my own on the cars, and have also had it done, but it seems that it means different things to some.

When you drop the pan, change the filter, bolt it back up and then refill, you get maybe 2/3rds of the fluid. If you're doing it to change the fluid then it seems that you'd want to change most of the fluid. If you have a real filter and not just a screen, it makes sense to change it once it awhile.

I was pressed for time a couple of weekends ago and needed to change fluid to a cleaner out, so I had it done. I had my own fluid as most places like using a basic fluid and adding something to 'convert' it, something that I don't like. Everyone seems to use a 2 tank 'T-Tech' ? machine or something, where you connect one tank to the 'out' cooling line of your tanny, the other tank to the 'in' cooling line, add new fluid to the 'in' tank, turn the engine on, and let it idle until all of the new fluid is sucked in and an equal amount of old fluid is dumped into the other tank. A lot of shops talk about back flushing and such, and although the machines might be capable of that it seems that they'd be fighting the regular flow of fluid thru the tranny out to the cooling lines to the cooler and/or radiator and back into the tranny. You'd have to run the engine and tranny backwards for 'back flushing', unless I'm missing something, and I guess I'm always missing something as I've not seen anyone do it; they just hook it up and let it run.

I did the other car myself, where you get a half dozen or so empty milk jugs, mark a 3qt line on each, stage the new fluid close by, unhook the fluid line going into the radiator, connect a short length of hose to it, put the other end of the hose in a jug, have someone start the vehicle and put it in park or neutral as desired, let 3 qts drain into the jug, stop teh vehicle, add 3 qts, fill another jug, refill, etc. It takes about an hour to do, provided you don't make a mess by knocking over a jug of fluid, spraying fluid all over, etc. :^)

Anyway, when I do a 'full flush' I run the tranny capacity thru it, which for the cars is about 16 qts or so. So, this type of 'flush' is merely using the normal flow of fluid to change the fluid, all of it instead of 2/3rds of it, no evil spirits in the tranny are disturbed, and it works just fine.

I have done hundreds upon hundreds of transmission services in my life as a tech. and talked with many rebuilders on this and I feel that if you service your transmission regularly and do not overheat/work it there is no reason to use a flush machine.

Many vehicles do not have provisions for draining the TQ (like they used to). I feel that the examples given (removing a trans cooler line, starting it and adding fluid) are perfectly fine if done properly. If your transmission has a drain plug on the pan already there is no problem with draining just the pan and adding fluid periodically...like every oil change if you want.

On my wifes Acura MDX is does not have a filter to change and only holds 8 or so Qts. of fluid. I drain and fill it every 15K. I will do the same on my truck and by doing this the fluid should never get bad.

What I have seen and been told is that when a tranmission is neglected, not service, overheated etc. it will build up a glaze and varnish on the clutch plates. The glaze & varnish on these plates can break-up and can cause all types of problems if a full on service or flush is done on a neglected trans.

What usually happens is that Joe customer neglects the trans., it gives a hiccup and he decides to give it its first service at 85,987 miles. The tech drops the pan and says to everyone in the shop "hey guys take a look at the mud that came out of this one" everybody laughs in the shop and the tech changes the filter and finishes the service. He test drives it and everything is working fine. Joe customer picks up the vehicle and drives home. A week of driving goes by and the transmission seems to be acting funny again. He brings it back in saying that it all started after that transmission service/flush was done....go figure! Now he is going to tell everyone that the flush damaged the transmission. Well I don't think so......The neglect damaged the transmission!!!