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Change Trans fluid or not?

6K views 41 replies 11 participants last post by  Submariner409 
#1 ·
My 2000 SLS has 170,000 miles and unless the previous owner changed the transmission fluid before I got it 3 years ago with 40,000 miles on it then it has never been changed. It runs great but it has been bothering me for a while as I have been thinking I should change it. I really don't trust transmission shops, I know that most jobs like fluid changes are usually given to the apprentice or green mechanics. Is it worth taking to the dealer? Are they likely to try to suck it out and replace or should I ask for them to drop the pan and clean the screen? Any advice? Thanks
 
#3 ·
-----------------------------------
SO much BAD information here - WHERE do I begin -

1 - check the fluid -
look at the color is it red/pink - like cherry Kool-Aid?
or nasty burned dark brown?

2 - smell the fluid - is it really stinky?
or mostly odorless?

3 - check the TRANS FLUID OLM -
it will display a % of TRANS FLUID life remaining -
 
#4 ·
Personally, I prefer to change the transmission fluid every 80K-100K miles, or every 10 years.

There is certainly no "point of no return" as far as trans fluid changes go. In reality, the point of no return is the instant a part is put into service. At that point, with use, it will eventually fail.
 
#11 ·
basscatt said:
-----------------------------------
SO much BAD information here - WHERE do I begin -

1 - check the fluid -
look at the color is it red/pink - like cherry Kool-Aid?
or nasty burned dark brown?

2 - smell the fluid - is it really stinky?
or mostly odorless?

3 - check the TRANS FLUID OLM -
it will display a % of TRANS FLUID life remaining -
Wrong kiddo. Cycling the debris (metal) accumulated in a transmission especially for 170k is going to cause more issue then prevent.

Ergo bad idea.

Op drain and fill if its really bothering you but do not even consider a flush.
 
#17 ·
----------------------------
Wrong kiddo
so - let me get this right -

MY suggestion of checking the trans fluid color - smell - and TRANS OLM -

is WRONG?

REALLY?

and YOUR blanket statement of " don't change it" -
based solely on 170K miles on the odometer -
without any history -
without even looking at the fluid -
is GOOD information?

REALLY?

-------------
I never suggested to flush it -

I never suggested to exchange the fluid -

I DID suggest to INSPECT the fluid -
and YOU say that is WRONG -

THAT - is BAD ADVICE -
 
#18 · (Edited)
If you're worried about transmission fluid temperatures, there IS a transmission temp sensor in the 4T80E - it's a go/no-go affair and it turns fans on to FAST at 304 degrees - that's right - 304 degrees. Worry more about your next latte' than about transmission temperatures.

Because the transmission fluid cooler (in these FWD cars) is in the end tank in the return (cool) side of the radiator, fluid usually runs at about 190 - 210 degrees - right where it's supposed to be (EDIT: when everything is warmed up and stabilized).

The owner's manual gives insight for transmission fluid maintenance under different operating conditions. Transmission fluid is not subject to anything like the contamination that engine oil experiences, so transmission fluid can run for a very, very, very long time.
 
#19 · (Edited by Moderator)
If you're worried about transmission fluid temperatures, there IS a transmission temp sensor in the 4T80E - it's a go/no-go affair and it turns fans on to FAST at 304 degrees - that's right - 304 degrees. Worry more about your next latte' than about transmission temperatures.

Because the transmission fluid cooler (in these FWD cars) is in the end tank in the return (cool) side of the radiator, fluid usually runs at about 190 - 210 degrees - right where it's supposed to be.

The owner's manual gives insight for transmission fluid maintenance under different operating conditions. Transmission fluid is not subject to anything like the contamination that engine oil experiences, so transmission fluid can run for a very, very, very long time.
Holy Stuff!!! 304*!!!!
Thanks for the good info too!!!
 
#20 · (Edited by Moderator)
basscatt said:
----------------------------
Wrong kiddo
so - let me get this right -

MY suggestion of checking the trans fluid color - smell - and TRANS OLM -

is WRONG?

REALLY?

and YOUR blanket statement of " don't change it" -
based solely on 170K miles on the odometer -
without any history -
without even looking at the fluid -
is GOOD information?

REALLY?

-------------
I never suggested to flush it -

I never suggested to exchange the fluid -

I DID suggest to INSPECT the fluid -
and YOU say that is WRONG -

THAT - is BAD ADVICE -
Title says change trans fluid or not, I made a statement on that subject not your suggestion to check the fluid. Common sense would deem you would check it every so often but since its a sealed unit (bar the dip stick) unless your leaking it or your rad side tank busted and its mixing coolant and trans fluid it should never be low. Remeber a trans doesnt use oil like a motor (especially the fwd N*s and the 3.6 nightmare motor does). Perhaps you should investigate the difference between CHANGING fluid and CHECKING fluid levels...

Goodluck!
 
This post has been deleted
#21 ·
In anyone's book, 170,000 miles is a bit much, even for transmission fluid.

A GM dealership will do a machine-operated transmission fluid exchange - all the old fluid is removed and replaced with the new recommended synthetic DEXRON-VI, in exclusive GM use since late 2006. That service is non-invasive and is usually enough for a transmission in good condition. With retail oil pricing and labor rates I would guess that service is now pushing $200 or maybe even +.
 
#22 · (Edited)
The following is neither good nor bad information, just fact from actual observation:

New fluid can (not will) "clean off" old, charred or brittle (from heat) clutch material. The forward clutch plates are especially prone to this as they are the hardest ones in the unit. Since there is no way to see the condition of them, it's a crapshoot.
Will not definitely happen but possible.
 
#23 ·
The following is neither good no bad information, just fact from actual observation:

New fluid can (not will) "clean off" old charred or brittle (from heat) clutch material. The forward clutch plates are especially prone to this as they are the hardest ones in the unit. Since there is no way to see the condition of them, it's a crapshoot.
Will not definitely happen but possible.
I have to admit. I was ready to call BS on this, but then I found this article. I try to stay open to new ideas. Maybe it's where you saw it too

http://articles.chicagotribune.com/2000-03-12/travel/0003120058_1_transmission-fluid-atf-oxidation
 
#26 ·
I called the Dealer, the service advisor suggested dropping the pan and changing the fluid, he advised against exchanging the fluid, said with high mileage the pressure changes created when exchanging the fluid could be harmful. They want $210. I might let them do it so they can check and advise on my oil leaks as well.... Thanks for the replies..
 
#29 ·
The Tech Tips section has a post about so called "transmission flush" procedures. There is no such thing in the factory service manual. It could (and has) throw metal debris into filters and valves causing premature failure.

The proper way to service the fluid in the transaxle is to drain and refill. There are a couple of filters that are reusable as well as a hidden plug.
Alternatively, some (including myself) have used the trans pump to pump out the fluid using a hose and a bucket. After that, one could lift the car and undo the trans bolts and pour the remainder of the fluid like oil. Clean the filters... then refill with fresh fluid (Dexron VI) the same amount that came out!
 
#31 ·
FWIW, in the OP's car the GM labor rate to exchange fluid, including a pan drop and clean, is 1 hour.

So, at a labor rate of $100/hour (metro area, common) and using 14 quarts of fluid at $10/quart (dealer), then $210 is a fair price for the service.

......... and the buyer would have an invoice, service record, and place to go if problems arose, especially within 30 days of the work.

DEXRON-MERCON-VI is now an almost universal automotive transmission fluid.............. and it's not cheap. Glad I have 3 cases of old DEXRON-III for the log splitters ...........
 
#41 · (Edited by Moderator)
Um

What ever serious repairs that are done to my Deville are done by Mechanics

The only thing I know how to do on my own is change the oil... And I'm not really good at that

There's no way I would attempt to do Any Serious Repair or Modification on my car myself...

I may come to this forum with dumb ideas or questions but I come ASKING THE PROS for their Advice and Knowledge...

I've Never claimed to be a Mechanic or Know Anything

It's guys like me this Forum Truly Helps, otherwise u might be driving on the same road with an immanent catastrophic event
 
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