The million dollar question

[Stresst]

Do I replace the transmission fluid and filter or not in my recently purchased 07 Denali with 86K or not??? I bought this truck less then 1 month ago so I dont know previous history but what I do know is this truck has to get me by for at least the next few years......

So what do I do?

 

[sumo]

Id do it if i couldnt find any info about a trans service. Fresh Tranny fluid will never hurt your ride as to old worn out fluid and filter that could. when you say just purchased, you mean private or dealer used?

 

[Stresst]

Id do it if i couldnt find any info about a trans service. Fresh Tranny fluid will never hurt your ride as to old worn out fluid and filter that could. when you say just purchased, you mean private or dealer used?

There is an old myth that replacing the fluid will destroy the clutch plates....over the years I had 2 transmission failures several months after having them serviced. Just a coincindence? IDK???

I just purchased it dealer used but now thinking about it I have an extended warranty so maybe I will do it.

What fluid is recommended?

 

[sumo]

Its the latest Gm came out with. Not cheap. If it been serviced at a dealer then they will be able to tell you If it was done or not at the Pre delivery inspection. Oh and the Myth theory is just that. A myth

 

[Stresst]

Its the latest Gm came out with. Not cheap. If it been serviced at a dealer then they will be able to tell you If it was done or not at the Pre delivery inspection. Oh and the Myth theory is just that. A myth

I bought it at a used car dealership...... and not about to bring it to the dealer for tranny service as its 300-400 bucks!

 

[lowexpo]

Holy crap! It was only $115 to have my Allison serviced at the dealer.

 

[THE YETI]

GM vehicles are built to go maintenance free for 100k miles aside from oil, gas, brakes, etc.

Everything else is "recommended" service.

 

[Stresst]

Holy crap! It was only $115 to have my Allison serviced at the dealer.

I went to the dealer the other day to pick something up so I stopped by the service dept for kicks and asked him about changing the fluid in the diffs and transfer case 499.99, coolant was 179.99. They are nuts!

---------- Post added at 07:46 PM ---------- Previous post was at 07:26 PM ----------

GM vehicles are built to go maintenance free for 100k miles aside from oil, gas, brakes, etc.

Everything else is "recommended" service.

I seen something that said its required at 50K for heavy/severe use which imo falls under driving in the city. I have 86,*** already... in the next few weeks I would like to take care of it (or when I get some extra cash).

What is the deal with replacing brake fluid? I have to be honest I NEVER did on any car I owned.

 

[BOSS]

There is an old myth that replacing the fluid will destroy the clutch plates....over the years I had 2 transmission failures several months after having them serviced. Just a coincindence? IDK???

Not coincidence but what were the mileages on those 2 vehicles, high I suspect?

You can skip the stealer and go to a Kwik Lube place for a fraction of the price. I would do it at 86k if it were my vehicle, in fact I did. BUT......BUT you must keep up the fluid change. After 100k, if you let it go another 100k without swapping the fluid out, forget it.

When you change the atf, you are swapping out the old fluid for fresh fluid which changes the dynamics of the trans and pressures exerted and required for how it functions. In older trannys, tiny particles of metal shavings and such build up in the trans, and your trans gets accustomed to them. If you dump the atf on an older one, you rid the trans of what it has been accustomed to and expects for frictional properties and pressure. Thats why you get trans failure swapping out 150k-200k fluid.

B

 

[Stresst]

Yeah they had very high mileage.....

Thats what I planned on doing, just having a small shop to replace the fluid and filter. Call me cheap but the last time I brught my car into the dealer for service was years ago when I used to lease! lol

After this tranny service how often should I do it? I dont drive more then 10k per year but NYC traffic really takes a toll.

 

[THE YETI]

I seen something that said its required at 50K for heavy/severe use which imo falls under driving in the city. I have 86,*** already... in the next few weeks I would like to take care of it (or when I get some extra cash).

What is the deal with replacing brake fluid? I have to be honest I NEVER did on any car I owned.

If it was "required" then GM wouldn't have a 100k mile warranty on their drivetrain. They would have a 50k warranty. These vehicles are intended to go maintenance free (aside from oil changes) for 100k. and that was a direct quote from someone more powerful than I'll ever be at GM.

 

[fire730]

Thats what I planned on doing, just having a small shop to replace the fluid and filter.
After this tranny service how often should I do it? I dont drive more then 10k per year but NYC traffic really takes a toll.

Yes just change the fluid and filter and make sure they use Dexron 6. It's a synthetic version of the Dexron 3 they were using in the older models. I think they started using 6 around the 05-06 models. And from what I heard 6 can be mixed with 3. As far as service intervals after I would say another 50 k miles should be fine but the fluid will tell the story. It is synthetic and even traffic isn't as big of a deal since you have a truck with Efans. They are so much more efficient than older trucks with clutch fans. Monitor your tranny temps for awhile and see what kind of numbers you are running when you are in traffic as opposed to constantly moving to see if the traffic should e a concern or not.

What is the deal with replacing brake fluid? I have to be honest I NEVER did on any car I owned.

Brake fluid is hygroscopic so it absorbs moisture. Which in turn lowers the boiling point so when it is over heated the moisture in it could evaporate and cause "air pockets" which lowers the pressure that gets exerted on the fluid.

Would you tell a difference if you had the fluid changed? Probably not but in an older vehicle or race vehicle it could make a difference.

 

[Stresst]

Thanks