100,000 service and opinions....

[timmyjimmy5150]

Have my 07 denali at 97,000 miles.
At 100,000 miles I was planning on having the dealer change the plugs.
I already changed all for shocks/ struts....

What about the transmission fluid & filter? The dealer says to change it but all my buddies who work on cars and have high mileage vehicles say not to change it.... It just leads to more problems down the road. An independent professional mechanic shop also told me to leave it alone. Thoughts?

Anything else I should have done?
Thanks
Tj

 

[Goodinblack]

Should have changed the trans fluid a long time ago.

Trans fluid a A LOT of cleaning agents in it. Way more detergents then engine oil. Remember marvel mystery oil?

Also people used to run a quart of trans fluid in engines to clean sticking lifters etc.

Reason people say to leave it alone high mileage is because it can clean friction material off the clutch packs and cause it to start slipping.

One thing though is you should NOT have a entire flush done.
like from a t-tec machine. Etc

Whats the condition of the fluid like now?

 

[timmyjimmy5150]

The transmission fluid doesn't look too bad right now (97,000 mi). It's a little dark but not real bad.
The manual said to change it at 100,000 and earlier if under severe conditions, which my vehicle was not.
What you mentioned about the friction material being cleaned off the clutch plates and causing slipping out of gear, etc. is what all my mechanic friends said too. Exactly the same response from all of them and the shop as well.

I guess the tranny FLUSH is what would be bad? Would just draining the fluid and refilling with new be okay? No flushing involved. Or, just leave it all alone like so many others said.... Except the dealer of course...

 

[Goodinblack]

I would drop the pan change the fluid in the pan only and stick in a new filter.

Check for excessive metal / clutch material

I heard if some people even saving the fluid and filter it and reuse the old fluid. I would not do this imo

Also i never go by the manual for maintenance on super expensive items like a trans.

They don't care if your trans blows up out of warranty.

 

[AZwhitetrash]

The transmission fluid doesn't look too bad right now (97,000 mi). It's a little dark but not real bad.
The manual said to change it at 100,000 and earlier if under severe conditions, which my vehicle was not.
What you mentioned about the friction material being cleaned off the clutch plates and causing slipping out of gear, etc. is what all my mechanic friends said too. Exactly the same response from all of them and the shop as well.

I guess the tranny FLUSH is what would be bad? Would just draining the fluid and refilling with new be okay? No flushing involved. Or, just leave it all alone like so many others said.... Except the dealer of course...

Define severe conditions? In AZ we drop the pan and filter every year because of the heat alone, no matter how you drive. Just because you don't drive like GMs definition of "severe conditions" doesn't mean that it shouldn't be changed ALOT sooner! Also if the pan comes off, i don't care what truck it is, weld a drain plug in it! That way you can get the filter changed and 4+ quarts of fresh in, then at the next 3 ish oil changes, drain the pan and put 4 quarts in it...BOOM slow trans flush...like boiling a frog.