Servicing (or not?) Trans at 200k+ miles

[2010GMCYD]

My new-to-me '10 Yukon Denali has 210k on it. Records show the following done at 140k:

"Automatic transmission serviced
Transfer case serviced
Rear differential serviced
Front differential fluid flushed/changed"

Should I have the trans serviced again? At what mileage? I forget where I read but I remember someone saying to NOT service the trans again (ever) after initial service - sounds like bad advice!

I'm looking for some guidance on a maintenance schedule for a high mileage Yukon like mine.

Thanks in advance!

 

[Leevon]

There are definitely going to be opposing opinions on this. But the fact is transmission fluid has two main jobs; removing heat and friction. When the fluid is broken down it can't do that effectively and your transmission's life is shortened...same as engine oil. Do you avoid changing your engine oil when it's overdue, of course not. Now, if the unit is already worn out, and you replace the fluid it *may* bring some issues to light. But new fluid will not cause a failure, that's a myth. I have only had one failure after a flush on a high mileage unit at my shop, and the guy only owned the truck a few days so there is no telling what shape the transmission was in before the flush.

I'll add, if you have a 6L90 you need to be religious about fluid service. They don't like going past 40k or so in my experience.

 

[2010GMCYD]

There are definitely going to be opposing opinions on this. But the fact is transmission fluid has two main jobs; removing heat and friction. When the fluid is broken down it can't do that effectively and your transmission's life is shortened...same as engine oil. Do you avoid changing your engine oil when it's overdue, of course not. Now, if the unit is already worn out, and you replace the fluid it *may* bring some issues to light. But new fluid will not cause a failure, that's a myth. I have only had one failure after a flush on a high mileage unit at my shop, and the guy only owned the truck a few days so there is no telling what shape the transmission was in before the flush.

I'll add, if you have a 6L90 you need to be religious about fluid service. They don't like going past 40k or so in my experience.

Thanks for the reply. Been googling but it's not easy to find.... Is the 6L90 in a 2010 Yukon Denali AWD?

 

[donjetman]

Change your ATF and filter every 40k miles.

 

[wsteele]

Officially, the owners manual says change ATF every 100K miles unless you have "severe service" operating conditions. In "severe conditions" it says to change it every 50K.

Here is the definition of severe service according to GM:

(h) Change automatic transmission fluid and filter if the vehicle is mainly driven under one or more of these conditions:

• − In heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher.
• − In hilly or mountainous terrain.
• − When doing frequent trailer towing.
• − Uses such as found in taxi, police, or delivery service.

Looking at the severe criteria, it sure seems to me that just about any truck in the country would qualify for that ATF change cycle.

My transmission had to be replaced at 76K miles. I had followed the severe service guidelines of 50K as it had towed a lot (well under the max towing limits of my truck). I am not saying if you don't change your transmission fluid more frequently than what GM says to do, you will need a new transmission. I am just saying I change mine more frequently than GM says, because the guy who installed my transmission told me that is what I should do. All this guy does every working day of his professional life is rebuild/replace/service transmissions, diffs and transfer cases.

 

[Leevon]

Thanks for the reply. Been googling but it's not easy to find.... Is the 6L90 in a 2010 Yukon Denali AWD?

Should be yes, or 6L95. If you have a six speed. Our 2011 Escalade had it. I was religious about fluid changes and it went out at 112k though.

 

[Geotrash]

Thanks for the reply. Been googling but it's not easy to find.... Is the 6L90 in a 2010 Yukon Denali AWD?

You have a 6L80E in your 2010 Denali. 6L90 was only in the 3/4 ton models.

 

[swathdiver]

My new-to-me '10 Yukon Denali has 210k on it. Records show the following done at 140k:

"Automatic transmission serviced
Transfer case serviced
Rear differential serviced
Front differential fluid flushed/changed"

Should I have the trans serviced again? At what mileage? I forget where I read but I remember someone saying to NOT service the trans again (ever) after initial service - sounds like bad advice!

I'm looking for some guidance on a maintenance schedule for a high mileage Yukon like mine.

Thanks in advance!

Yes, as stated previously, change the fluid every 40K miles. I had mine analyzed at 36K and they said it has about 10K of life left in it and we only towed around town for about a week on it. 6L80 transmission. Change the other fluids too now as well.

 

[Charlie207]

Sorry to hijack this thread with a question, but are there succinct guides for the front/rear diff. oil changes?

I've seen a couple for dropping the transmission oil pan, and changing the filter (looks like PITA with the exhaust in the way), but am gathering parts for doing the three (trans., front/rear diffs.) for a free block of time.

 

[Geotrash]

Sorry to hijack this thread with a question, but are there succinct guides for the front/rear diff. oil changes?

I've seen a couple for dropping the transmission oil pan, and changing the filter (looks like PITA with the exhaust in the way), but am gathering parts for doing the three (trans., front/rear diffs.) for a free block of time.

I just take mine to the local lube tech to have my diffs and TC done. The reason is that the front differential is notorious for having one of the plugs be a total bhasthard (spelling to avoid the vice and virtue police's automated censors). Both of mine were - so much so that the techs brought my plugs out to me in the lobby to show me how hard he had to work to get them out. They replaced them with new plugs both times because the originals had been totally boogered in the process. Worth the money to me.