Transmission servicing??

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Moose912

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Hey guys,

I have a Denali XL with the 6L80E. Blah blah.

Question is, what types of trans services do you do and when? I only struggle with trans stuff but nothing else lol. Truck has 160 give or take. IIRC the history report showed a service at 75k. My initial thought is to do a full flush, cycle all the fluid out to new, change the filter as to not shock the system and cause an issue. Just don't need to be replacing a trans in this pig.

FWIW truck is mildly built...
 

swathdiver

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The fluid ought to have been changed every 45-50K miles, even less since the motor is pushing more horsepower through it. When my fluid had 36K on it, a sample was sent off to Blackstone Labs for analysis and they said that the fluid has about 10K miles of life left in it. Transmission was at about 150K miles at the time and a year or so since it was changed with a week of towing on it. Closing in on 170k now, still has the original filter in it, we've been doing fluid exchanges, no flushes.
 

alpha_omega

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What kind of driving do you do (highway, hills, fast, slow, long trips) and how much of that is done while towing something behind you? If you do plan on doing any heavy/long haul towing in the future, you might consider some upgrades while you have the trans drained. Not a requirement, but it may make the job a bit easier, that also is dependent on whether you plan on doing the work yourself or paying to have it done.

As @swathdiver mentioned, draining the trans every 45-50k is recommended. Luckily you at least had a 75k service do you know what that entailed, do you have the paperwork for it? I only ask because when I purchased my ‘11 Denali (56k) the stealership said it had a full inspection and all fluids serviced. Not even close…
 
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Moose912

Moose912

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So, typically more highway due to commute to work, but obviously there is in town stuff for errands. I dont really drive it hard. I pull a camper a few times a year. Right now its a 22' pop up, but will be a TT later this year. I cant remember if the service records even showed what was done aside from "Trans Service". I run a shop, and will be likely doing it here. However part of me want to have the stealer do it so when shit goes wrong it's on them. LOL.
 

alpha_omega

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In that case it sounds like you might not necessarily need any upgrades for towing (trans cooler, deep trans pan…etc).
Only problem with the stealership is getting them to either admit fault, or willfully correlate any resulting issues as being caused by the repair or negligence. The other issue being that it’s hard to find competent individuals willing to show up on time in order to earn a living. Kids now a days want manager wages with little to no experience or education.
That being said, if you want it done right…
If you decide to do the work yourself and are unsure of its current condition, I would suggest buying an OEM trans pan gasket when you buy your fluid and filter - or maybe order it before depending on the turn around time. It took me a couple days longer to get my gasket than it did the fluid/filter.
 
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Moose912

Moose912

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Yeah this is how I did my old Burb. I hate the dealer, especially since I have been running shops for 15 years and they've always been assholes. (Most of the time). That is my plan on this, pan gasket, filter, etc...
 

Robochop

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I also have an 09 Yukon SLT. How much tranny fluid does it take and are there a set of procedures? Other than just dropping the pan, changing filter and fluid. Should I be doing something else?
 

Foggy

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Do Not do a trans "flush" esp since it's been a long time between services...Drop the pan.
Inspect the pan for debris.. Clean everything. Put in a new Gm or Wix filter. And
fill it up with synthetic dexron 6 fluid....
Anything over about 110K is borrowed time on the OE torque converter clutch...
So at 160K you are doing something right (other than the service intervals !!)
 

rockola1971

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I would not do a flush. Just drop pan, replace fluid and filter. I would also be preparing for R&R bill for a tranny with 180k on the clock. Its just a matter of time now. Next month, 6 months from now or a year or so....its coming. Be prepared. Maybe you lucked out and the tranny has already been replaced or rebuilt before you go it.
 

donjetman

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Hey guys,

I have a Denali XL with the 6L80E. Blah blah.

Question is, what types of trans services do you do and when? I only struggle with trans stuff but nothing else lol. Truck has 160 give or take. IIRC the history report showed a service at 75k. My initial thought is to do a full flush, cycle all the fluid out to new, change the filter as to not shock the system and cause an issue. Just don't need to be replacing a trans in this pig.

FWIW truck is mildly built...
While doing a rear main engine seal job, I changed the 6L80 tranny torque converter, filter, and most of the fluid. We had just purchased the vehicle without mx records. It had 132k miles.

Now, 3+ yrs and 42k miles later (174k miles on the odometer), it's still going strong.

Soon take a sample and send it to a lab (JG Lubricant Services) for analysis again. Last analysis was done 2 yrs and 16k miles ago when the fluid had 26k miles on it. Analysis was good so I let'er ride.

This time, regardless of the results, I plan to drop the pan, change the fluid thats in the pan w/Dexron VI, and the filter (GM# 24236933) again. I'll also install a drain plug in the pan.
 

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