08 Transmission Flush

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techbiker

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This is how 'most' of us do it. Use the cooler line to the radiator and a 5 gallon bucket. You can pump out the pan first, so if you're dropping it to change the filter it's empty already.

I only dropped the pan without pumping out once... One of my worst mistakes ever. ATF dumped all over my head and the garage floor! My hair was still greasy after a shower.
 

KATfishing

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try running a carfax on it if it was serviced at a dealer or national company it may show when it was done last.
I agree! Bought my 08 denali at 80K. Ran carfax and immediately saw that dealer had serviced transmission and other fluids at 65K. Helped to inform my decisions going forward. I'm at 126K and going to have fluid/filter changed by shop. Still under warranty for another 6K, so if something shows up during/after service, at least I have a few thousand mile grace period.
 

steve45

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I don't believe in changing transmission fluid. If you've waited this long, you'll probably end up with seal problems after they soak a while in new fluid.

I've had a number of transmission failures--NONE of them fluid related. Don't waste your money.
 

Kendall69

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This may be in wrong section feel free to move....
I have an 08 Tahoe I bought last year in Dec. I keep the oil changed every 3000 miles but I don't know if the trans or diff fluids have ever been changed. It has 144k on it so my question is what does everyone recommend when it comes to trans service. Just filter change and new fluid or new filter, flush and new fluid?

Appreciate any info you all have for me.

For me, I change every fluid on every vehicle I purchase it the day I bring it home - including new ones, bye especially used ones. New ones I won't do the tranny or coolant but front and rear diff's get changes, the engine gets changed, transfer case gets changes. I want the synthetics that I use in my vehicles and never trust what was put in usually it's the cheapest stuff made. So who cares if they did or didn't do it, do it anyway with good synthetic fluids and do it right. Also, change the filter. I have never heard of a vehicle being damaged by too many fluid changes too often.
 

Big Mama

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My trans guy has a rule. If the trans is giving you trouble change the fluid and filter. If not flush and fill. I’m at 118k and did a flush. There’s a hybrid method of drain and fill then drive and repeat until fluid looks right. I’ve never seen this come out right. A drain only empties the pan not the converter that has the majority of your fluid.
 

guy from norcal

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I don't believe in changing transmission fluid. If you've waited this long, you'll probably end up with seal problems after they soak a while in new fluid.

I've had a number of transmission failures--NONE of them fluid related. Don't waste your money.

I would rather spend $ 200 on new fluid,filter, and new pan with drain plug, rather than do nothing, And wait till it blows up on you. now your out a few $ thousand.
 

miatawnt2b

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Youtube Yukon transmission flush on youtube. There is a method of pulling the cooler hose off of the trans cooler and using the transmission's built in pump to flush all the fluid so you can get a 100% change. Basically refill 2l, pump 2l, repeat until fluid runs bright red. Works really well.
 

GranPrix

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Kinda on topic but for those of you that dropped the pan and used a new gasket, by any chance did you use any RTV on the pan?
 

Jason_S

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Kinda on topic but for those of you that dropped the pan and used a new gasket, by any chance did you use any RTV on the pan?

Not normally. That being said, I have used dabs of RTV or grease to help hold the gasket in place until I can get the pan in place and a couple of bolts started.

The only time I remember using RTV on the entire gasket was because the gasket surface on the transmission itself had gotten a bit gouged in a couple of spots and we couldn't get the gasket to fully seal. Even then, we only gave the transmission side a very light application.
 

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