Trans fluid change on my 2007 suburban with 320,000 miles.

[MARK_VANDERBENT]

I bought a high mile suburban and the as far as I know it's the original trans, and I have no idea when the fluid was changed last. It is pretty dark but not burned. The truck shifts perfect and shows no signs of a problem. I have heard don't touch it, because new fluid may shock it into problems. I want to introduce a bit of Lucus, but fear this may clean out and dislodge sludge. What you all think?? Change it? Or. Leave it alone? Oh and yes I tow a trailer with this truck.

[BenK]

Experienced this first hand...bought a used 2000 Honda Odyssey with about 130,000 miles on it.

Had advised anyone who would ask/listen to flush their automatic.

Generally no problems...but...there is a chance to loosen or dissolve deposits (varnish is the main thing) on precision mating/sliding/etc parts. That will either float to make something stick and/or the mating/sliding parts no longer have the precision needed to do their jobs

On a trip to visit grandson in S Calif and loaded with tools to help SIL remodel their garage...coming back running down "The Grape Vine"...noticed the tranny shifting 'funny'. Lethargic both up-shifting and downshifting on the grades. After getting home...it continued to shift weird. Had the tranny's ATF flushed before the trip and all seemed fine for the weeks before that trip.

Mechanic said Odyssey's automatic is the weak system and he rebuilds tons of them. Mostly folks who load up to GVWR and/or tows. $3K cost and now know the automatic is the weak link from experience...

He says they tend to over heat the ATF and he has to clean the varnishes, but replaces valve bodies as that is where the main issue resides.

Now have an in-line ATF filter and he says to put in an after market ATF cooler...but there isn't enough room for that. At 18 years old...am considering getting another used Odyssey and think sooner than want to...

Suggest the OP just do the pan, filter and leave the majority of the old ATF in there....as long as it isn't too dark...nor smells of burnt ATF...do the white tissue test...

On high mileage trannies & ATF...it is 50/50 chance of creating a problem...or better stated...unmasking a potential failure now rather than it doing so by itself...

[Grit_dog]

Some mis info here, but good advice on the fluid change.
Honestly it’s flip a coin. I would change it. If it really is original trans with those miles it doesn’t owe you anything and I’d be surprised to see it last much longer.
If I wasn’t towing and just driving it around town I’d be apt to leave it alone but for work duty or long trips, you’re gambling with those miles anyway. Might as well give it the best chance for survival.

[ScottG]

IdaD wrote:
Just be sure you can get the fill plug open before you drain it. Don't ask how I discovered this nugget of knowledge.

:B:B:B
LOL, learned that one the hard way myself years ago!!

[IdaD]

Just be sure you can get the fill plug open before you drain it. Don't ask how I discovered this nugget of knowledge.

[MARK_VANDERBENT]

Just realized my post said 2007 ! Typo it's a 2009 6 speed. My bad!

[MARK_VANDERBENT]

Thanks for all the good advice.My truck does have the heavy duty towing package and trans temps are very stable and consistant.

[LIKE2BUILD]

Be aware the drain plugs on those pans are notorious for corroding in place. I tried everything under the sun to remove the drain plug on my ‘03 Yukon XL and all I did was strip the bolt head. It seems that’s a very common thing. If your burb is an old body style you’ll have to take the exhaust loose to be the pan off to change the filter.

KJ

[Bionic_Man]

rjstractor wrote:

Turtle n Peeps wrote:
What year is it? What tranny? A glide? A 350? 700R4? 4L80E? In any event you are going to have to drain it if you want a reliable unit. Better to find out now than on the road.

A 2007 is going to be a 6-speed. But I'm suspect of the whole post because according to RV.net Tow Vehicles lore, there is no possible way for a gas-powered tow vehicle to approach anywhere near 320,000 miles. Diesel is the only way to get over 250K!! 😉

I am pretty sure that it would still be the 4L60E. I don't think they went to the 6 speed until 2010 as standard equipment. 2009 it was an option.

Either way, I would go with the suggested drain and fill, not flush.

[rjstractor]

Turtle n Peeps wrote:
What year is it? What tranny? A glide? A 350? 700R4? 4L80E? In any event you are going to have to drain it if you want a reliable unit. Better to find out now than on the road.

A 2007 is going to be a 6-speed. But I'm suspect of the whole post because according to RV.net Tow Vehicles lore, there is no possible way for a gas-powered tow vehicle to approach anywhere near 320,000 miles. Diesel is the only way to get over 250K!! 😉

[Turtle_n_Peeps]

What year is it? What tranny? A glide? A 350? 700R4? 4L80E? In any event you are going to have to drain it if you want a reliable unit. Better to find out now than on the road.

[carringb]

I agree with avoiding a pressure flush.

You should drain and re-fill. Sometimes this can dislodge sludge or debris, causing near-immediate failure. If this happens, keep in mind it only accelerated the inevitable. Better find out before a long trip.

FWIW - I've gone to 100,000 drain and fills on my transmission. I'm a little over 450,000 and I'm a little over my 100,000 interval now. I just run the Napa stuff meeting factory spec.

[Fordlover]

My uncle's 2003 explorer has 350K on the original transmission, and he has them drain, swap filter, and refill. No special additives. Best of luck.

[FishOnOne]

Drain the fluid and change the filter. Do not flush and do not add any additives.

Good luck...

[Big_Katuna]

Hope you got it cheap. I’d be shocked if it hasn’t been rebuilt. I’ve had several Burbs and Silverados and rarely got 150k out of a tran.

I’d change it and be ready to rebuild it.

My sons 2002 Chevy 1500 just failed last week. 180k.