ATF Lab Results, Dexron VI, 43k miles on fluid

[donjetman]

I recently changed the ATF & filter. I took a sample with a JG Lubricant Services used oil analysis kit. They use Polaris Laboratories. Sent it in and 5 working days later here are the results. This is the same fluid and filter as before (see result #1).

Lab flagged the viscosity of 5.6, so I called Tom Johnson of JG Lubricant Services. Tom is co-owner of JG Lub. He spent 30 yrs with GM/Allison as a fluids engineer. He said when viscosity gets to 5.5 they recommend changing the fluid. When viscosity gets to 5.0 bushings etc start to wear. So my timing this fluid/filter change worked out good. Not too early, not too late.

Tranny has 174k miles since new. 43k miles ago, while doing the engine rear main seal job, I replaced the original torque converter as a preventative mx item. That was the last time I changed all the fluid and the filter.

 

[gooffeyguy]

So the factory severe maintenence schedule is spot on in your case at 45k miles

 

[Geotrash]

Thanks for sharing, Don. I will do the same when I change my fluid next.

 

[swathdiver]

That jives with my fluid analysis too.

 

[m1949]

I recently changed the ATF & filter. I took a sample with a JG Lubricant Services used oil analysis kit. They use Polaris Laboratories. Sent it in and 5 working days later here are the results. This is the same fluid and filter as before (see result #1).

Lab flagged the viscosity of 5.6, so I called Tom Johnson of JG Lubricant Services. Tom is co-owner of JG Lub. He spent 30 yrs with GM/Allison as a fluids engineer. He said when viscosity gets to 5.5 they recommend changing the fluid. When viscosity gets to 5.0 bushings etc start to wear. So my timing this fluid/filter change worked out good. Not too early, not too late.

Tranny has 174k miles since new. 43k miles ago, while doing the engine rear main seal job, I replaced the original torque converter as a preventative mx item. That was the last time I changed all the fluid and the filter. View attachment 369690

Good ”in-the-field” info! Thanks.

 

[donjetman]

The vehicle doesn't ever see any severe duty service. No towing. Mostly rural and hwy driving. No stop n go. I drive the speed limit and never hot rod it.

43k miles ago, pretty much "ALL" the atf got changed (11 qts) because I not only dropped the pan, I changed the torque converter too which holds 5 qts.

This time I only changed the 6 qts that comes out when the pan is removed.

I'm planning my next change for about 25K miles from now, which is at 200k miles on the odometer.

 

[jmil1974]

Fluid changes and cleaning (TB, intake, top end) are the most important maintenance items on cars now...if you want it to last. Well done.

 

[thingraylinetah]

Very informative.

 

[j91z28d1]

interesting.. do you know what the viscosity of new dexton 6 is?

I just got some results back a few weeks ago, different lab(black stone) and different gm tranny(2ML70). first one of its type they had tested. so nothing really to compare to but looking at it, viscosity is shown at 100c being 5.55. only 9k since I changed the fluid and filters, all 12qt comes out with these trannys. (no tq converter) but I just got back from my first long tow with this vehicle. 2k miles towing a car, I'd guess 6k lbs. since I was sending the car's sample out after a track day, I sent some of the trucks atf too. they didn't mention anything about viscosity looking low, but if 5.5 is considered low for a 6L80, seems like it would be low for just about all autos.

which left me wondering what fresh fluid would test at, since mine is only 9k old and my tranny Temps never budged over 167deg the whole trip. so it really shouldn't have beat up its fluid, but also fluid change is way cheaper than a rebuild haha. worth erroring on the side of to often. especially with an odd ball tranny that might be difficult to find a rebuilder.

 

[donjetman]

interesting.. do you know what the viscosity of new dexton 6 is?

I just got some results back a few weeks ago, different lab(black stone) and different gm tranny(2ML70). first one of its type they had tested. so nothing really to compare to but looking at it, viscosity is shown at 100c being 5.55. only 9k since I changed the fluid and filters, all 12qt comes out with these trannys. (no tq converter) but I just got back from my first long tow with this vehicle. 2k miles towing a car, I'd guess 6k lbs. since I was sending the car's sample out after a track day, I sent some of the trucks atf too. they didn't mention anything about viscosity looking low, but if 5.5 is considered low for a 6L80, seems like it would be low for just about all autos.

which left me wondering what fresh fluid would test at, since mine is only 9k old and my tranny Temps never budged over 167deg the whole trip. so it really shouldn't have beat up its fluid, but also fluid change is way cheaper than a rebuild haha. worth erroring on the side of to often. especially with an odd ball tranny that might be difficult to find a rebuilder.

Depending on the brand, Dexron VI starts life (virgin) at a viscosity of 5.8 to 6.3. If it were mine I would drain/condemn the atf at 5.4 and below. By 5.0 bad things start to happen according to Tom Jonson of JG Lubricant Services. He owns JGLS, is an x-GM fluid engineer, and I use their used oil/atf analysis kits for all of my used "ATF" analysis on all my vehicles, mainly because he is available on the ph to discuss the results if I have questions. They use Polaris Labs just like Oil Analyzers Inc/Amsoil.
Valvoline Dexron6 specs
Mobil Dexron6 specs
Amsoil ATL

 

[j91z28d1]

amsoil would seem to be a nice upgrade from ACDELCO dexron 6. interesting.

what did you start with? I normally use mobile 1 stuff, but since this is a tranny I don't fully understand or have a lot of other people to ask about, I just used the oem stuff. I'm sure there's more to it than just good viscosity thou. very interesting.

here's my report.

 

[donjetman]

@j91z28d1
Amsoil ATL would be good. I've used it a lot over the yrs. Good stuff. I have 30+ qts on the shelf here. I bought it for a great price from an Amsoil dealer that was moving out of state and didn't want to haul it. I have plenty of Dexron6 too.

I started (Oct of 2018) with a VERY used 130K mile 07 Yukon Denali that we bought off a used car lot with who know what for mx history.

I immediately concluded it needed an engine rear main seal. So out comes the transfer case, tranny and torque converter to get to the rear main seal.

While The tranny was out I changed its fluid, filter, torque converter. and a couple of other seals & o-rings while I was in there. All new ACDelco Dexron6 went back in, 11-12 qts.

2+ yrs and 26k miles later I did a used atf analysis. I left the fluid and filter in place. Then 2+ more yrs and 17k more miles (43k miles total on fluid and filter) I did another analysis. I decided to change both fluid and filter, 6 qts). ACDelco Dexron6 went back in. My tranny mx schedule now is to change whatever I can get out of the pan (5-6 qts) every 25k miles, then at 50k change the filter too.

Here a thread I did in 2018 with a lot of pics of taking tranny out, xfer case, changing atf, etc etc:
https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/page-3

 

[donjetman]

@NickTransmissions
Below is my latest (3rd) used ATF analysis report for the 6L80 in our 194k mile 07 Denali.
First 2 reports are in post #1.
I took this sample sooner than planned because I got some tranny codes last Nov/Dec. So I dropped the pan and installed new TECHM pressure switch membranes:
https://www.tahoeyukonforum.com/thr...p0842-p0872-p0877-update.145047/#post-1838411
Looks good to me. Next scheduled mx will be at 225k miles, which should consist of dumping the 6 qts in the pan and replenishing with fresh Dexron6.

Torque converter was replaced 5+ yrs ago at 130k miles.

 

[NickTransmissions]

@NickTransmissions
Below is my latest (3rd) used ATF analysis report for the 6L80 in our 194k mile 07 Denali.
First 2 reports are in post #1.
I took this sample sooner than planned because I got some tranny codes last Nov/Dec. So I dropped the pan and installed new TECHM pressure switch membranes:
https://www.tahoeyukonforum.com/thr...p0842-p0872-p0877-update.145047/#post-1838411
Looks good to me. Next scheduled mx will be at 225k miles, which should consist of dumping the 6 qts in the pan and replenishing with fresh Dexron6.

Torque converter was replaces 5+ yrs ago at 130k miles.
View attachment 420284

Looks good, man!

 

[j91z28d1]

Looks good, man!

little off topic, but any thoughts on a full tranny fluid flush vs dropping the pan and getting 4qt out? Just curious.

 

[15burban]

Great info! Thanks for sharing @donjetman

little off topic, but any thoughts on a full tranny fluid flush vs dropping the pan and getting 4qt out? Just curious.

We just got our suburban a few months ago but I plan on doing exactly the same as my other truck which is a drain and refill every year and a new filter every 3-5 years depending on mileage.

 

[blackelky]

little off topic, but any thoughts on a full tranny fluid flush vs dropping the pan and getting 4qt out? Just curious.

I got 6-7 quarts when I changed my filter for a 6l80e

 

[NickTransmissions]

little off topic, but any thoughts on a full tranny fluid flush vs dropping the pan and getting 4qt out? Just curious.

I just drain the pan on my Tahoe every 30k, fluid is always red and smells like new (60k on its most recent rebuild, did fluid and filter). You can do the full flush instead; either is fine.

 

[j91z28d1]

I just drain the pan on my Tahoe every 30k, fluid is always red and smells like new (60k on its most recent rebuild, did fluid and filter). You can do the full flush instead; either is fine.

every 30k is a interesting interval. might be the shortest I've seen anyone talk about. makes sense thou since you aren't getting it all out, just change it a little more often.

 

[NickTransmissions]

every 30k is a interesting interval. might be the shortest I've seen anyone talk about. makes sense thou since you aren't getting it all out, just change it a little more often.

That and Vegas gets well over 100 degrees from Jun-Sep so we have shorter intervals for servicing than non-Desert climates. Plus i dont use Dex6, which if you do then intervals are longer...think that also applies to the latest formulations as well but dont quote me on it.