Transmission oil change at 115,000 miles

03envoy

Original poster
Member
Dec 25, 2011
537
Hello,
I am looking to change all of my fluids but I am really worried about this one, every car that my Dad has changed the trans oil on has slipped after. Could this be caused by a transmission flush? Some people say don't change it after 100,000 , but I tow alot and worry about thin oil possibly getting to hot. Any recommendations would be awesome, Thanks,
Trent
 

gmcman

Member
Dec 12, 2011
4,656
What were the intervals that your dad changed the fluid at?

What do you tow regularly and what is the weight? Do you have an aftermarket cooler installed? 110K is alot on stock fluid.
 

Mark20

Member
Dec 6, 2011
1,630
There is a lot of bad feelings about a power flush pushing fluid backwards through the system. Gm's recommendation is to just drop the pan and refill. I've towed a very heavy camper with the Envoy without an external cooler (yeah yeah I'm stupid) and when the weather warms up I'd like to do a full flush on the tranny by disconnecting one of the lines to the cooler in the radiator. I have done the drain and fill done at about 55K and am at 70k now.
 

Iahawkeye

Member
Jan 24, 2012
52
03envoy said:
Hello,
I am looking to change all of my fluids but I am really worried about this one, every car that my Dad has changed the trans oil on has slipped after. Could this be caused by a transmission flush? Some people say don't change it after 100,000 , but I tow alot and worry about thin oil possibly getting to hot. Any recommendations would be awesome, Thanks,
Trent

I have been told that if you wait too long to change the oil, you might be better off to not change the oil at all. That said, i imagine that if you were to change the fluid a little at a time and slowly introduce more viscous fluid to the system you might be alright. I think that a sudden shock of all new oil would be hard on seals, but if you drop the pan and just change that oil and then down the road, change it again, you should be alright. Most of the transmission oil is left in the torque converter so you only change about a 1/3 of the oil by dropping the pan method. However, i am by no means an expert. Good luck.
 

mnypitTBEXT

Member
Jan 29, 2012
133
Many shops will not even do a trans fluid change after about 75k if its never been done before. Transmission fluid has detergants in it and when you replace it at that high a mileage you take a chance of the varnish on the parts being cleaned off with the new fluid and it may start slipping. At 115k, I would just start putting cash away for another transmission.
 

Wyle

Member
Dec 4, 2011
200
Owner's Manual says change fluid and filter every 50k miles for severe conditions and 100k for normal conditions. I was a slacker and didn't change it until about 122k miles. 5 qts of Valvoline Dex VI and a new filter after dropping the pan. No problems for 3500 miles. I don't tow anything, but AZ summers and mountain trips aren't considered "normal" conditions per the manual. I figure I'll start changing it on 50-60k intervals from now on.
 

03envoy

Original poster
Member
Dec 25, 2011
537
My dad didnt own the vechical before me, that's why I am going to figure out if the lady changed it regularly and if she did I am going to change it. And the method of doing a lol bit at a time is a good one! Lol
Thanks!
Trent
 

03envoy

Original poster
Member
Dec 25, 2011
537
gmcman said:
What were the intervals that your dad changed the fluid at?

What do you tow regularly and what is the weight? Do you have an aftermarket cooler installed? 110K is alot on stock fluid.


My dad didn't own vechical before me, I and going to find out what the intervals were. I usually tow two sled up north, probably 1200 lbs. And no, no cooler.
 

deepblue

Member
Dec 5, 2011
56
Just an observation... seems a lot of folks are "religious" about engine oil changes but then choose to ignore the transmission oil/filter. It is only slightly more difficult than an engine oil change, more messy than difficult. It's very cheap insurance. A new filter, clean pan and fresh fluid.. Priceless !! I'll do mine every 25k and never look back. Just my 2 cents.
 

davenay67

Member
Jan 16, 2012
217
So much confusion and so many old wives tales continue to circulate concerning changing of ATF.

I know some certified transmission techs from other forums I hang out on, and they say that better late than never when it comes to changing the ATF. They also recommend the pan drop, filter replacement and ATF refill method rather than flushing. Then keep changing on a regualr basis after that.

What does the ATF currently look like in your tranny. You can get an idea by pulling the dipstick and checking the color and smell of the ATF. A red-ish color is a good sign, a dirty color or nasty smelling not so good.

I've mention in other posts on the old site that the TB is new to me (my wife owned it before we met) and I suspect it has been slightly neglected in the past. I plan on changing the ATF this very weekend with the pan drop method, currently 127K on the odo. I have no qualms about doing this and I will gladly be your guinea pig..!! :biggrin:
 

navigator

Member
Dec 3, 2011
504
My TB sees mostly highway travel with some towing of a small bass boat and a little offroading.
I didn't change mine until about 90k, my fluid still "looked" really good, there was only light collection on the magnet.
I just did a pan drop and new filter.
I think at 25k I'll drop and change it again and put one of those drain plugs in the pan and just change the fluid every 25k miles and the filter every 50 k. Adding the drain should take a lot of the pain out of it.
I want to say a drop and drain takes about 5-6 qts and full flush is about 12.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Last summer at about 125K I did mine for the first time. I just dropped pan and changed filter, then added the 5 or 6 qts to top it off. Have had no negative issues since. Actually did seem to help, but I added a trans cooler when I did it. I plan to drop the pan and swap another fresh 5 or 6 quarts in this summer as well.
 

DJones

Member
Jan 21, 2012
701
St. Petersburg, Florida
HARDTRAILZ said:
Last summer at about 125K I did mine for the first time. I just dropped pan and changed filter, then added the 5 or 6 qts to top it off. Have had no negative issues since. Actually did seem to help, but I added a trans cooler when I did it. I plan to drop the pan and swap another fresh 5 or 6 quarts in this summer as well.

I have the same story here too, but mine is 3 years older and I didn't install a cooler. Look at my signature for how many miles I have driven since.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Fluid is red. It's time for a change, I think it must have been changed then right? I am going to drop the pan and put new fluid in when I do the oil change. Sounds good right? Thanks for all the replies!!!
 

rmsg0040

Member
Dec 10, 2011
285
Should look at the dorman pan if you want to change the oil frequently, comes with a drain plug and has been used by members with success.

Part number 265-811
 

TB360

Member
Dec 29, 2011
169
I'm almost 115K. Never changed it and will wait until it dies. We have the Tahoe too and it's at 170K without any flushing done. It's either do it on time or never when you missed it. Tranny for TB doesn't cost as much as european cars anyway. I do not encourage everyone to do what I did, if you done it on time, that's fine, I'm just saying if you missed the scheduled maintenance, then just leave it alone.
 

vipergg

Member
Dec 7, 2011
191
deepblue said:
Just an observation... seems a lot of folks are "religious" about engine oil changes but then choose to ignore the transmission oil/filter. It is only slightly more difficult than an engine oil change, more messy than difficult. It's very cheap insurance. A new filter, clean pan and fresh fluid.. Priceless !! I'll do mine every 25k and never look back. Just my 2 cents.


Come on up to Rochester and i'll hire you to do mine !!! :thumbsup:
 

Sparky

Member
Dec 4, 2011
12,927
FWIW, my Trailblazer had 112k on it when I got it and the fluid looked pretty old (much more brown than red, probably original fluid from the looks of it). I pumped out all the old fluid using the directions from the OS (disconnected the one line from the trans cooler, attached a hose, and started the vehicle so the gyrator pump in the trans pumped all the fluid out of it). Filled with nice fresh fluid after pulling the pan, changing the filter, and installing a transgo SK-4L60E kit (preventative for a TCC valve issue the 4L60E is known for). I'm at nearly 154k miles now, never even a slight hiccup. It worked fine before the change BTW.

My brother had a beater 95 Ford Taurus last summer that had never had the fluid changed (or at least it was a very, very long time ago) and the fluid looked like muddy water. Trans started slipping badly too. Had it completely flushed and a new filter installed, and even now that transmission shifts perfectly fine.

I'm of the opinion that if a fluid change "causes" your trans to die, the trans was just about dead already.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Sparky said:
FWIW, my Trailblazer had 112k on it when I got it and the fluid looked pretty old (much more brown than red, probably original fluid from the looks of it). I pumped out all the old fluid using the directions from the OS (disconnected the one line from the trans cooler, attached a hose, and started the vehicle so the gyrator pump in the trans pumped all the fluid out of it). Filled with nice fresh fluid after pulling the pan, changing the filter, and installing a transgo SK-4L60E kit (preventative for a TCC valve issue the 4L60E is known for). I'm at nearly 154k miles now, never even a slight hiccup. It worked fine before the change BTW.

My brother had a beater 95 Ford Taurus last summer that had never had the fluid changed (or at least it was a very, very long time ago) and the fluid looked like muddy water. Trans started slipping badly too. Had it completely flushed and a new filter installed, and even now that transmission shifts perfectly fine.

I'm of the opinion that if a fluid change "causes" your trans to die, the trans was just about dead already.

Thanks, Do you think this kit will work just fine? I am not goin to flush, Just drop the pan clean, Replace gasket, and fluid.

Buy Pro-King Automatic Transmission Filter Kit FK-373 at Advance Auto Parts
 

Sparky

Member
Dec 4, 2011
12,927
03envoy said:
Thanks, Do you think this kit will work just fine? I am not goin to flush, Just drop the pan clean, Replace gasket, and fluid.

Buy Pro-King Automatic Transmission Filter Kit FK-373 at Advance Auto Parts

Check your trans pan. Is it flat or does it have a step in it? If it has a step (like 95% of the trailblazers out there) then you need the deep pan filter. I'm not sure if that one you linked to is for the deep pan or not.

Also, if you just drop the pan only, you'll only get 1/2 the trans fluid changed, at most. So if you do it that way, make sure to do another pan drop and change well before another 100k. If I were doing a pan drop only I'd check it in 20k miles for color - if it is dark, change it, if it still looks good, check it again in 10k.

I'm coming up on 40k since my fluid change (it was a complete change, not partial), so I'm going to be checking its color soon. Last I checked it, it still looked great, so I figure at 40k it should still have a lot of life left in it.


One thing I thought about after re-reading your OP was about your dad having trans slip after a flush. Some shops "flush" by pumping fluid backwards through the system and never even drop the pan to change the filter. This has the side effect of knocking any gunk off the filter but not getting it totally out of the system, and now having a well-used filter still in there. Those back flushes can be what causes issues. A flush that is purely a total fluid empty and a new filter shouldn't cause a trans to fail. Forcing all that garbage backwards through the system can certainly make it fail.
 

03envoy

Original poster
Member
Dec 25, 2011
537
Sparky said:
Check your trans pan. Is it flat or does it have a step in it? If it has a step (like 95% of the trailblazers out there) then you need the deep pan filter. I'm not sure if that one you linked to is for the deep pan or not.

Also, if you just drop the pan only, you'll only get 1/2 the trans fluid changed, at most. So if you do it that way, make sure to do another pan drop and change well before another 100k. If I were doing a pan drop only I'd check it in 20k miles for color - if it is dark, change it, if it still looks good, check it again in 10k.

I'm coming up on 40k since my fluid change (it was a complete change, not partial), so I'm going to be checking its color soon. Last I checked it, it still looked great, so I figure at 40k it should still have a lot of life left in it.


One thing I thought about after re-reading your OP was about your dad having trans slip after a flush. Some shops "flush" by pumping fluid backwards through the system and never even drop the pan to change the filter. This has the side effect of knocking any gunk off the filter but not getting it totally out of the system, and now having a well-used filter still in there. Those back flushes can be what causes issues. A flush that is purely a total fluid empty and a new filter shouldn't cause a trans to fail. Forcing all that garbage backwards through the system can certainly make it fail.



Yep, Trans figured out what it was. Crappy trans shops. I am going to drain out all the fluid and drop the pan. But, Not flush. Yes, That kit is for the deep pan. Thanks Sparky! My fluid is red rightnow so its not bad. Which means they did change it at some point.:yes:
 

suburbs

Member
Jan 6, 2012
86
Purchased at right around 108k, pretty confident the previous owner never did the transmission fluid. Had a full change done at 110k. 3 years and 18k later, no issues.
 

Sparky

Member
Dec 4, 2011
12,927
suburbs said:
Purchased at right around 108k, pretty confident the previous owner never did the transmission fluid. Had a full change done at 110k. 3 years and 18k later, no issues.

Wish I could say that. 42k in 1 year 4 months :crazy:
 

davenay67

Member
Jan 16, 2012
217
03envoy said:
My fluid is red rightnow so its not bad. Which means they did change it at some point.:yes:

Maybe, maybe not. I went ahead and dropped the pan and drained the fluid this past weekend. I am pretty sure that the fluid has never been changed in it's life, but it still came out quite red in color....very surprised to see that. I did the fluid in my VW before the 100K mark and it came out like used engine oil (common for VW's).

Anyway, I used the same kit as your link shows, seems nice enough and the swap was easy. I used the original filter seal because the fit was still good and tight. Getting the old one out looked like it could be tricky without scratching the aluminum tunnel is located in. I plan on doing the same change (pan drop, nerw filter) every 30K from now on to keep the fluid up to par.
 

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