Photos GM transmission DIY Flushing

[Gale Hawkins]

One more thing Gale, it's OK to flush the tranny through the cooler (fluid forward), but in our shop we always backflushed the cooler(s). It's not so bad in the radiator cooler, but the auxiliary cooler tends to collect bits and pieces that did not go forward and can reduce flow. Even with a backflushed aux cooler, we always recommended to the customer to replace the aux cooler after a rebuild. If they did not agree, we then put a filter on the return line at no cost. In the long run it saved US money. On a grenaded tranny, sometimes small pieces would collect in the coolers and then break loose later to cause problems.

Of course we used a pulsing air activated flusher for this purpose (knocks the particles loose).

I totally agree on the need to do a powered back flush of the ATF cooler(s) especially after a major failure of a transmission. As you stated this is really the only way to dislodge any solids pumped into it. The 2003 Escalade has a factory auxiliary cooler (tow package which I did not know they had for 2WD SUV's) but the 2002 Blazer does not.

Did the line filter need replacing after time or was it course enought where only the bigger stuff got trapped. I read more and more new ones only have a metal screen over the pump pickup opening.

I know the small shop did some kind of flushing because he said Jasper required it for the reasons you stated.

 

[Diamondpilot]

We installed a Jasper Tranny in our airport truck we had, a Dodge Dakota. They required we buy a kit for install that included a larger aux cooler that bypassed the Dodge OEM cooler. They stated Dodge under sized the cooler and that was part of the problem with so many of them failing. The only way they would now sell a reman was with the new aftermarket cooler.

Chris

 

[Gale Hawkins]

If I had known four years ago what I now know about transmission cooling and how the lack of it is the main cause of transmission failures I may would have gone with an after market. Short of a temperature gauge one is clueless to heat issues only after the transmission is toast. I was taken back to learn the Escalade had one but it is not a Cadillac of yesteryear.

 

[Car Doc]

Running a tranny too cold is bad also.

Running any vehicle in winter with aux cooler only will cause seal and pump problems eventually and adds extra engine load.

I have always used the aux cooler and the radiator cooler because it heats the oil as well as cools it or keeps it at a reasonable temp year around as long as its in good working order as always ymmv.

 

[Gale Hawkins]

Good point Car Doc. I have read some cold climate vehicles are equipment with a ATF by-pass so it can not reach the cooler(s) until a certain temp is reached. When the Hummer used the 4L80-e transmission I think they used a special rated ATF like in AK, etc.

With the transmission functioning as a heat sink for the 200 degree engine it will warm in time but not for your typical short trip.

 

[FlaDon]

So glad that my Allison has a big cooler on it. Tranny temp was about 160 max this trip north. But the gas mileage sucked. 10 mpg with about 17 K weight. Chevy flushed mine about 15K ago but I don't think they did a good enough job. Turning gray on fluid already.

 

[puckgrinder85]

Seafoam or any other agent really isnt necessary at all. ATF is a highly detergent filled fluid and if flushed when they should be, will be very clean. I wouldnt be adding any chemical cleaners into a transmission, especially this day and age.

 

[Gale Hawkins]

Seafoam or any other agent really isnt necessary at all. ATF is a highly detergent filled fluid and if flushed when they should be, will be very clean. I wouldnt be adding any chemical cleaners into a transmission, especially this day and age.

I agree if they are flushed when they should be ATF should be all that is required. While I think there is little question Sea Foam usage the last 50 miles can help cut stuff loose I am starting to see Sea Foam use prior to a full bucket flush of an under serviced automatic transmission can be a positive.

Yes Sea Foam does good marketing for their products but the fact Sea Foam is being used by some doing machine flushes got my attention at first. Short of a before and after tear down there is no way of knowing if Sea Foam use leaves a transmission cleaner or not.

I have not yet read or experienced any down side to using Sea Foam in a transmission and after its use for many years in transmissions I expect there are not any due to its chemical make up and the fact all but the lube part evaporates from a transmission or crankcase due to the heat.

My personal view at this point is doing a bucket flush every 30K miles/3 years so the ATF never changes to brown in color will be the best use of $$$ spent on automatic transmission upkeep. For a typical GM transmission even using the newer Dexron VI at today's price is ONLY $10 per year when using the above flushing approach.

Who would not spend $10 a year to reduce the risk of spending $2500 for parts/labor to replace a transmission if they really grasped the big picture?

 

[Diamondpilot]

I agree about the 30K thing. I have always changed all my tranny fluids at 30K intervals and have had great success. Only 2 tranny failures were in my Dodge 2500. One at 36,000 and one at 68,000 but it had nothing to do with the fluid, it was just a Dodge.:thumbsup: I also had a transfer case failure on a a 89 S-10 Blazer at around 36,000 miles.

Not to bad for a guy who has owned well over 25 vehicles since 1989 and well over 1/2 of my total miles were towing something.

Chris

 

[Gale Hawkins]

I agree about the 30K thing. I have always changed all my tranny fluids at 30K intervals and have had great success. Only 2 tranny failures were in my Dodge 2500. One at 36,000 and one at 68,000 but it had nothing to do with the fluid, it was just a Dodge.:thumbsup: I also had a transfer case failure on a a 89 S-10 Blazer at around 36,000 miles.

Not to bad for a guy who has owned well over 25 vehicles since 1989 and well over 1/2 of my total miles were towing something.

Chris

Well I have learned the 4L60-e transmissions by GM are not bullet proof without care. I bought the Blazer at 102K miles and replaced the transmission at 107K which had been replaced before so the Jasper I put in was at least #3. After about 55K miles the fluid was brown but did not smell bad.

The 2003 Escalade we just bought with 102K miles per GM's history log got a new transmission (reman Goodwrench would be my guess) at 40K so after 62K miles it was very brown but did not seem bad.

I think these are just too light for a 6,000 pound empty vehicle. The Escalade receiver seems to have NEVER been used. The Blazer had a lot of chrome wear on the hitch ball so it had towed and I expect damaged transmissions.

Now that I understand this I am going to change the ATF at least at 30K miles if not before. ATF is cheap relatively. :B

By the way we had a 1993 Towncar and now a 2000 with no transmission issues and I know the 1993 had a lot of miles with NO service after we purchased it with 93K miles.