Photos GM transmission DIY Flushing

[crashz]

GH,

Maybe the old fluid was worn to point of thinning the viscosity (the torque converter is a natural fluid shear) and the new batch of fluid also being Dextron VI is more resistant to shear forces? Unless you feel the engine stutter and stall, I wouldn't worry to much. At 650 rpm, it sounds normal. Stalling would indicate a faulty converter clutch issue.

The Sea-Foam would also thin the fluid. So maybe you are seeing a cumulative effect.

 

[Gale Hawkins]

The goal was to push out the new oil on each start up until it starts coming out of the exit point of the ATF cooler to insure the TC now has new ATF. Only old ATF with be that trapped in the valve body.

Ford in a test I was told by one involved with the lab testing found after a bucket flush the TC contained 97% new ATF. We like to use one gallon more than total amount of ATF required for a 'new' fill.

Any thoughts on why after the Sea Foam use and bucket flush more braking is required to hold it at a stop light nowt?

 

[Gale Hawkins]

GH,

Maybe the old fluid was worn to point of thinning the viscosity (the torque converter is a natural fluid shear) and the new batch of fluid also being Dextron VI is more resistant to shear forces? Unless you feel the engine stutter and stall, I wouldn't worry to much. At 650 rpm, it sounds normal. Stalling would indicate a faulty converter clutch issue.

The Sea-Foam would also thin the fluid. So maybe you are seeing a cumulative effect.

Thanks. That makes sense. While I expect the Sea Foam put more stuff in solution that then got pumped out in the bucket flush less transmission slipping now at the stop light may be all or mainly due to the new ATF friction modifiers. If the Sea Foam did as it claims and removed some varnish from the bands that would have helped but there to know that for sure without a before and after use tear down.

The transmission performed flawless on the 357 mile trip yesterday so I am happy about that and it is filled with very pink Dexron VI.:thumbsup:

 

[Car Doc]

The first place main line pressure goes after the pump is the pressure regulator and at that point the fluid is diverted into lube circuits and other valves etc.

A certain percentage goes straight into the cooler right at the pressure regulator so as soon as the pump starts moving fluid it will be pumping the new oil right into the cooler it has to circulate awhile before draining it if you want to have a proper dilution imho.

 

[crazyal]

My girlfriend had a 04 Trailblazer that had about 60k on it. The fluid had gotten so bad that it would no longer shift. One day while plowing I left it idling in neutral for a few minutes to let the exhaust warm up. When I put it into reverse it would just rev. The fluid was a brown sludge. Cost over $200 to have the local garage to flush it (being winter and not having a garage I wasn't going to do it myself).

Since then I have gotten rid of the Chevy and built a garage. I never understood why GM couldn't build a transmission that didn't need the fluids flushed. My Tundra has over 140k on it now and the fluid looks like new. I've used it to tow 1000s of miles pulling loads at it's upper limits.

I did find a place selling different clutch plates that solved the problem, I sold the TB before having to rebuild the tranny so I don't know if it was BS or true.

 

[Gale Hawkins]

The first place main line pressure goes after the pump is the pressure regulator and at that point the fluid is diverted into lube circuits and other valves etc.

A certain percentage goes straight into the cooler right at the pressure regulator so as soon as the pump starts moving fluid it will be pumping the new oil right into the cooler it has to circulate awhile before draining it if you want to have a proper dilution imho.

With the GM 4L60 and 4L80 that I have done the buck flush the brown stuff came out first then started going to clean pink in color. I understood the ATF pasted through the torque converter before going to the cooler.

The Honda bucket flush done on You Tube worked the same way. I can understand some ATF is going in many directions at the same time but it can not be much based on the color of what comes out of the cooler during a bucket flush.

I agree there can be some back flushing when the engine is shut off each and every time or the ATF level would be the same when the engine is off or running.

 

[Car Doc]

Hey Gale,

I am not trying to be argumentative so you know that ok all I am doing is pointing out something I am well familiar with hoping to help is all? :thumbsup:

The converter will drain only half way down after an overnight sit if you are lucky, the lube oil does go into the converter but it isn't at line pressure. I don't have the exact percentage of how much oil it is but a circulation is all that's necessary for the converter to work there is more to it but to say the oil goes there first isn't 100% true the cooler is first and the converter is lube oil fed from the regulator, and the converter clutch is another circuit and is regulated pressure thru the clutch solenoid a completely different circuit btw.

I have studied fluid charts until I am blue in the face and cross eyed repairing tranys that is how you fix things is by fully understanding them.

My suggestion is for future trany flushes that if you were to simply run the car a few minutes between pumping the pan dry you would greatly increase the dilution which is imho the whole reason to take a short cut like this in the first place to get as much old oil out as possible.

I applaud the fact you are doing something most tranys never get serviced hence the recent worldwide trend of the removal of dipsticks and the manufacturers belief that trany oil is a lifetime fill now. (not)

The "experts" on boobtube are not impressing anyone that actually works on cars or anything else for that matter its viewer beware from my point of view.

 

[Gale Hawkins]

I hear you on the You Tube techs.

A person that said Ford had actually tested the change out of the TC fluid using the bucket flush when he worked for Ford said after the flush Ford techs checked and found the fluid to be 97% new.

The reason I do not shift between pump downs is to only push new fluid forward (not a mix of old/new). If your way works for you that is good but my goal is to get as close to 100% change out of ATF.

I have added a can of Sea Foam to the Blazer transmission and if I can get a couple hundred miles on it by the weekend we will do the bucket flush on it while everything is still setting out from ding the Escalade last weekend. I will try to pay close attention to how much it takes for it to start looking new. Thanks

 

[Gale Hawkins]

I used Patrick's bucket flush write up posted above to do the Blazer this weekend and other than finding the connection VERY hard to separate it worked as described.

As with the Escalade I added a pint of Sea Foam to the transmission a few days before but I only drove the Blazer 120 miles instead of 200 that I did on the Escalade. When we poured the 5 gallon bucket into the gallon containers there were some fine solids in the very bottom of the bucket that we pumped into.

The output had less pressure when pumping down the Blazer than the Escalade. I am not sure why unless the Blazer has some ATF cooler restriction. It was a forceful stream but not like the Escalade. The transmission before this Jasper was eaten alive and I have wondered if maybe it loaded the cooler with junk that did not get flushed well by the shop

 

[orezok]

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).