LMM: Transmission fluid change vs flush

[Mac Daddy]

The last time I had the oil changed in my LMM the tech told me that at 50k miles GM suggests that you flush the transmission fluid. I am kinda nervous about changing fluids without changing the filter. Several questions I have:

1.) Is this necessary at 50k miles?

2.) If yes to question 1 then which method is preferred Flush or Change?

3.) If you drain fluid instead of flush would it be possible to get ALL of the old fluid out of the Torque converter in order to have 100% synthetic in transmission?

Thanks for any help in this matter

 

[kenny]

no, flush will get it all out, and I would do it.

 

[Mike L.]

The last time I had the oil changed in my LMM the tech told me that at 50k miles GM suggests that you flush the transmission fluid. I am kinda nervous about changing fluids without changing the filter. Several questions I have:

1.) Is this necessary at 50k miles?

2.) If yes to question 1 then which method is preferred Flush or Change?

3.) If you drain fluid instead of flush would it be possible to get ALL of the old fluid out of the Torque converter in order to have 100% synthetic in transmission?

Thanks for any help in this matter

It would be a good idea to flush at your mileage. Another alternative is to drain pan by pulling plug and adding 7 qts synthetic fluid and drive it for a couple of hundred miles then do the same thing again. If you realy wanted to be a purist you could do it a third time and be pretty close to full synthetic with a lot less trouble.

 

[Mac Daddy]

It would be a good idea to flush at your mileage. Another alternative is to drain pan by pulling plug and adding 7 qts synthetic fluid and drive it for a couple of hundred miles then do the same thing again. If you realy wanted to be a purist you could do it a third time and be pretty close to full synthetic with a lot less trouble.

Mike, once I have the transmission close to full synthetic how often should the fluid be changed or should it?

 

[Mike L.]

Mike, once I have the transmission close to full synthetic how often should the fluid be changed or should it?

If you change it to a TES 295 rated fluid ( TranSynd, Amsoil ), or any other fluid with that rating, you are good for 100K at normal duty or 50K for extreme duty.

 

[Gilez]

I just purchased a 2500HD LTZ, and the trans fluid looks really clean. It has 60K on it. Is there a way to tell what kind of fluid you have?

 

[lddrew]

what's the best way to flush on any ally? i've heard bad things about a regular flush, but good things about drain and also the Hoot method.
thanks guys