[Leucosticte]

Recently I did a fluid and filter change on my GM tranny, after this service the transmission has started to shift much better and smoother overall. However, there is still an infrequent delay when it shifts gears, mostly when it's shifting up after I let off of the gas after acceleration. I heard that the mechatronic seals often cause this issue on the ZF autos so I wanted to see if this would solve the issue for the GM as well as they are different designs.

Here are the parts that I've found so far:

Sealing Sleeve with O-Rings for Auto Trans Valve Body,
Part #: 24-15-7-572-607-M9


Seal Set - Valve Body to Pump,
Part #: 24-27-7-581-598-BO

I've read on a Singapore BMW forum that changing the transmission speed sensor also helps, with the following part number:

Speed Sensor for Automatic Trans GA6L45R,
Part #: 24-35-7-646-994-BOE


My question is has anyone on this forum that has done this maintenance on the GM transmission? Was there any noticeable improvement in shifting? Is there a possibility that my transmission is simply worn and on its way out which causes this delay sometimes?

[CTinline-six]

How many miles on the trans?

While refreshing the seals certainly won't hurt anything, the GM transmission is known for having "so-so" programming. In fact I would say it is probably the only downfall with my car. After a fluid change it will definitely be smoother, but smooth certainly isn't how I would describe it. Mine does similar to what you describe even when I bought it at 32k miles.

For what it's worth, I used Valvoline MaxLife ATF which seemed to improve it even 20k miles later.

[Leucosticte]

Originally Posted by CTinline-six

How many miles on the trans?

While refreshing the seals certainly won't hurt anything, the GM transmission is known for having "so-so" programming. In fact I would say it is probably the only downfall with my car. After a fluid change it will definitely be smoother, but smooth certainly isn't how I would describe it. Mine does similar to what you describe even when I bought it at 32k miles.

For what it's worth, I used Valvoline MaxLife ATF which seemed to improve it even 20k miles later.

135k miles, did the fluid change at 134k, used BMW Dexron VI.