Changed my filter and fluid on 8l90 8 speed today

[tommyboy180]

Are there any others on this forum that have done the 8l90 fluid change themselves? Interested to see what their pan/ magnets look like.

Just did my 8L90 today. Didn't take pics of the pan but it looked identical to your pictures. The magnets were almost exactly looking like yours, the fluid almost the same exact color (a little darker on mine). When I wiped out the pan I was getting dark covered rags.

Seemed like a normal trans fluid change to me. I've done plenty.

it took me longer than 4hrs to do. Sucking the fluid out took forever using my brake fluid vacuum. Dropping the pan required me to pull down on the exhaust (that pissed me off, what a terrible place GM engineers!). Swapping the filter had me confused for a second because I thought the back plastic peg was supposed to go into a hole and not the slot. Filling took a long time since I have a manual pump.

I put 8.5qts in, brought it up to temp and let it drain until it was a non-consistent drip. So prob around 8qts swap. Would have a ton faster if I had a drain plug from the factory on the pan.

 

[SuperOldSchool]

Nice job!! How many miles since last changed?

 

[GRAYGEORGE]

OP - Brought truck to the dealer for a few last warranty items (before it ran out) and they did the trans temp sensor replacement. So that’s another ~8qts fresh fluid.

It shifts pretty nicely now, though still get some random clunks for whatever reason.

What was the part # for the temperature sensor on your 8L90?

 

[tommyboy180]

Nice job!! How many miles since last changed?

I bought it at 70K miles, looking at the service history of the truck I think it's the first time it was done.

 

[SuperOldSchool]

What was the part # for the temperature sensor on your 8L90?

I believe

24298757​

 

[GRAYGEORGE]

Thanks

 

[SuperOldSchool]

OP again. Changed again today (fluid and filter) at 130k…. 31k on the fluid. It was still pretty red and not much paste on the magnets.

Also, added the SureCool thermostat to lower trans temps. Good stuff!

 

[RobH]

Just did my 8L90 today. Didn't take pics of the pan but it looked identical to your pictures. The magnets were almost exactly looking like yours, the fluid almost the same exact color (a little darker on mine). When I wiped out the pan I was getting dark covered rags.

Seemed like a normal trans fluid change to me. I've done plenty.

it took me longer than 4hrs to do. Sucking the fluid out took forever using my brake fluid vacuum. Dropping the pan required me to pull down on the exhaust (that pissed me off, what a terrible place GM engineers!). Swapping the filter had me confused for a second because I thought the back plastic peg was supposed to go into a hole and not the slot. Filling took a long time since I have a manual pump.

I put 8.5qts in, brought it up to temp and let it drain until it was a non-consistent drip. So prob around 8qts swap. Would have a ton faster if I had a drain plug from the factory on the pan.

Did you install a drain plug in your pan? I've used drain plugs from Summit in the past.

 

[tommyboy180]

Did you install a drain plug in your pan? I've used drain plugs from Summit in the past.

No. Thought about it several times but the risk of a leak versus how often you swap trans fluid didn't seem like a good traide. Based on milage you're prob doing this job every 3 years so the 4hr job doesn't seem that bad. Good luck!

 

[tom3]

You guys reuse the OE gasket or replace?