Looks kind of like it, but why would it not be more at the bottom of the pan? I don't have an 8 speed in my truck.

 

If it was, it would be on the bottom, not at the top. That should be stand pipe or check plug.

GM 8L90 – The Other 8 Speed Automatic: Part 1 - Transmission Digest

One example of how time flies by is the fact that there has been an eight-speed automatic transmission on the road since 2007.

www.transmissiondigest.com

The push lock fill plug is on the passenger side of the case and the pan is outfitted with a stand pipe. When the correct transmission temperature is achieved (about 100 F), raise the vehicle and remove the stand pipe plug to see whether fluid will trickle out or not. If needed, add fluid through the fill hole until it does.

 

Never mind, it’s just a check plug…. Back to being unhappy about a transmission service

 

I got all the common symptoms of the 8L90. I’m hoping a good flush and filter replacement will improve. Might possibly be 93k with original fluid. Bare minimum 50k of the same fluid. Is there a general conscious on picking the PPE valve bypass or the updated GM thermostat?

 

Does it have the updated new fluid

 

Just in general, replacing the fluid on a failing trans or a trans that has problems will either not help at all or it may make things worse after a few months.

 

The 8L90 specifically has TSBs addressing this though. It’s a common thing that performance issues are actually fixed by replacing the fluid. On first gen 8L90 trucks.

 

If/when you do pull the pan, either put on a new pan that does have a drain plug, or add a drain plug to it.

 

Honestly that system isn’t too terrible to service if you have the correct tools. What I do is just pull the dip stick plug out of the trans, it’s just a rubber plug with a retainer clip, then use a suction tool to remove as much fluid as I can.

Then remove the pan and get the rest of the fluid out of it. Put your pan back up, and then remove your check/fill plug (what you have pictured). Then you can use a variety of tools to fill the pan with fluid. I used a brake pressure bleeder (cleaned out really well obviously). But a standard garden type pump sprayer will work just the same. Fill it until it runs out the check plug hole. Put your check plug and dip stick tube plug back in and fire up the truck and get it to temp. Pull the check plug back out and if some barely dribbles out your good on level. If none comes out, add some more fluid until it starts to come out of the check plug hole.

If the fluid pours out the check plug hole, just let it do so until it all but stops and then your good.

It’s not too terribly much harder than a trans with a drain plug and dip stick, and honestly easier if the truck is on a lift since you don’t need to even lower the truck to fill it back up.

 

Honestly that system isn’t too terrible to service if you have the correct tools. What I do is just pull the dip stick plug out of the trans, it’s just a rubber plug with a retainer clip, then use a suction tool to remove as much fluid as I can.

Then remove the pan and get the rest of the fluid out of it. Put your pan back up, and then remove your check/fill plug (what you have pictured). Then you can use a variety of tools to fill the pan with fluid. I used a brake pressure bleeder (cleaned out really well obviously). But a standard garden type pump sprayer will work just the same. Fill it until it runs out the check plug hole. Put your check plug and dip stick tube plug back in and fire up the truck and get it to temp. Pull the check plug back out and if some barely dribbles out your good on level. If none comes out, add some more fluid until it starts to come out of the check plug hole.

If the fluid pours out the check plug hole, just let it do so until it all but stops and then your good.

It’s not too terribly much harder than a trans with a drain plug and dip stick, and honestly easier if the truck is on a lift since you don’t need to even lower the truck to fill it back up.

Any problems dropping the pan? I’ve seen some videos where people say to drop the exhaust and then I see some videos where people just shimmy the pan around and it comes out pretty easily. While I’m there I might swap out the pan with the PPE pan that has a drain plug. Think the bigger capacity pan will then be a problem getting back on?

 

In my experience it will come out without needing to mess with the exhaust. Very tight fit, but will come out. A deeper pan will very likely not go back on though without lowering exhaust or lifting up the trans.

 

Understood. With more research, I did see a company that takes OEM pans and adds a factory style drain plug to it. I’ll probably do that. BET Performance is the name I believe.

 

Well I decided to purchase a new OEM pan with an OEM style drain plug already installed from BET Performance. There’s an option to buy the pan with or without start/stop. Not knowing if that made a difference or not I still ordered one WITH start/stop since my truck has that. They shipped me the one for WITHOUT start/stop. I’ve compared the two pans in pictures and they have slightly different bump outs in the pan.

Anyone ever have this happen before and know if it really makes a difference or not? I’d assume so because why would GM produce two different molds for the same part for no reason right? I already contacted the seller with no word yet but I wanted to ask here too to confirm if this would be a problem or not.

 

Sounds like they sent you the wrong pan.

 

Well I finally got around to doing everything. Except, I couldn’t do everything. I got the correct pan shipped to me and had a new filter, gasket and of course the updated recommended fluid. Blue label. I absolutely could not drop the pan. I did everything other videos said when trying to wiggle it out.

Something connected to the transmission guts was making the pan not scoot out. I wasn’t about to pry the exhaust or force anything out.
So I had no choice but to just bolt the pan back on and only do a fluid exchange. Sucked out about 6 liters and filled it with nearly 7 so I can just drain out the excess. I don’t see any dripping and no lights. Only time will tell if this helps.

Pretty bummed out I couldn’t use the new pan with a drain plug. On the other hand, the air extractor/dispenser pump worked extremely well. Definitely a good tool to have laying around for when you didn’t know you could use it.

 

After driving around for a few days with the new fluid, I’m absolutely stunned at how much better the transmission is. The shuddering completely went away and no longer has those hard shifts when the fluid gets to higher temps.

I’m goin to drain and fill one more time soon just because I was unable to clean the pan and replace the filter and also I didn’t feel like sucking out the lines. While I’m down there I was also going to do the front and rear differentials along with the 4x4 transfer case.

Question about the front diff and transfer case. Are those gears always moving even when not in 4x4 mode? I almost never use 4x4 unless there’s snow (which there hasn’t been much in the last 50k miles). Just wondering if it makes sense to replace those fluids too. I figured with 95k miles on it and most likely all original fluid, it would be a good idea to replace them anyway just because of age.