2024 10-Speed Transmission Service

ssgballistics · August 24

Has anyone serviced the transmission in their 24’ gasser? I’m going to be dropping the pan and replacing the filter and fluid in the next couple of weeks. I am under the impression the service should be very similar to that of Duramax trucks. Do you have to drop the exhaust to remove the pan? How much fluid does it take (I ordered 10 qts)? I would appreciate any information from someone who has done this.

bruceb58 · August 31

I haven't done it yet but I do know you need to drop the exhaust according to the service manual.

When I drop my pan, I will be putting in an after market pan that has a drain plug.

64BAwagon · August 31

I think you may be able to sneak the pan out without dropping the exhaust. It may need some prying to get it cleared or loosening of the trans mounts and prying up. I consider this an epic fail and a sure sign that Allison didnt have a huge role in this design since they have a history of building transmissions that are service friendly.

Mines good for now but I already have a Superior products drain plug setup thats going on it when I do.

I dont have an exact count on the qts needed but I would buy a few extra just in case.

When refilling the trans I will use the M18 nipple that I bought with the hose and run that up to the normal dipstick area rather than pumping into the side of the case. I believe I posted about the setup before. SInce I know mine is at the correct fill I will just measure the amount I drain and replace that accounting for the inevitable spillage.

Just for grins, I got back from a trip towing my 12,500# fifth wheel in 85 degree temps and my trans never went over 176 degrees with a mic of freeway and stop and go city in the 200 miles.

lineman1234 · August 31

Maybe its a simple regular cab thing........... But...........

I just looked under my 2024 regular cab, 6.6 gasser, 3500 4x4. The transmission drain plug is in the front drivers side of the pan. It wont drain all of it as there is a drop down part. Then the pan can removed very easy without doing anything with the exhaust. Yes, it has to be slid forward of the exhaust then it will come right out, and go back in.

Ill will attempt, to do some fluid sucking to get the rest out of the deeper part of the pan to help with less sloshing.

For the others/normal people with a 4 door. Maybe someone could confirm or post that the exhaust needs to be dropped or not.

lineman1234 · August 31

(( 64BAwagon )) You posted right before i hit submit. Did you confirm by looking under for the 4 door people? or i can look when my friend gets back from camping next week and add to the 4 door being like my 2 door or it being a pain. He has a gmc 4 door.

lineman1234 · August 31

Has anyone looked into if the transmission pan has a reusable gasket or is it like my past 2015 ram diesel with a pan that had, no, drain plug and the pan gasket was not reusable.

Capt Bob · September 1

2 hours ago, lineman1234 said:

Maybe its a simple regular cab thing........... But...........

I just looked under my 2024 regular cab, 6.6 gasser, 3500 4x4. The transmission drain plug is in the front drivers side of the pan.

I may be mistaken but I believe that plug is used to check the level of fluid in the tranny. The correct level is obtained (while at operating temp) when fluid is reduced to a slow drain. It is not to be confused as an actual drain plug for emptying the pan.

johnnyquick · September 1

8 hours ago, bruceb58 said:

I haven't done it yet but I do know you need to drop the exhaust according to the service manual.

When I drop my pan, I will be putting in an after market pan that has a drain plug.

what pan are you looking at?

newdude · September 1

On 8/24/2024 at 5:26 PM, ssgballistics said:

Has anyone serviced the transmission in their 24’ gasser? I’m going to be dropping the pan and replacing the filter and fluid in the next couple of weeks. I am under the impression the service should be very similar to that of Duramax trucks. Do you have to drop the exhaust to remove the pan? How much fluid does it take (I ordered 10 qts)? I would appreciate any information from someone who has done this.

Pan drop takes just over 14 quarts. Dexron ULV fluid, p/n 19352619.

6 hours ago, lineman1234 said:

Maybe its a simple regular cab thing........... But...........

I just looked under my 2024 regular cab, 6.6 gasser, 3500 4x4. The transmission drain plug is in the front drivers side of the pan. It wont drain all of it as there is a drop down part. Then the pan can removed very easy without doing anything with the exhaust. Yes, it has to be slid forward of the exhaust then it will come right out, and go back in.

Ill will attempt, to do some fluid sucking to get the rest out of the deeper part of the pan to help with less sloshing.

For the others/normal people with a 4 door. Maybe someone could confirm or post that the exhaust needs to be dropped or not.

That is not "technically" a drain plug. That is the fluid level check plug for checking the level.

5 hours ago, lineman1234 said:

Has anyone looked into if the transmission pan has a reusable gasket or is it like my past 2015 ram diesel with a pan that had, no, drain plug and the pan gasket was not reusable.

Should be, most all the ones GM uses are these days.

64BAwagon · September 1

What he said

lineman1234 · September 1

I like to learn things.......

And i thought it was a drain plug.

newdude · September 1

2 hours ago, lineman1234 said:

I like to learn things.......

And i thought it was a drain plug.

I mean...yes you "can" drain a fair amount out of there but obviously you won't empty the pan. There's a stem pipe that it screws into, it will drain fluid to a point at or just below the stem pipe, so the pan itself will still be pretty fluid loaded.

ssgballistics · September 1

I appreciate everyone’s feedback. I ordered additional DEXRON ULV for the job. I’ll try to come back here with a detailed post of my experience. I’m sure someone else will be looking for this info in the future.