Adding ATF to a 10 spd "Allison" branded GM trans in a late model GM truck

[64bawagon]

After determining the plug size on the side of my 2024 Silverado 3500HD "Allison" branded trans I came up with an idea for an easy way to fill the unit after draining and servicing. Rather than pumping ATF into the side plug I figured a better way would be to put a plug into the hole with a hose barb on it and then run a piece of hose up to the firewall area where the dipstick SHOULD be. With a funnel its easy to pour in the fluid needed, pull the hose barb plug and replace it with the stock plug. If you measure the amount of fluid that your drain (assuming you thought the level was correct prior to the service) all you need to do is add the same amount back in and youre done.
This should simplify the service and cut down on the time.
I tried previously to add an AN fitting and a braided line in the same manner except it would be permanent but the placement of the fill hole and the access to it puts the line near one of the Cats and I wasnt confident the line would hold up to the heat so I removed it.
I have a pic of the AN line and also the stock plug for reference.

Scott

 

[AZjeff]

None of the other applications of this 10 spd have a dipstick you could swap in like the easy 6L90 fix?

 

[nascarnation]

After determining the plug size on the side of my 2024 Silverado 3500HD "Allison" branded trans I came up with an idea for an easy way to fill the unit after draining and servicing. Rather than pumping ATF into the side plug I figured a better way would be to put a plug into the hole with a hose barb on it and then run a piece of hose up to the firewall area where the dipstick SHOULD be. With a funnel its easy to pour in the fluid needed, pull the hose barb plug and replace it with the stock plug. If you measure the amount of fluid that your drain (assuming you thought the level was correct prior to the service) all you need to do is add the same amount back in and youre done.
This should simplify the service and cut down on the time.
I tried previously to add an AN fitting and a braided line in the same manner except it would be permanent but the placement of the fill hole and the access to it puts the line near one of the Cats and I wasnt confident the line would hold up to the heat so I removed it.
I have a pic of the AN line and also the stock plug for reference.

Scott

Well done. I've got a burn scar on my wrist from 10 yrs ago doing the fill on a "dipstick-less" Cad 5L40 where the port was adjacent to the driver side exhaust pipe. What is the thread size on the transmission housing?

 

[MrHorspwer]

Mityvac MV7110

Works great for filling 6Lxx, 8Lxx, and 10Lxx transmissions (transfer cases and manual transmissions that use ATF too).

It's also an evacuator, so you can suck fluid out of the pan through the fill hole as well.

 

[64bawagon]

None of the other applications of this 10 spd have a dipstick you could swap in like the easy 6L90 fix?

No provisions that I can find. The sad part is that most of the real "Allison" transmissions have level sensors in them and can be checked electronically once the trans is at operating temp. The pushbutton units on the trucks at work were as simple as putting the truck in Neutral and pressing the Up and Down arrow simultaneously. It would the flash O L and either OK or Lo with a number of qts low.
Real Allison transmissions are built by serious people for serious people.... LOL

 

[64bawagon]

Mityvac MV7110

Works great for filling 6Lxx, 8Lxx, and 10Lxx transmissions (transfer cases and manual transmissions that use ATF too).

It's also an evacuator, so you can suck fluid out of the pan through the fill hole as well.

I am less than $15 all in on this setup. For a DIY'er like me it doesnt make sense to spend $200 on the Mightyvac. The first time I service this trans I am going to either replace the trans pan or have a drain welded into it while its off.

 

[CorvairGeek]

I have the 10 speed with the 6.2L gas engine. I have assumed the hole is not in the case (tiny dipstick, like the Ford variant), though it is obscured by a shield on the GM version. I've thought what these need is the dipstick added to the side of the pan, like GM did with the Corvair Powerglide and Pontiac Tempestorque transmission. When they adapted the Chevrolet Powerglide, the portion of the transimssion where the dipstick was removed. Simple and elegant solution that made them easy to service too.

 

[walterjay]

I pumped ATF into the side of my tranny with a $12.00 bulb pump from HF. I worked great.

 

[nascarnation]

No provisions that I can find. The sad part is that most of the real "Allison" transmissions have level sensors in them and can be checked electronically once the trans is at operating temp. The pushbutton units on the trucks at work were as simple as putting the truck in Neutral and pressing the Up and Down arrow simultaneously. It would the flash O L and either OK or Lo with a number of qts low.
Real Allison transmissions are built by serious people for serious people.... LOL

My name is one of the four on the patent for that system (1994)....although it's long ago expired.

 

[Fabulous50s]

I've put many of the $8 Dorman universal piggyback drain plugs in transmission pans. Highly recommended.

 

[64bawagon]

The pan is non magnetic so I am assuming its aluminum. I am hoping by the time it needs servicing that someone will either have a new pan with a drain plug in it or that I find an aluminum bung and plug that can be welded in.