Transmission fluid very high - options?

[BigDav782]

Still getting to know this truck, so checking fluid levels is high on the list. Checked the transmission fluid, and it is very high - at least a couple of inches higher than the range marked on the dipstick. I tried this in several scenarios: right after a long drive, 30 minutes after a long drive, and cold. All of those scenarios had fluid that was way out of range.

The fluid looks good (clean red color), so I have to assume it was changed and simply overfilled.

In that case, do I have any options besides dropping the pan? Can I suck it out through the filler tube instead?

If I do have to drop the pan, is now the time to get a new pan with a drain?

 

[Gary Lewis]

It doesn't sound like you are checking the level correctly. In Driveline/Transmissions/Automatic Transmissions/General Automatic Transmission Service you'll find:

Checking Procedure

1. With transmission in Park, engine at curb idle rpm, foot brakes applied and vehicle on level surface, move the transmission selector lever through each range. Allow time in each range to engage transmission, return to Park, and apply parking brake fully. Do not turn off the engine during the fluid level check.

2. Clean all dirt from the transmission fluid dipstick cap, before removing the dipstick from the filler tube.

3. Pull the dipstick out of the tube, wipe it clean, and push all the way back into the tube. Be sure it is fully seated.

4. Pull the dipstick out of the tube again and check the fluid level.

If the fluid is very red and doesn't smell burned you are probably ok. However, if you ever drop the pan and experience the MESS you'll make I'll bet you won't go back on with the pan until you put a drain plug in it.

[BigDav782]

It doesn't sound like you are checking the level correctly. In Driveline/Transmissions/Automatic Transmissions/General Automatic Transmission Service you'll find:

Checking Procedure

1. With transmission in Park, engine at curb idle rpm, foot brakes applied and vehicle on level surface, move the transmission selector lever through each range. Allow time in each range to engage transmission, return to Park, and apply parking brake fully. Do not turn off the engine during the fluid level check.

2. Clean all dirt from the transmission fluid dipstick cap, before removing the dipstick from the filler tube.

3. Pull the dipstick out of the tube, wipe it clean, and push all the way back into the tube. Be sure it is fully seated.

4. Pull the dipstick out of the tube again and check the fluid level.

If the fluid is very red and doesn't smell burned you are probably ok. However, if you ever drop the pan and experience the MESS you'll make I'll bet you won't go back on with the pan until you put a drain plug in it.

Thanks Gary. I did follow that procedure to the letter, except I couldn't put the parking brake on (it's frozen - I'm sure that's a future adventure). In addition, I believe that my original owner's manual had information about leaving it sit for a bit if it had been driven with lots of stop-and-go traffic (which it had), and also that it is OK to check it when room temperature, but that it isn't as good of a check. All three gave very high levels.

Any recommendations on where to get a pan with a drain, or do people install a drain in their OEM pans?

[Gary Lewis]

Thanks Gary. I did follow that procedure to the letter, except I couldn't put the parking brake on (it's frozen - I'm sure that's a future adventure). In addition, I believe that my original owner's manual had information about leaving it sit for a bit if it had been driven with lots of stop-and-go traffic (which it had), and also that it is OK to check it when room temperature, but that it isn't as good of a check. All three gave very high levels.

Any recommendations on where to get a pan with a drain, or do people install a drain in their OEM pans?

Sorry, I misunderstood. Glad you followed the directions.

If you just have too much fluid but think the fluid is good, I'd stick a suction gun's tube down the filler tube and suck some out until it reads correctly. Or, you can pull the inspection plate at the bottom of the flywheel, rotate the crank until the 1/8" pipe plug shows up, and loosen it to drain off some. I'd do that LONG before I pulled the pan if the fluid is good.

But, if you want to replace the pan, meaning you are a glutton for punishment, then do a search of this forum. The topic has been discussed quite a bit very recently.

To do that search, scroll up to just below the blue pickup and you'll see an empty field with a spy glass in it. Type in something like "transmission pan", make sure the Everywhere button is pushed, and click Search. That will return every post where "transmission" and "pan" were used, and there are plenty of them.

[Dorsai]

Any recommendations on where to get a pan with a drain, or do people install a drain in their OEM pans?

I just did this exact job (replacing my stock pan with one with a drain) on my truck earlier this month - it wasn't a difficult task, but it was extremely messy.

You have a C6 transmission, right? If so then we use the same parts...here's what I used:

Transmission pan w/drain

Transmission gasket

Transmission filter

I haven't driven my truck but maybe 50 miles since I did the work (I'm prepping for a road trip in a few weeks, so it's been down a lot for preventive maintenance), but everything seems fine from a transmission perspective - no mechanical complaints, no leaks, no nothing. My only gripe with any of it was that I didn't care for the hard plastic washer for the drain plug on the new pan, so I picked up a softer neoprene one from Ace and used that instead. Worked great.

 

[grumpin]

Any recommendations on where to get a pan with a drain, or do people install a drain in their OEM pans?

I just did this exact job (replacing my stock pan with one with a drain) on my truck earlier this month - it wasn't a difficult task, but it was extremely messy.

You have a C6 transmission, right? If so then we use the same parts...here's what I used:

Transmission pan w/drain

Transmission gasket

Transmission filter

I haven't driven my truck but maybe 50 miles since I did the work (I'm prepping for a road trip in a few weeks, so it's been down a lot for preventive maintenance), but everything seems fine from a transmission perspective - no mechanical complaints, no leaks, no nothing. My only gripe with any of it was that I didn't care for the hard plastic washer for the drain plug on the new pan, so I picked up a softer neoprene one from Ace and used that instead. Worked great.

Nice info Matthew! I have that gasket and after looking at the drain pan you linked, I think that’s a must have!

[kramttocs]

Nice info Matthew! I have that gasket and after looking at the drain pan you linked, I think that’s a must have!

Any drain pan is a great upgrade and I would consider the TCI pan if the truck's usage justifies the cost. High capacity and deep finned.

Liquivac makes a nice little suction pump with container that I used when swapping pans. Really takes the mess out of jobs like this.

[grumpin]

Any drain pan is a great upgrade and I would consider the TCI pan if the truck's usage justifies the cost. High capacity and deep finned.

Liquivac makes a nice little suction pump with container that I used when swapping pans. Really takes the mess out of jobs like this.

More good tips! I like that Liquivac!

[Gary Lewis]

More good tips! I like that Liquivac!

Yes! I never thought of draining the whole transmission via the dipstick tube, but I just suggested lowering the level that way.

 

[BigDav782]

Yes! I never thought of draining the whole transmission via the dipstick tube, but I just suggested lowering the level that way.

I did use my Mityvac (hand operated deal, usually for bleeding brakes), and pulled out a couple of quarts in short order, through the dipstick tube. It's slow and labor-intensive, but pretty easy. The fluid looks black, so I'll probably focus on changing it now.