GM 4L80E Filter Replacement - In Middle of Job

[Westieterrier]

Happy Friday Gentlemen, I'm in the middle of replacing the tranny filter and fluid in my 1999 C2500 2WD Longbed w/ 10.5 HD rear, which hauls a sizable Lance Camper, ie, not a daily driver. It has a 152K and I bought it from the original owner (still in contact) and he doesn't remember if he ever changed the filter. The fluid looked old (dark red), but didn't smell burnt and there was no particles in it or in the bottom of the pan. The insides, from what I can tell looking at what I can see, look great. I have a few questions before I button it all up:

Filter Seal- I cannot seem to get the Filter Seal out despite using snap ring pliers; needle nose pliers; and (carefully) a screwdriver. I'm pretty ty sure I have to destroy it to get it out, and am worried about damaging the inside of the boss that's part of the transmission body if I try to pry. Like the pan gasket itself, which I am keeping, this seal seems to be in very good shape. I want to just leave it in there, like the pan gasket. What do you guys think?

Magnet: There's a magnet inside the pan on top of an indentation with squiggly lines (see pic). Is this from he factory? It looks like it belongs there, though I've never seen anything like it.

Pan Gasket: As per the service manual, I'm gonna leave the pan gasket in place, though I do have a new GM one. The filter and fluid are USA-made, but the new gasket is Mexico, though it seems very robust. In any event, the old one is in great shape. What do you guys think?

Drain Plug: Man, this short-shouldered bolt would not come out with hand tools and was a real PITA, esp. lying on my back. I took the pan off and removed it with my impact driver. I did a number on it with the hand tools on my first try, though it still looks serviceable (see pic). What is the minimum I can torque it down when I reinstall it? I do have a higher-shouldered magnetic replacement on its way, and will likely use that one if it's not Chinese crap.

Pan Finish: The finish on the outside of the pan is in such great condition, I almost thought it was aluminum! Man, what finish did GM put on these things??? It's been sitting under the truck in Oregon for 25 years and has 152,000 miles of rain, dirt, rocks, etc. I'm super impressed and would love to finish other parts under there in same as I go along. Of course, if it's some kind of powder coat (which wouldn't last that long anyway) that's probably out of the question. I'm just super curious if anyone knows specifically.

Thank you all in advance. This site is really awesome! P

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[Caman96]

I’d do this as well. There’s nothing like fresh fluid after 20+ years.

xc_hide_links_from_guests_guests_error_hide_media

 

[stutaeng]

You have to carefully put a flat screwdriver on that seal edge and strike the screwdriver with a hammer to collapse the metal part of the seal. It takes some effort. Work around it and it should pop off. I know the first time I did it it was frustrating, but after that you learn how to do it.

I seem to recall I saw somewhere on YouTube a video a guy said one of his viewers said to use a piece of threaded black iron pipe to remove it. Maybe 3/4"? He said it worked, but haven't tried it myself.

Everything else sounds good.

I learned a flush method from @Schurkey to get more fluid out of the torque converter. Works very well, just need to buy more fresh fluid. But that's a good thing.

Make sure to get the same filter, like the one it has there with the 4 little dimple feet, also known as the late style or deep pan filter.

 

[AuroraGirl]

Do you have a small chisel you can get up to the lip and then carefully collapse or cut through at a point? I used a small screw driver on my 4t65e, just pushed it in on itself in a single spot and then that took most of its holding force away

 

[454cid]

On the drain plug, I would recommend using a breaker bar instead of an impact next time.... one hand steadying the socket on the plug, and the other applying torque.

If the original gasket still looks good and wasn't leaking, sure clean it up and re-use it. I did with mine, but it was several years ago.

I think the pan finish is some kind of galvanizing, but I'm not sure of it.

 

[Caman96]

On the drain plug, I would recommend using a breaker bar instead of an impact next time.... one hand steadying the socket on the plug, and the other applying torque.

If the original gasket still looks good and wasn't leaking, sure clean it up and re-use it. I did with mine, but it was several years ago.

I think the pan finish is some kind of galvanizing, but I'm not sure of it.

^^^That and don’t use either when re-installing plug.

 

[454cid]

^^^That and don’t use either when re-installing plug.

Right.... I'd actually reccomend a torque wrench for re-installing, if concerned with over-tightening.

 

[east302]

I used this slide hammer from Harbor Freight to get the filter seal out of my 4l60e. Worked like a charm, just be careful with the fingers on it in the bore.

You must be registered for see images attach

 

[Erik the Awful]

Filter Seal- What do you guys think?
Magnet: Is this from he factory?
Pan Gasket: What do you guys think?
Drain Plug: What is the minimum I can torque it down when I reinstall it?
Pan Finish: Man, what finish did GM put on these things?

Lots of good advice on the filter seal. I'd add to absolutely take the time to replace it. I agree with east302's pilot bearing slide hammer recommendation, but if that doesn't get it, using a screwdriver to collapse it inwards is probably the next best option. stutaeng's black iron pipe idea sounds solid as well.

Yes, the magnet is factory. If you ever replace your pan, be sure and transfer it to the new pan.

Absolutely replace the pan gasket. "Made in Mexico" doesn't mean deficient. There's plenty of garbage being produced here at home.

Either replace the drain plug or torque it to spec. You don't want it falling out. Looking at the picture, the hex doesn't look damaged, but it is very shallow. Be sure and get your socket square on it when you tighten.

I think the pans are galvanized.

 

[454cid]

Absolutely replace the pan gasket.

Do you not like the re-usable design? They're available new, but a lot of the replacements are the traditional one-time-use variety.