This article was submitted by Tom Fraley aka MountaineerTom. Thanks Tom!
This guide covers a fluid and filter change on a ‘99 Silverado with the 4L60E deep pan transmission. The deep pans have a portion of the pan that hangs down lower, making in deeper.
I used a NAPA filter kit, p/n 1-9750, which included the filter, seal, and a cork gasket. I don’t prefer the cork gaskets, so I bought a rubber one while I was there. The p/n was 1-7381. Since GM seems to have severely over torqued the drain plugs from the factory, I decided to pick one up from the local dealer. The p/n for the drain plug is 24213991.
The tools needed are:
- a ratchet (I used all 3/8 drive tools)
- 15mm socket for the drain plug
- 13mm socket for the pan bolts
- 3 inch and/or 6 inch extension
- universal joint
- hook type tool to pull the seal out of the transmission housing
- T40 torx bit for the 2 screws that hold the shift cable bracket to the transmission housing
- rags and a big drain pan.
I goofed up a little and loosened the pan bolts before removing the shift cable bracket, which made it a little messier. So to make it a little less messy to start with, first remove the 2 torx screws holding the bracket. It just needs to be removed so you have more room to remove the pan. Some have just bent it out of the way, but I preferred to take the screws out and move it out of the way. You have to get at the screws from the top.
If you can, remove the drain plug with the 15mm socket so that the fluid is out when removing the pan. If it won’t come out, just loosen up the bolts on either the front or back side and completely remove all the rest, then you can tip one end of the pan down to drain as much fluid as possible from the pan prior to taking off the transmission housing. It will be a bit messy doing it that way, but it works fine.
Once all the pan bolts are removed, carefully pull the pan off. Be careful and don’t catch it on any parts in the transmission that cold possibly break. Once it’s removed, you’ll be able to see the filter.
Grab the filter and pull it straight down. It may be kind of tough, but it will come out. Be ready for a bunch of fluid to come out too. When the filter is off, you’ll see the seal inside the hole the filter goes into.
The seal on mine was extremely hard to get out. It wouldn’t budge. Some have had luck just pulling it out with a hook type of screwdriver, but I couldn’t get mine to move. I removed as much of the rubber from the seal as I could and then took a triangle shaped file and used it to cut a groove in the inside part of the metal. Be very careful and don’t file into the transmission housing if you do this. Also be careful if using the hook type screwdriver. You don’t want to gouge or scratch the transmission housing. After I filed a little while on it, it weakened it enough that I was able to get it out with the hook.
After the old seal is out, put a little clean fluid on the inside and outside of the new seal. Place it in the transmission housing push it in evenly as far as you can by hand. You can use a socket that is the same diameter as the seal, or use a punch and tap it in evenly around the seal until it is seated in the housing. It’s almost flush with the housing when all the way in. Just look at the original one before you remove it, and install the new one as far as the old one was. Some leave the old seal in because it is so hard to get out, but it’s not recommended. One the seal is in, push the new filter in until it is seated all the way in.
Now you can move to the pan. There is usually a pretty good bit of sludge in the pan and on the magnet. You can see where I run my finger across the magnet. Just pull the magnet of and clean it and the pan up really well. I used some parts cleaner and a clean rag to clean it up with, and then blew it out with some air from an air compressor to make sure there were no small pieces of lint in the pan.
To remove the stuck drain plug, I tried two methods. First I tried using some screw/bolt extractors (I’ve always call them “easy outs”). Start by drilling as small of a hole as possible, then step a couple sizes to make the hole a little bigger each time. Once you get the hole the size you need for your easy out to fit in, clamp the easy out in some vise grips, put the end of the easy out in the hole, hit the top of it with a hammer while you turn the vise grips in a loosening motion.
Those work pretty well, but I happen to break the easy out off in the screw, so I went to plan “B”. I used a Craftsman bolt extractor that fit tightly over the bolt head. You have to tap it on with a hammer to get it to fit tightly. They took a wrench and turned the bolt extractor and it came out with a little force.
Reinstall the gasket and pan making sure the gasket is laying flat on the pan, tighten the pan bolts hand tight. When all are hand tight, torque them in a crisscross pattern to 8 foot pound (Haynes manual). You want to crisscross them so the pressure is distributed evenly. Install the drain plug and torque to 13 foot pounds (Haynes manual). Align the shift cable bracket and install the 2 torx screws. The Haynes manual didn’t have a torque for these, so I just snugged them up good and tight.
Next is refilling with transmission fluid. Make sure you use the correct kind. Mine called for Dextron III. Start the engine and let it idle for 5 minutes. Pour in enough fluid to raise the level to the cold mark on the dipstick. Move the shifter all the way to 1 for few seconds, then 2 for few seconds, and so on, until it is in Park. Then check you fluid level again. Add a little at a time until you get to the cold mark. Just be sure you don’t over fill it.
Drive 10 to 15 miles to get the transmission up to normal temperature, move you shifter through all the ranges again, and check your fluid level again to make sure it’s where it should be for the hot reading.
If you do find out that you’ve over filled the transmission, and you are able to remove your drain plug, you can loosen it up and crack it open just enough to let a little fluid drain out. Make sure the transmission fluid is not hot when you do this, or you could get burned. Make sure you go back through your procedures for checking the fluid level again.