I have the service records on this car, and the previous owner never flushed the transmission to any extent. With almost 83K on the odometer this 4T80e transmission was due for some service. First thing I noticed when I got it up in the air was that one of the 10mm pan bolts was missing. It didn't leak, but still a bit disturbing. I have metric fasteners in the hardware bins and quickly found a replacement.
I slowly loosened one side and the juice started flowing ....
This usually makes a BIG mess with normal drain pans (and I'm a notorious spiller), so I've opted to use a big wide plastic storage bin (the under the bed kind) when draining transmissions. Set on a small wide stool, it makes a perfect catch basin.
The two filter screens looked free and clean of debris and the fluid looked relatively clean -- dark, but not burnt and it smelled like new fluid. Pretty good for 80K+ miles.
Even the magnet in the bottom of the pan was pretty clean -- just a little bit of "Schmutz", but nothing to worry about.
The gasket and the screens were pretty brittle -- definitely on borrowed time here.
Now it was time to drain the upper part of the transmission housing -- the 4T80e has a separate drain plug for this purpose right next to the intake port for the large screen. This usually drains another 3 qts or so out of the upper housing.
Sorry for the bad closeup pics, but I accidentally set the damn camera on "night mode" -- and didn't realize it until everything was done.
Here's a pic of the plug location
The old pieces were removed and discarded -- they were pretty brittle.
To do this right, you need a proper pan gasket that has steel crush washers in each of the screw pockets. Nothing else will do, and that goes ESPECIALLY for the cheap AC/DELCO (and other generics) cork pan sets. These things are nothing but junk, and will make the transmission leak. I mistakenly ordered one from Rock Auto and I got what I paid for. $17 worth of useless cork junk. Luckily the local NAPA had exactly what I needed.
THIS!!.......
.......NOT this!
The OEM style NAPA gasket has two plastic alignment dowels molded into the gasket and they mate directly to two alignment bores in the transmission gasket flange. My finger is pointing to one of them.
The kit includes two rubber bore seals for the two new particle screens. They have to be installed in the bores first before then the screens are pushed in place. A little grease on the outside helps keep the seals in place while the screens are pushed home in the bores.
The pan is cleaned and dried, while transmission side sealing surface is cleaned and degreased with brake cleaner. Once that's done the pan is carefully reinstalled and tightened slowly and evenly in a criss-cross fashion -- and then finally tightened to 106 in/lbs.
The next step is to measure the fluid that was drained. Some time ago I purchased a 5 liter graduated pitcher on ebay for a few $$ and measure what's left in the drain pan -- turns out it was slightly above 5 liters.
I refill with a little bit more than 5-1/2 liters to account for some spillage and residual draining of the pan on the workbench, and take it for a 20 minute test drive.
Once back in the garage, I leave it in park and check the fluid level on the "HOT" marked side of the dipstick. It's another 1/2 liter low and that gets me into the middle of the "HOT" range that is marked on the stick. Good to go!!!! -- no leaks and it seems to shift a bit more quickly and evenly than before.
