How do i change the transmission gasket on a 1988 chevy Silverado

Changing the transmission gasket on any car..
You need to drain the transmission fluid - if you get under the car you will see the transmission pan drain plug.

Drain the transmission fluid and then remove the small bolts that hold the fluid pan to the transmission body. You may need a blunt screw driver to break the seal/lever the pan off. Be careful when levering as you don't want to damage the mating surface of the fluid pan.

With the fluid pan removed use a blunt screwdriver to scrape off the old gasket from the pan and the transmission body. Apply a thin smear of sealant to the pan and place the new gasket onto it - line up the holes in the gasket with the bolt holes in the pan.

Lift the pan up against the transmission body and put the bolts in finger tight to hold it into place, then tighten with a socket to pull the pan tight against the transmission body.

To refill the transmission with fresh fluid (don't use the old fluid) have a look on the side of the transmission itself. There will be a filler plug that needs to be unscrewed. Alternatively, you can rig up a funnel/tube and fill the transmission via the transmission dipstick tube. This method takes longer but it tends not to be as messy as filling the transmission via the filler plug.

However, before you start any work on the transmission gasket check that it is actually that gasket at fault. Fluid above/in front the transmission pan can point towards a leaking torque converter.

Check the sensors on the transmission. May just be corrosion on the sensors or it may be a faulty sensor. Also, the torque converter bearing may have went bad due to the running it on low transmission fluid.

Should be located on the Drivers side of the Transmission close to the Floorboard from underneath the vehicle.

I believe up to 1992 !

It sounds like the transmission front pump seal, if thats the case the trans. has to be pulled out to replace the seal.It will not be a cheap fix at a shop good guess around 200-500$ est.

The switch is mounted on the side of the transmission. There is some adjustment range by loosening the mount screws and rotate the switch until the lites come on when in reverse.

no need, just drop the pan and replace filters and gaskets. add 4 qts start and check fluid level, add till full

Only if its a 3 spd tranny. If O/D then check tv cable on carb. If good you can check gov also. Whats fluid look/ smell like?

got a clutch pedal in there? If auto, it could be a 700r4 or some variation of that. You can likely get exact info from a dealer if you give them the vin #.

Make sure your transmission fluid is up to level, if it is, put a little bit on your fingers from the dipstick, does it smell burnt? if your unsure rub it between your fingers if it looks more black than red and feels gritty its burnt, try changing fluid and filter if that doesnt help your forward clutches are out, ive had some luck with trans-X in situations like this but its rare that it helps and almost never lasts hope i could help