Servicing the Power Seat Transmission

In this first picture, you can see that I have marked the location of the cables in regard to location on the transmission. This is an important step, because if you don't have the cables in there proper location, the seat switch will not function as designed.



Next is to remove the cable retainers on both sides of the transmission. Note that there are 2 yellow cables. This is because one is a replacement. The cable colors determine the lengths of the cables. There are a total of 3 colors and 6 lengths.





Note that the cable end are in poor condition, so they will be either repaired or replaced, depending on availability and amount of damage. The terminal connector on this transmission is also damaged, and a replacement isn't available but it is still serviceable as is.

Here you can see the transmission with the cables and cable retainer removed. There are 2 screws that hold the cables onto the transmission.



Here I have separated the two halves of the transmission, for inspection, cleaning, and repair. There are a total of 3 screws that hold the two halves of this assembly together. Once removed, the halves separate easily. You can also see that sand has infiltrated the unit, and if not completely removed, it will destroy the plastic gears.



In this picture, I have marked the gears locations with a black marker. There is one small gear, and 2 larger gears which are identical.

Next, I have removed the gear, shaft, cog, and spring assemblies as a unit. All parts are the same except for the gears, so you don't have to be concerned about getting them mixed up. There is a plastic thrust washer on each of the cogs, so be careful not to loose this small part. It can barely be seen and appears to be part of the cog until you clean the parts, where it will probably fall off. Clean the metal parts in a solvent to remove the hardened grease. I cleaned the gears with dish washing solution and a tooth brush. I found that there was some rust on the shafts, so I polished that off using grade # 0000 steel wool.



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Next is the transmission solenoid that needs to be cleaned. You will note that the clutch shaft cap and plunger assembly has hardened grease and rust on it. This requires that they be cleaned, and polished using the steel wool.



The last picture shows the shaft that connects the motor to the transmission, and drives the gears. I had to spray the shaft with a penetrating oil to get it out of its bore. Once removed, it was cleaned with dish washing liquid, and showed no signs of wear, other than having hardened grease on it.



I washed both case halves in dish washing liquid, rinsed well, and dried with a paper towel. Below is a picture of some of the cleaned parts prior to reassembly. I reassembled everything giving it a coat of light petroleum jelly (Vaseline). GM had originally used a lithium grease, but it tends to harden with age, so I don't use it usually.



Reassembly is pretty much straight forward. Just put it back together the way that it came apart.