Tuesday, March 6, 2012
Lessons in Powerglide Rebuilding
Over the last few days, I’ve learned quite a bit about the GM Powerglide automatic transmission (PG).
First, the version used in Corvairs has smaller components than the PG used in their other cars and trucks. Second, the phrase, “penny wise, pound foolish” can be applied to my decision to save thirty dollars and buy the rebuild kit from a non-Corvair vendor. Third, it’s important to ensure all replacement parts are correct before proceeding with a rebuild. These three lessons became painfully clear when I discovered many of the gaskets and seals in the kit I’d purchased from a Finditparts.com (the one their website said would fit all PGs including those used on Corvairs) were not the right size for Ringo’s replacement transmission. The first seal I tried to install was too large for the groove it needed to fit in so I used the correct seal from an old partial rebuild kit that had arrived at my garage in Glinda’s trunk. Continuing on, I was in good shape until I went to install the paper gasket between the front pump body and the front pump cover. It was about an eighth of an inch too large in diameter. Sadly, the partial kit was missing this piece. At this point I had the choice to just buy the right gasket from Clark’s and button everything up or take everything apart, return the kit to the Finditparts.com, buy the correct kit from Clark’s and reassemble AGAIN the PG. Not knowing whether any of the half-dozen seals I’d used from the wrong kit were incorrect, I decided to go with the second choice. Yesterday morning I placed a call to Finditparts.com for a return authorization (which they granted without issue) and then ordered the correct kit from Clark’s. It should be here by the weekend. In the meantime, my garage time will be spent separating Ringo from his drivetrain.
Other highlights and lessons learned from the weekend of tranny overhauling included:
-Do NOT try to use large c-clamps to compress the springs in a clutch. Instead use a press; even if it’s a jury-rigged drill press, it’ll do the job.
-It takes three different pieces of documentation to fully understand how a PG goes back together (1961 manual, 1965 manual, and a hardcopy of GM’s instructional filmstrip).
-Even with three different pieces of documentation, take copious photos. I referred back to the ones I took during disassembly a few times.
-More than a shower is required to rid one’s hands of the distinctive aroma caused by a cocktail of ATF, solvent, and heavy duty hand cleaner.