Transmission Removal for the 3rd Time…
Hopefully the saying “the third time’s the charm” holds true. On Tuesday I found myself tackling transmission removal yet again. Why? Because the transmission was leaking. The last two times I’ve had the car in the air, I’ve noticed a drop of fluid on the bottom of the case. I clean it off, it comes back, and there’s no good reason.
My reasoning for pulling the trans went as follows: if the transmission is seeping now when the fluid is cold, it’s gonna be dripping once I drive the car and the fluid warms up. And I hate leaks. Transmission removal is usually a bitch for the average hobbyist. And if I had to do it lying on my back like I did when I put it in the first time, it would be. But with a lift and a transmission jack? It took me maybe 45 minutes to get it out, and that made doing the job right and sealing the transmission properly a no-brainer.
Tremec / Borg-Warner T5 transmissions are a modern design and don’t have many leak paths compared to earlier manual transmissions. Sure, there are the usual drain/fill plug issues, and the rear and front seals do wear out. The main area of concern, though, is where the tail shaft housing meets the main case.
A New Approach to Sealing the Transmission
The Tremec service manual recommends joining the two housings using neutral-cure RTV Lactate 598 (sic.) I assume that’s a typo and that they meant Loctite 598, which is exactly what I used when I rebuilt the transmission. The thing is, the housings are precision milled surfaces, so when you squeeze the case halves together you push out the RTV. After pulling the thing apart, that remains my best guess as to how and why the trans was leaking.
A quick search of the internet turned up videos by Paul Cangialosi, who wrote a book on rebuilding T5’s. He’s got a very helpful video on sealing T5’s. The main take-away: Paul isn’t a fan of RTV. Instead, he recommends anaerobic sealant, so I’ll be giving that a try this time to see if I can get a better result. I ordered the Permatex product instead of the Dynatex he recommends, mostly because I could get it faster. Hopefully if I follow his recommendations I can stop the leaks once and for all. We shall see!