QuestionQUESTION: I have a leak under my 1980 Triumph Spitfire 1500. Assuming it was a leaking rear seal, I topped off the transmission with fluid, and the next morning there was a lot of fluid under the car. Did I read somewhere that the rear seal can be replaced without removing the transmission--simply disconnecting the output shaft from the driveshaft and jacking up the engine like you do when you pull and replace the transmission? And is there an obvious reason why a new rear seal would be leaking? Any advice would be appreciated.
ANSWER: You could try as you suggest, but I think prying out the rear transmission oil seal would be difficult; if you had a seal pry bar/tool, you might be able to do it.
However, just filling the case should not cause oil to come out the rear. The side fill port is the level to fill to, and without a transmission in front of me, I would have said that it is lower than the rear seal
Trace the leak if you can; the leak may be from the drain port, the case to tailshaft, or from the front of the transmission.
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QUESTION: You are right. I got the car jacked up and got underneath it. The rear seal area is clean and dry. There was fluid on the bottom of the gearbox. It is not leaking out from the bell housing; It seems to be coming from the rear, and possibly even the top of the gearbox. I'm not any kind of expert on Triumphs (or car repair in general). What is a drain port?
ANSWER: The transmission is 3 parts; the steel bell housing, a steel housing for the main gears, and an aluminum tail shaft.
On the center steel housing, there is the top cover (single rail), the side fill pipe plug, and drain pipe plug on the bottom side, center of the housing.
This bottom center pipe drain plug is usually where most transmissions leak first, as this is where the gear oil collects when not in motion. If you over-fill the transmission, above the level of the passenger side fill plug, you may get a leak from the side plug when not moving.
There is a gasket/seal between the steel center housing and the rear aluminum tail shaft that may also leak.
Use brake cleaner, and spray/wipe down the entire transmission underside. Get it down to the metal/paint, get all the grime or grease off the case. Note that brake cleaner may remove any paint as well.
Then check back later and see if you can trace the flow of oil on the case to see where the gear oil is leaking out.
Since transmission oil cirulation is not a pressure system, but rather splash lubrication, teflon tape on the pipe plugs and/or some red or back silicone gasket goop on the place where the case is leaking should be enough to stop the leak.
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QUESTION: I did what you said, and it appears the fluid is leaking from the gasket between the gearbox and rear tail shaft. I'll try to tighten those bolts up a bit more to see if that clears it up. If I have to again pull the transmission to get to the problem, could I use an RTV sealant there instead of a paper gasket?
AnswerAs the shift linkage connects to the tailshaft housing, alot of the linkage has to be disassembled on a single rail trans to put a new gasket.
I would suggest attempt to fix by leaving the trans in the car, cleaning the entire contour of the seal well with more cleaner & a toohbrush. Take RTV sealant and seal the lower 1/2 of the contour, thickly, and make a nice bead of sealant and smooth with your finger.
Then torque down the bolts, as some of the RTV may have gotten into the leak.
At best it would be a temporary fix, as vibration will likely cause it start leaking again. You can also try one the stop leak products that may swell the gasket to stop the leak.
