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MG MGA - Transmission oil leaking

I have been leaking transmission oil from my MGA for about 4 months. It's always about 1/2 way between low and high and I fill it up again.

I cleaned up the transmission (was not that oily) an wiped the speedometer cable as it was wet with oil.

I filled it up and took the car for a long drive and after I put the car in the garage and looked underneath and there were a few drops. The next time I looked, the nextday, oil had run out into a stream over night but had stopped.

I put the car on jack stands and today I crawled under to find no more oil had run out (level is 1/2 between low and high on the dip stick). I could not find and major place where oil came out.

I did notice the speedometer cable was covered with oil and that there is a small hole where it rubbed next to part of the frame. After cleaning the cable again I moved the cable a little and found oil seeping out of the hole where it was worn away.

What I'm asking is it possible for the transmission oil to be coming out of the speedometer cable that much?

My next step is to put some dye in the transmission and see where the oil is coming from.

Any help or suggestions would appreciated.

David.....
David Honness

Yes, the speedo drive on the gearbox can have a leaky seal. You will need to buy a new seal of course, then drain the oil from the gearbox, because the speedo drive is below oil level.

Disconnect the speedo drive cable from the gearbox, then unscrew the large brass fitting and withdraw the fitting straight away with the drive gear and spindle. Be careful and be sure that the spindle and gear will come out with the brass fitting (and large copper seal washer). Life can get somewhat tricky if you drop the spindle inside the tail housing.

For picture and instruction to R&R the seal see here: http://mgaguru.com/mgtech/gearbox/gt106.htm
When all is reassembled, refill with oil.
Barney Gaylord

As an extra safeguard against dropping the spindle inside the tail housing as Barney describes, I get a length of the clear plastic tubing and push it tightly over the spindle. You can then use a ring spanner to undo / tighten the brass fitting.

Regards

Steven
S HILL

Barney,

I am seeing the oil coming from the speedometer housing where a hole was worn through about 14 inches from the end. I wasn't aware the the transmission oil could get up there. Is that because of the seal?

David....
David Honness

Yes. If the seal didn't leak there would be no oil in the cable jacket (except a small amount from originally assembly).
Barney Gaylord

Barney,

Thanks for the help.

David....
David Honness

This thread was discussed between 02/11/2008 and 03/11/2008

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This thread is from the archive. The Live MG MGA BBS is active now.