Transmission Fluid Leaking from Speedo Drive / Cable
 

Alright, so I think I know the answer already, but I want to know before I crawl back under the car and get covered in transmission fluid (again).

I have a leak coming from the speedo cable. I have already replaced the o-ring for the speedo drive, and also the small black donut-shaped seal that fits into the speedo drive before the cable goes on.

These are the only two seals in the area, right? Is it possible for the cable to leak internally or something, necessitating replacement?

The speedo itself works fine. It's just very irritating having hot transmission fluid wick up the cable and make the cabin stink.

I'm not sure if maybe I installed the donut-shaped seal backwards or something.

Thanks, Chris.

yeah if the little seal isn't right the cable can wick oil up to the cluster, which is funny but annoying

Do you know offhand what direction the donut-shaped seal goes in?

It has a flat side and an open side. I think I put the open side towards the speedo drive and the flat side towards the cable, but I'm not 100% sure.

I don't see anything about it in the FSM. The Haynes manual just shows this:

https://cimg6.ibsrv.net/gimg/www.rx7...b44ca599c7.jpg

No indication of seal orientation.

I installed my speedo cable seal with the flat side out. Haven't had any problems with leaking.

Interesting. I'm pretty certain that's how I have it installed now, but it still leaks like a sieve. It leaks so much I found it dripping down behind my dash onto the floor-mat.

Going to have to jack it up as soon as I have time. Maybe I didn't tighten the cable down tight enough.

Thanks to both of you for the advice. I'll report back if I find anything interesting.

Take the seal out and bend it a little all around. Had some rings, that had a cut or crack that leaked. Putting some engine oil (used is good enough) on rubber rings helps getting it to the right position and keeping everything sealed correctly.

Thanks all for the input. I took it apart and the problem was really simple (and something I should have figured out when I had it apart last time).

The speedometer seal sits on a small shaft inside the speedo drive. The shaft tapers as it approaches the end of the threaded section where the cable mounts. I hadn't pushed the seal down, so it was floating around on the tapered section sealing nothing at all. All I did was take the speedo drive out, put a 10mm socket on the seal, and push it down gently until it seated.

Anyone reading this who intends to replace the seal is best advised to take care the first time and make sure it's seated. I will probably have to take my dash out of the car and disassemble it completely to get all the gear oil out (including disassembling the instrument cluster); the stuff is everywhere. And since gear oil smells like creosote + BO, you definitely want to get all of it.