1981 Trans Speedo Leak

[gambit]

I changed out my transmission speedo cable and after a few months it started leaking. I did not have it tight is what I found out, after I tightened it up it was ok for two weeks then started leaking again. Tightened up again and still a slight drip. Does anybody know if there is an o ring or gasket of some kind for the cable end, and I just didnt have one?

 

[wishuwerehere82]

No, there's a flared seal on the face of the speedo cable screw on thingy, like one on a garden hose, that seals against the tranny fitting. Even though it's tightened up real good, it still leaks a little. I'm tempted to smear some RTV on mine and be done with it.

 

[bmotojoe]

Mine did the same thing no matter how tight my cable was. I removed the speedometer cable and then the small bolt holding a flat clamp securing the speedometer driven gear fitting sleeve, then pulled out the speedometer driven gear fitting sleeve. There is an O ring on the outer housing of the gear fitting sleeve and removing the speedometer gear from the fitting there is a silicone cup seal inside the gear fitting sleeve. I went to my local auto parts house and they looked up the cup seal for me. I replaced the cup seal and reinstalled using a little transmission assembly grease around the shaft of the speedometer gear and the O ring on the outer housing.
This did not cure the problem, so I removed the speedometer cable and driven gear fitting sleeve again. After cleaning it up real good I found that there was a lot of slop between the speedometer gear shaft and the inside of the driven gear fitting sleeve. The original driven gear fitting sleeve was made out of aluminum and after time it just wore out. I looked at the prices of all the online vendors and then called my local Chevrolet Dealers parts department. I always tell them I belong to a Corvette Club and they give me 20% off. They had to order the driven gear fitting sleeve and O ring but had the gear in stock. All three items were picked up the next day and installed.
Read the directions when installing the cup seal in the driven gear fitting, as the placement of the seal is critical depending if the application is for a automatic or manual transmission.
This item from Ecklers is for a 4 speed but looks real similar to the automatic: http://www.ecklers.com/product.asp?pf_id=45170&dept_id=1873
Hope this helps,
Brian