Speedometer Cable Leak

[money pit]

I just had a rebuilt 727 trans installed. It seems to be leaking from the speedometer cable. I had this problem on a previous trans, that was never resolved. The gear was replaced. Is there a seal around the shaft of the gear? gear. Also, there is a leak at the front of the pan. It doesn't look like the gasket is leaking. My trans guy is going to fix the problem. I just wanted to know if there is something I need to know about this issue. Thanks.

 

[Ronbo73]

I just had a rebuilt 727 trans installed. It seems to be leaking from the speedometer cable. I had this problem on a previous trans, that was never resolved. The gear was replaced. Is there a seal around the shaft of the gear? gear. Also, there is a leak at the front of the pan. It doesn't look like the gasket is leaking. My trans guy is going to fix the problem. I just wanted to know if there is something I need to know about this issue. Thanks.

View attachment 140188

View attachment 140189

There is a o-ring/seal inside the speedometer cable housing. Mine was also leaking from there , I replaced it and no more leak. I don't remember where I bought the o-ring/seal. I will try to find my receipt and let you know.

 

[Vaanth]

I just had a rebuilt 727 trans installed. It seems to be leaking from the speedometer cable. I had this problem on a previous trans, that was never resolved. The gear was replaced. Is there a seal around the shaft of the gear? gear. Also, there is a leak at the front of the pan. It doesn't look like the gasket is leaking. My trans guy is going to fix the problem. I just wanted to know if there is something I need to know about this issue. Thanks.

View attachment 140188

View attachment 140189

The speedometer pinion gear shaft inside the adapter, onto which the speedometer inner cable connects, has a seal as shown in the following diagram from the factory service manual:

The small seal might be missing, worn, cocked in the bore, or installed backwards.

The fluid showing on the pan could be the pan gasket, but might be from an area above that has ran down along the pan edge such as the speedometer adapter, the shift shaft seal, a leak at a cooler line fitting, a leak at the front band adjustment, the dipstick tube o-ring, or a leak at the rear low/reverse band strut o-ring.

 

[money pit]

The speedometer pinion gear shaft inside the adapter, onto which the speedometer inner cable connects, has a seal as shown in the following diagram from the factory service manual:
View attachment 140208

The small seal might be missing, worn, cocked in the bore, or installed backwards.

The fluid showing on the pan could be the pan gasket, but might be from an area above that has ran down along the pan edge such as the speedometer adapter, the shift shaft seal, a leak at a cooler line fitting, a leak at the front band adjustment, the dipstick tube o-ring, or a leak at the rear low/reverse band strut o-ring.

Thanks very much. Very helpful info. I'm taking my car this week to get it checked out. I'll keep you posted.

 

[money pit]

There is a o-ring/seal inside the speedometer cable housing. Mine was also leaking from there , I replaced it and no more leak. I don't remember where I bought the o-ring/seal. I will try to find my receipt and let you know.

Thanks. I'll go online and see if I can find a seal.

 

[Steve340]

Brewers sell the seal and installation tool.