F-150 OD Drip

[JtownJoe]

I installed an 87 F-150 Tranny a few years ago and I have developed an annoying drip at the tranny to bellhousing joint. I was considering trying out either a Lucas type gear oil stop leak or one of the Penrite Products that I've heard work so well on the steering box leaks. Anyone have any experience with either products or thoughts on their use on modern std trannys? I'm not sure what to think of the fluid viscosity in the F-150 vs the SAE 85 - W 140 gear oil that I am currently using. I should add that it's not nearly bad enough to warrant tearing it apart, to find the actual cure, at least during the season when I get to enjoy running it.

[Mitch]

the fluid spec from ford is part # D8DZ-19C547-A which is 80W90 GL-4 gear oil

your already running a thicker oil in it. i wouldn't try the witches brew to plug the leak, you'll probably end up with hard shifting issues

just fix it right when u have the time..

[JtownJoe]

Thanx Mitch, I appreciate the input. I'm going to switch to the 80W90 GL-4 gear oil that is spec'd and I think I'll just live with until it's a winter project.

[1931 Flamingo]

Are you sure it's tranny fluid and not rear main??
Paul in CT

[JtownJoe]

Yes, it's thicker that the engine oil. Thanx

[plyfor]

had similar issue with my F150 tranny which was overfilled. lowered the level slightly and also repacked universal joint clamshells with corn head grease. Check as per post 3 if engine oil. The front seals on the F150's can be suspect as well.

[JtownJoe]

I will look at the level again and check for any sign of leak at the U-joint clams. I did find the speedo cable nut appears to be stripped and it could be contributing to some of the leak.