FMX Transmission Leak Bell Housing

Got home from a cruise in and had a significant transmission leak under the car. Crawled under and its coming from inside the bell housing and leaking out of the inspection plate area. There has been a small oil leak before this and couldn't visually see it, but it appeared the oil was coming out of the inspection plate area. Transmission fluid is on my exhaust pipes so it looks like it leaking during operation.

Background: 351 Clev, 2V, FMX automatic. Just finished restoring the car so It hasn't been driven much since putting the engine and transmission back in around a year ago. Probably maybe have 100 miles on it due to the restoration. While we had it out we put in new rear main seals (replaced all seals), put in new fly wheel and torque converter.

Give me the bad news!

Frustrating as the car looks great and I'm dying to cruise in it and now this setback.

The most likely suspect is the front (input) seal. The other possibilities are the pump seal/gasket and a split torque converter weld.

Hi,

Where to get a very good quality input & output shaft/housing seal, part number/manufacturer please(still available by Ford dealer?).

Thanks for advice,

eddyw

Unfortunately you are going to have to drop the transmission to change out the front seal, it can be done in an afternoon taking your time though. I can pull an FMX in less than an hour without much difficulty.

Well, the crazy part is this is going to be 4th time we have had to drop it. We have replaced everything and pretty sure we had the front seal replaced when we put in the new torque converter. Sigh...but becoming an expert on dropping it.

Well, the crazy part is this is going to be 4th time we have had to drop it. We have replaced everything and pretty sure we had the front seal replaced when we put in the new torque converter. Sigh...but becoming an expert on dropping it.

Click to expand...

Yep. Looks like the front seal will need replacing. I know, more practice isn't what you had in mind...

I bit the bullet, dropped the transmission and having a complete rebuild done. Just don't want to drop the transmission again so hoping the rebuild will prevent me from doing it again.

A common mistake that happens when replacing rubber seals is ppl dont lube the rubber seal or

the shaft it is sealing resulting in a dry assembly and cooking the rubber seal quickly.

FMX's are a bit on the heavy side. I pulled one out of my 72 Coupe 25 years ago by myself when I was still young and in shape (well round is a shape), but an aluminum cased 5 speed is much nicer . . . .

My car is all numbers matching to include the transmission. Doing something different wasn't an option.

In addition to some oil or petro jelly I run a very thin amount of The Right Stuff around the mating surfaces too before I pound the seal into place. Takes up any imperfections in the matting surfaces. I hate leaks! Pep Boys or Advanced Auto parts carries these. The tail shaft seal I had a problem. Both places had the wrong one listed. Front seal was right though.

I am having the same leak from the bell housing inspection plate. It only leaks after driving over 50-75 miles. I would think the only thing it could be is the front seal. After driving 3 Saturday nights for about 30-40 miles each, no leak! Looks like a good winter project (add it to the list).

Thanks for all the good info.