Frpp alu driveshaft is leaking, not the tranny seal. Ideas???

VladasapSVT · Jan 30, 2012

Hey guys,

Just installed a "new to me" frpp aluminum driveshaft and i kept on smelling tranny fluid. I looked under and voila, the d/s is leaking.

However its not the rear trans sealor bushing. The seal is nice and dry, seems like the fluid is leaking somewhere around u-joint.

Ideas on how to seal this up and elwhere's the leak coming from is what confuses me the most honestly...

*This is on a 94 cobra if it makes any difference with a T5 of course.

justinschmidt1 · Jan 30, 2012

This reminds me of when my muffler fluid was low.

Im not sure what your talking about but it has to be leaking from one of the seals or maybe from the yoke seal?

Is it coming from the front or rear?

can you get a picture of this leak?

ujoints have grease in them...it shouldnt even be in liquid form

Musturd · Jan 30, 2012

Hmm did the yoke have a big groove in it pull drive shaft an get a picture of the yoke please

rz5.0 · Jan 30, 2012

Ive heard of this before.. Leaks out the yoke... Get it weldef or a diffrent one...

VladasapSVT · Jan 31, 2012

The yolk is completely dry as is the seal as well as the 1"-1.5" of the yolk that sticks out of the tranny. Not greasy or anything. Bone dry.

However, right where the u-joint is, is all wet. Looking at the tub where the fluid gets splattered onto, its directly inline with the u-joint. It seems like its leaking somewhere RIGHT before the u-joint.

Initially on first thought i thought it was fluid that leaked out a bit when i was installing the new one. So i cleaned it all up very thoroughly, drove 50 miles yest and allll wet again. Once agin, the actual seal and the little bit of the shaft (1" or so) are totally dry. But when i touch the u-joint and around it, all wet. For a second i thought a cap of the u-joint spit some grease out, but nope. This is tranny fluid.

Does fluid go into the rear of the yolk somewhere and is leaking from there???

Sorry for no pics guys but i just got home and saw your posts and the garage where i keep the mustang is a mile down...

justinschmidt1 said:
Im not sure what your talking about but it has to be leaking from one of the seals or maybe from the yoke seal?

What is and where is the yolk seal you referring to????

Musturd · Jan 31, 2012

Pull the drive shaft out ... Check the yoke for cracks or grooves I don't understand how that could be happening

GDTrumbo · Jan 31, 2012

At the back of the yolk (u-joint end) there is a plug. This plug kinda resembles a freeze out plug in an engine block. You will have to look up between the u-joint and the butt end of the yolk to see it real well.

During the manufacturing of the yolks splines, a pilot hole is bored completely through the yolk and the splines are machined. The last thing added to complete the part is a plug at the rear. I had this plug fall out on my '69 Road Runner. Leaked like a pig!

We just disassembled the front u-joint and welded a round flat piece of 1/16" steel into the small well that the OEM plug fit into and that was it. Problem solved. It'll be a little different as your welding aluminum but no real biggie..............

GT

rz5.0 · Jan 31, 2012

GDTrumbo said:
At the back of the yolk (u-joint end) there is a plug. This plug kinda resembles a freeze out plug in an engine block. You will have to look up between the u-joint and the butt end of the yolk to see it real well.

During the manufacturing of the yolks splines, a pilot hole is bored completely through the yolk and the splines are machined. The last thing added to complete the part is a plug at the rear. I had this plug fall out on my '69 Road Runner. Leaked like a pig!

We just disassembled the front u-joint and welded a round flat piece of 1/16" steel into the small well that the OEM plug fit into and that was it. Problem solved. It'll be a little different as your welding aluminum but no real biggie..............

GT

This.... see pic on my above post

VladasapSVT · Jan 31, 2012

Do you think i can silicone that sucker up ir is welding it up my only choice?

Lastly, any way that this can be done with the d/s in the car?

Musturd · Jan 31, 2012

No just take it out ur going to have to pull the yoke off the drive shaft most likely quit being lazy its 4 bolts for fuck sakes.... If you keep driving it you'll have no tranny fluid and a cooked tranny I'd just buy a new yoke for the 40 bucks it costs but that's just me .. Silicone you'd have to clean it so good because it will never stick to tranny fluid... For the 5 mins it takes to pull the drive shaft once the cars in the air is it really worth a 500 dollar tranny..

rz5.0 · Jan 31, 2012

If it was me id get another yolk but its your choice.. I would remove the drive shaft be sure to mark it..

VladasapSVT · Jan 31, 2012

Ill take it out, holy moly, peeps are getting fiesty. Im just gonna do this after work and i typically dont have more than 5-10 mins...

I think that what im gonna do is put the original yoke on the aluminum d/s, they are the same if i remember correctly, yes?

And what do you mean, mark the d/s? The yoke is grooved specifically so it can only go in one way, when i popped the this one in, i just didnt move the pinion nor tranny and this one could only fit one way.

Are you maybe referring the yoke and the driveshaft when i swap the 2 yokes?

rz5.0 · Jan 31, 2012

Never mind then.. With the stock d/s you mark it on the pinion flange..

GDTrumbo · Feb 2, 2012

Well crap! How did I miss that pic. A picture is worth 1000 words..................

GT

rz5.0 · Feb 2, 2012

GDTrumbo said:
Well crap! How did I miss that pic. A picture is worth 1000 words..................

GT

i was in the process of geting the pic as you posted your reply see the edit I posted a few minutes after your reply.. Thats y I went back and quoted you.. Not trying to steal all the credit....

DFG_magic · Feb 3, 2012

If it does end up being the yoke, make sure you replace your tailshaft seal and bushing while you're at it. Ford Racing part number for the correct yoke for your driveshaft is M-4841-B.

VladasapSVT · Feb 9, 2012

First of all, thank you all for your input. I really appreciate it guys!

Also, ive been soooo busy that i havent touched the cobra but ill sneak it into the shop after work tomorrow and swap the yokes and top off the trans fluid.

Thank you all again!

VladasapSVT · Feb 15, 2012

UPDATE:

Its been a few days since i swapped my old yoke onto the alu d/s and no more leaks!!! It indeed was the frpp yoke that was leaking in the back, right at the plug for that pilot hole.

Thank you guys!!!

*hope this helps someone in the future