Currie 9 inch w/ explorer disks, Detroit locker. Large style tapared roller bearing on 31 spline shafts (the Timken set is part no. U365L for the race and U399A for the bearings).
Why the hell are both sides leaking like there's no seal there? I mean like when I put a quart in I just watch it pour (not drip, pour) out each end of the tubes.
Breather tube is OK. Removed shafts and seals are not torn, and look like they did not fold under. I just put them back in am not driving it for now.
This started after the rear shafts were replaced, a shop did the work because this was part of a front end swap (went to bigger bolt pattern, needed new shafts) and I'm not up to the welding work needed.
I pulled the shafts myself after the leak began and it seems as if they put some kind of thin layer of RTV or something under the races. This can't be right, can it?
Any other ideas?

Ok, your talking Big Ford (new style) bearing end , using tapered roller bearingsCheck pic if unsure (http://www.superford.org/registry/users/208/144/housingflange.gif) This would be a Timken A20 set. The outer rubber seal, that fits in the axle tube it self can some times not seal real well., Yes I've RTV'd them more than a few times.. Are you sure it's not the axle shaft portion of the seal? If they are custom axle shafts, were they turned and finish machined at the correct spot for where the seal rides?

Big Ford new style. Looks like I'll be pulling them again to check the seal to shaft seal.
They were custom shafts.
Hope to hell its not the shaft, that would suck.
Thanks.

Mine did that at one time. Had to use silicone to seal the seal into the housing. Seems the housing started to wear where the seal seats. Don't overfill the housing either or it will pour out the seals.

Didn't pull the shafts last night, hopefully today. I also realized I checked the breather tube by taking it off the diff and blowing through it - duh - that doesn't check for an obstruction in the metal portion of the breather at the diff. Hopefully its that.
A guy also told me that even if the axles were machined to the right diameter, sometimes custom axles do not get smoothed over properly, leaving a thread like pattern from the lathe, which acts like a corkscrew to pull the fluid out past the seal.
If so - can it be machined smooth or am I fawked?
thanks

It should be able to be machined smooth, as long as they don't take too much. If the axles are not right, then who ever made them should make them right at no cost to you. Did they also press the bearings on?

are the inner seals in the correct way? who's axles? The timkin bearing should do the sealing alone and the iner seal should be able to do it as well I would guess the axles are not machined correcly. My next area of concern would be the housing ends.
HTH good luck

Inner seal? Now I'm confused. I'm looking at the bearing/seal set right now - the seal is a single round piece with an outer lip that fits over part of the race and part of the bearing cage, and when in place that outer lip seals (or is supposed to seal) to the axle housing. The inner section is supposed to fit tight around the axle shaft, its got a little round spring in there to keep it tight (spring wraps around the axle shaft with seal under it).
Is that what you mean by inner seal? That part with the spring? That's my concern on the shafts - that's where the problem would be if the shafts were not machined correctly.
Currie made them and sent them with the bearings pressed on. I had needed to go to 5 on 5.5 bolt pattern. The axle had been fine (leak free) with the 5 on 4.5 shafts in there, except the time I tore a seal when I had to pull the center section, but replacing the bearing set and putting the shaft back in properly had fixed the problem.
Thanks for all the helpful replies, hopefully I'll be abel to get it apart tonight, and hopefully like I said its the breather at the diff.

Originally posted by Lucy's Driver
Inner seal? Now I'm confused. I'm looking at the bearing/seal set right now - the seal is a single round piece with an outer lip that fits over part of the race and part of the bearing cage, and when in place that outer lip seals (or is supposed to seal) to the axle housing. The inner section is supposed to fit tight around the axle shaft, its got a little round spring in there to keep it tight (spring wraps around the axle shaft with seal under it).
Is that what you mean by inner seal? . Some 9" setups use a ball bearing, not a tapered roller bearing (which is what you have), and in your case, the bearing does not it self seal in the lube, and there is no inner seal. Your are correct the Timken (or like type) tapered roller bearing has a steel shell that fits on the axle prior to the bearing or lock ring. The outer edge of that shell has a rubber lip that snaps in place on the outer race, and also provides sealing between the axle housing and seal body. On the inside of the seal body (the steel shell) you have the rubber seal which rides against the axle shaft. The housing ends do not wear, as there are no moving parts.. But they could become distorted causing a leak, or the more likely problem is dirt, old seal material, silicone in the housing end at the seal surface area,,, This to will cause a leak and is why the outer edge of the seal often gets a light coat of RTV just prior to sliding the axle in the housing. If your leakage is occurring at the axle shaft / seal area. You have one of three problems. Damaged seal, worn or damaged seal surface on the shaft, or a manufacturing defect on the shaft. Maybe that shaft that was custom made was designed for the ball bearing design. Meaning, it should have a lube seal in the axle tube preventing lube from ever getting to the bearing, which is lubed by grease. If applications or pieces are inadvertently mixed up, you get a situation like you have... So there is another possibility for ya.

Figured it out!!!!
This is a 9 inch with disk brakes.
Currie sent the shafts with the bearings not pressed on.
For a disk break set up, the bearings require a spacer plate to space the seal out tight to the backing plate. Currie did not send that assuming the shop would re-use my old spacers. The shop did not.
So looking at my old shafts, I saw the difference, you need to have that spacer in there.
I spoke with Currie today and confirmed this.
So I'll have the shop press on a new bearing set with the spacers in there.

I blame Currie for this for basically making the assumption that the shop would know to use the spacer.

Wish I had a fawking garage and shop press, I coulda done this all myself.