Leaking Internal Diff Seal - Tearing on installation.

Hi Guys,

I am looking for any advice or information regarding installing a CV axle seal on my 2017 TRD offroad.

Needle bearing started to fail and so was replaced with ECGS bushing.

Tried to drive the CV axle seal on and the rubber around the outside of the seal was pretty badly damaged during installation. I reinstalled the CV axle and to no one's surprise... it leaked badly.

I tried again for a second time to install a new seal and the same issue (rubber tore along mating surface). When I pulled the seal back out I noticed that oil was seeping through the diff at the bottom of the oil seal mounting location (see picture, location labeled: "seeping"). Can someone confirm this is normal?

Some steps I have taken:

Confirmed the correct part.
2'' pvc pipe used to drive seal in with rubber mallet.
OEM seals lubed with gear oil on install.



I understand that these are finnicky and leak if not driven to correct depth?

Is the reference for the correct depth the inner flange (IF) or the outer flange(OF)?

I live in the rust belt and the lip of the inner flange seems to be quite rough. Could I sand down this to clean the surface (not the inner wall but the corner of the lip where the seal is driven in) to reduce tearing or will this cause issues?

Any suggestions/guidance would be much appreciated

 

wow with that rust, I would leave any slow oil leak, and maybe even create more. You’re on pace to loose the frame and other hard parts before an oil leak kills something else.


I have never done this particular job on this truck, but if that rust is touching the seal on the way in,, yeah it's probably tearing it. Maybe one of the techs know better, but I would use a wire wheel, or something less aggressive first. You want to remove rust and not the aluminum underneath, or that may very well cause a leak too.

 

Absolutely get rid of that rust ring before driving a new seal in (and Fluid Film your truck ASAP!!) Coarse scotch brite or steel wool or lite sandpaper would all do the trick. Its never going to be perfect, but you should knock the majority of it down best you can.

Depth looks ok from what I can tell. I think the issue is people typically drive them too deep.

Lastly, it would be normal to have a bit of gear oil spill out after taking the CV out. Thats the fill level of the diff. So I think that part is normal. Obviously any seeping or leaking once everything is fully reassembled is abnormal

 

I agree.
You are better off going close to flush, rather than deeper.
The deeper you drive the seal in, the more chances it will leak.

You need to clean the surface as good as you can.
600/800grit sand paper may be needed.

You could use a LIGHT coat of RTV around the seal.
It’s not ideal, but can work. The key here is light coat.
Take you finger and smear it on light around the outside of the seal.
Again, this is “the right way” to fix the problem.
But it beats pulling a CV over and over again.

 

Would cooling in the fridge not make the seal brittle?

I dont think its cracking. Its the rust forcing the paint off of the welds. In Canada they spray an adhesive salt solution on the roads during winter which inevitably ends up on everyones cars. Rust like this is pretty common. I fluid film twice a year. ​

 

So its seeping out from underneath where the base of the inner flange and the flat part meet. Ran my fingers around the inside and it seems that the bottom and top are not at the same displacement away from the housing. Not sure if its possible I knocked something loose when hammering this in???

 

Im not sure I follow that. But I would not refence the inside of the casting when setting depth, if thats what you are saying. Just use the outside like everyone is says. After getting rid of the rust ring

 

So I stopped by Toyota and a Transmission shop. They both seem to think that I have damaged the diff housing by displacing the internal flange. I guess seepage is not normal.

Both recommended rebuilding the diff...

Not sure what to do next.

 

You cant drive the seal all the way back or it will leak.

Use a toyota brand seal only, off brands have a hard rubber feel to them and the toyota ones are have a softer feel and less prone to leaking.

Smear a light coat of grease on the outside of the seal and on the inside of the seal as well. Coat the axle splines and smooth part of the axle were it makes contact with the seal with grease too.

The seal only gets driven back to be about flush with the outside side (Rust ring it sits next to) You don't need to clean that rust off unless its actually on the mating surface.

When you drive the seal in be careful to drive it in evenly, or use a small hammer to lightly tap the edge of the driver on the side of the seal that it is not going in as far.

Be mindfull of the small spring that is wrapped around the seal on the inside, dabbing some grease on it will help keep it in place during the install.

A coat of grease will help seal it up a little better. you could also try wet sanding the mating surface if there is any rough mating spots.