I'm getting really frustrated with this now. I keep leaking transfer case oil from the derby cover. I tried the gasket when they quit providing the O ring but that made my leak far worse. Then after I had to do a tear down of my tranny which involved taking off the transfer case and all I was good for over a year then all of a sudden I have not been able to get a good seal. I did switch to synthetic for the transfer case after the rebuild since it was all new gaskets and everything but the derby cover remains tight and leak free. I am using O rings again because my local dealer went with an after market supply of them but after my run to Redding on labor day weekend I have not been able to stop it from leaking and it's pissing me off cause I have to keep refilling the transfer case and that oil is not cheap. Of course I only have a three bolt cover not the five and to go to a five is cost prohibitive. I don't want to use RTV becasue that is a pain to clean up and redo every time. Anyone have any thoughts?

 

I'd try the RTV at least once. If it fixs the problem, there won't be any 'clean up and redoing' necessary.

 

If by transfer case you are talking about the primary, then (IMO) there is no reason to use synthetic. Also IMO sometimes synthetic will leak where dino will not.
You could try an O-ring with a larger cross section. Check McMaster-Carr or other distributors.

 

Ok, so it's an Evo, right?

that would be your primary drive. I know what you mean by "transfer" but Primary is the correct term.

1. sure it's not your primary cover gasket?
recent dealer service had a gasket put in ( new style) which did not deal properly.
dealer solution "your primary is warped- replace it".

My solution: old style "paper" gasket which conforms to inconsistencies in the sealing surfaces. Has to get old style gasket at indy shop.

also use old style Primary Lube- it will better seal with the paper gasket ( swelling it to seal)- I think synth seeps right past.

no leak.

2.) or your drain plug, wrap with teflon pipe seal

3.) derby cover, I smear a light coat of RTV on the O ring. let dry to tacky and gently tighten evenly to spec.
No gaskets are used with the O ring.

4.) do all your fills of primary lube through the primary chain adjuster hole, and make sure that has a good gasket, not a source of leaks.

MK

 

Is the cover warped? (Lay it on a flat piece of steel to see if it 'rocks')

 

agreed.evo covers are real bad about warping. i would bet thats your problem. i bet i have 5 or 6 in my shop that were warped take offs.

head

 

I'll be the third one to say its warped. I change the fluids on a buddy of mines bike every year and its a 1988 model. I used to go through hell trying to keep the derby cover from leaking due to it being so warped. One year I finally just replaced the cover and no more leak.

 

ditto on warped cvr

 

I agree on the synthetic point. Synthetic is designed to find all those nooks and crannies that conventional oil may miss. The molecules in the synthetic are smaller so it will tend to leak more....not less.
I agree with the larger gaskets. Make sure the area is clean before applying the new gasket / ring. Under pressure, even a pin hole sized leak will look like a gusher.
Good luck.
Dwayne

 

The cover was the issue. Didn't even think about that. Took it off and looked at it first and it was really obvious. The bolts had been cranked down so hard over time that they area around each bolt hole was deeper than the rest. Got a new cover and decided to give the gasket a shot again with new washers for the bolts. Torqued it to the specks and it hasn't leaked a drop since. Thanks for all the input I hate it when I miss the obvious.