Transfer case output shaft leak after switching to Redline

[parsky1]

I switched to redline 75w-90 for the diffs and transfer case. Rear output shaft started leaking at transfer case. I could also smell gear oil when I came to fast stops at lights. Replaced seal in transfer case and seal in companion flange both with oem parts. Old seal was very stiff. Seemed to fix it but now still have a bit of oil seeping out and can still catch a small hint of it when stopping. I swear a drop of this stuff will stink up your whole garage. Any thoughts? Should I just switch back to a cheap conventional oil?

 

[alia176]

syn oil are more "slippy" than conventional oil but I'm surprised why the leak is still present after replacing the seals with OEM seals. Wonder if something else is going on?

 

[parsky1]

syn oil are more "slippy" than conventional oil but I'm surprised why the leak is still present after replacing the seals with OEM seals. Wonder if something else is going on?

Well it’s either the breather or companion flange sealing surface is really worn. When I did the seal I noticed the breather hose was rotted off the transfer case actuator. I trimmed it and stuck it back on. It might have been to tight and pinched. Maybe pressurizing the transfer case? I bought a stainless 1/8” barbed union and 1/8” ID fuel line and made an extension tonight. We will see if that helps first. Otherwise new companion flange and new seals all over will be $200. I tried to blow through the breather tube. Felt like it kept taking air but when I let off it push out some nasty gear oil gas. Yuck That might be normal if the breather has inherent flow restriction?

 

[alia176]

Sounds like you're on the right track. Let us know how things work out.

 

[parsky1]

Sounds like you're on the right track. Let us know how things work out.

I bought a 1/4” stainless barbed union and band clamps off Amazon and picked up some 1/4” fuel like from the auto parts store. I made a short extension for the shortened original breather hose which took out the kink. It appears to no longer be leaking. I’m a little nervous that it only leaked out the rear output seal and not the front. Front is still original. So far so good and I don’t smell gear oil anymore when I stop.

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So far I’ve dropped $2500 into this thing this year with timing belt, radiator, hoses, driveline fluids, shaft seal, and transmission drain and fill. Just bought $500 worth of spark plugs, ignition coils and oil dipstick o-ring for my next project. After that I need to figure out a plan for leaky exhaust headers ($2-3k), new suspension ($2.2k) and tires ($1.5k). I keep telling myself it’s cheaper than a payment on a new 5th gen.

 

[parsky1]

Also, anyone doing the seal. Buy a 3/8” brass drift with an hammer and punch one side of the seal into the transfer case. This will spin the seal and it will come out. The YouTube videos show screw drivers but that is a royal pain. Also, don't screw around unstaking the 30mm bolt on the companion flange. Put a 30mm impact on it and give it the full beans. Throw it away and buy a new one.