After J30 install issue.

[cracka400]

I recently installed my j30 differential into my 98 240sx. Everything went smooth until I found out the driveshaft was too long. It burnt the seal out of the back side of the trans and threw some gear oil on the test pipe and in the transmission well. I took the shaft to a machine shop and had them take a half inch out and balance it. Came back home, cleaned everything by the exhaust, around the transmission, and replace the burnt seal with a new Federal Seal. Installation went perfect the second time around, but now there is a pure awful burnt gear oil smell that comes and goes. The faster you go the less the smell and the stench increases with the windows down. There is not a drop of gear oil on the underside of my car or any leaks for that matter. I cant figure out what is going on. Black Ice air fresheners and Febreze won't mask the smell. Any thoughts on what could be causing this are greatly welcomed. Please help me get the car not to stink lol.

[mixeds14]

have u check the transmission oil, if u leak a lot theres a possability that ur burning up the transmission.. also check the diff. oil... n sometimes the oil on ur exhaust will burn for a bit if u dint cleaned it good..

[OutToWinPAHC]

Spary it all down with some purple power. Any chance of the DS rubbing an exhaust hanger?

[cracka400]

I will check the oil in the trans, but I don't believe that i lost enough to cause that kind of issue. Mostly, it spun the grease from the seal and whatever was in the tail-shaft out on the exhaust. OutToWinPAHC, I used Awesome to clean everything up down there to the point you could eat off the bottom of my car lol. When the issue happened, smoke came from the shifter hole and around into the car from the oil burning on the exhaust. None of the material smells too bad of the burning. Also, I drove through the rain yesterday and tried to hit every puddle but the smell still remained.

[OutToWinPAHC]

Any chance of rear main seal or transmission front seal leak?

[cracka400]

When I had the trans off before I changed all of that stuff. There was a lot of tension on the transmission and driveshaft. It had enough pressure to cut into the end of the trans tail. I drove it just about an hour ago, and down all these back roads going about 60 mph I never smelled it once. Slowed down and down shifted to hit another road and the smell came back. It's just so weird. Also there is no noise what so ever coming from the trans and it shifts perfect.

[OutToWinPAHC]

It's not over filled is it?

[cracka400]

I highly doubt it. This smell did not start until the driveshaft issue. Also, I didn't have to add any fluid being as I didn't loose any while taking out and installing the driveshaft. I am going to go put it up on stands right now and see how the fluid is. Oh, and I made sure the diff was level and i put 1.5 quarts in it also. Fluid just started coming out of the hole so I don't believe that is the issue either.

[cracka400]

Ok, I went out there and checked the gear oil. It was a bit low and seems quite thin. Also, the oil did smell sorta burnt like the smell that comes and goes. I am running Royal Purple 75 90w. My J30 Diff is running 80 90w being that was all the store had in stock. It just seems weird that it happened all of a sudden like that. Anyways, the gear oil is less than a year old but it definitely needs changed. What weight do you recommend? An 80 90w like the diff or higher? Also, do you think that there may be damage to the transmission. It shifts perfect and I hear no chattering.

[OutToWinPAHC]

MFGR spec only.... and only use GL-4 in the diff.... GL-5 hurts the brass bushings and pads.

[cracka400]

Ok, I changed out the gear oil with a 80 90w and all is well now. The smell is completely gone and the trans shifts so smooth now. It just seems so weird that the Royal Purple would break down that fast. I also ordered from Courtesy the lower boot that goes around the shifter to keep the smell out. Thanks for all of you help guys. Btw, OutToWinPAHC your car is amazing. I've followed your build for quite awhile now. Good luck with everything.