Redline 75W90NS Do I have a Problem???

Hi guys and gals
After reading many posts on the positive affects of using Redline 75W90NS, I put in the old 308. There was much improvement in the shifting especially from 1st to 2nd however, the thing started leaking like a sieve after long drives. I know the synthetic stuff is known to slither past the gaskets but I thought it was more of a problem in engine gaskets not the tranney because the oil is much thicker. Did anyone else experience this after changing to Redline??? If I go back to whatever was in the gear box will this leaking stop???

 

That did not happen on my 328GTS or current 355 spider.

 

Where is your leak coming from? Transmission oil leaks seem rare - although 308s/328s can leak from their "shift shaft seals," per my reading. This usually required replacement of the seals, and is fairly common (and not a huge deal).

 

I'm using that in my 348. No problems to date.

 

There are a number of places for trans oil leaks. Axle seals/driveshaft flange, o-rings at bell housing connection, transmission pan, etc. You could take out the redline, and replace with what was in there and see what happens. I would live with a small leak (until you can figure out where it leaks and fix it) fin exchange for the better shifting, if it was a dramatic change.

Do you have an idea where the leak(s) is? A big leak should be easy to find.

 

Sounds like simple overfill.

 

I stopped a fair amount of leaking on the studs (of both pans) by installing nylon centered lock nuts.

 

Thanks guys for the tips. I did see some leaking around the " Shift Shaft". A mechanic friend suggested acorn nuts to replace the pan nuts with some type of sealent added or maybe the nylon washers might help because there is oil on a lot of the pan nuts. I think for now I'll take the suggestion to wait and see because there is improvement in the shifting. As for an overfill...maybe but I used 5 qts and watched for the flow out the check plug. Thanks again.

 

* You used 5 quarts but was the car LEVEL when you checked for flow out the plug hole ? If the car was jacked up in the rear, it will hold MORE fluid than it should. (I almost made that mistake)

 

* You used 5 quarts but was the car LEVEL when you checked for flow out the plug hole ? If the car was jacked up in the rear, it will hold MORE fluid than it should. (I almost made that mistake)

 

Just worth mentioning...in a previous life I used to sell specialty industrial lubricants and one of our big concerns was the interaction between any seal and some of the additives in synthetic lubricants. These additives can cause seals to shrink, expand or degrade. Especially when the seals were previously exposed to a more conventional lubricant.

fwiw....haven't had an issue with my 328 since switching, except buttery 1st to 2nd shifts when cold

 

The car was jacked up when I add to oil but I measured the jack stands because I was concerned about the car being level. Are 5 qts the proper amount??? It took all 5 qts to get the oil to come out the check plug.

 

Mine took about 4 1/4 quarts.

 

5 ? ! thats too much. check the breather tube and see if its purging fluid. this stuff creeps when it gets warmed up, very little of it goes along way and gets on everything. i doubt you hurt anything though. open the trans pan fill plug, and you should just start to get a small stream of gear lube. thats when the diff and trans are full. 4-4 1/4 sounds right. i would have to look at my notebook in my shop to be sure.

 

Assuming you did not add more than 5 qts, your problem is probably nothing more than the seals are old and hard, the old oil over time has built up shellac on the rotating metal pieces near the seals keeping the old oil in. When you changed to Redline, it has a super good detergent which will dissolve these deposits and usually within a couple of days of driving the oil starts to leak out from the axle seals. Change the seals and you will be in good shape.

Some additional “Good” thing to do is at this point is change the shifter shaft seals, Shifter shaft boot, re-grease the CV joints, change the CV joint boots, and change the Axle bolts. These procedures can be done on your back on the floor, with the car jacked up 8 to 12” usually in a couple of days unless you encounter other problems.