Jimjacqmx5

I recently lunched my motor hitting 1st at 150 odd km/h as the bastard gearbox wouldn't shift into 3rd from 2nd when giving it the berries on the track.. I had been experiencing very notchy shifting for a while and this was the end result. It was also very difficult to change down into 2nd from 3rd or 4th from high speed.
I have recently rebuilt my motor and I have also upgraded 2nd and 3rd to steel synchros.

My question is, what is the best gear oil to give me a smooth shift as it is still really notchy. I have ordered RS rear engine mounts as I believe this will help, especially on the track. My clutch etc is all less than 5000kms use and is a Sachs heavy duty upgrade kit. ie, clutch is all good. Linkage bushes etc are all in tip top shape.

It seemed from reading prior threads that MTR-1 gear oil is the go?

Who makes this, what is the exact name of the product and will it suit my tranny in everyway. ie, not have adverse effects on gears, remaining brass synchros etc.

Thanks....

crg53

Mobil Delvac 75-90 transmission oil is your best choice. It is not readily available in my area, so I need to order it in, do a search for your nearest dealer.

altarchsa

This is most often recommended on the 964 Forum, so far as I could determine: (no affiliation)

http://www.lufteknic.com/Merchant2/m...Category_Code=

(Delvac replaces the former Mobil SHC product)

I installed a temporary lube which resulted in notchy shifting, and have been very happy after replacing it with this. Several posts commented that some of the other GL-5 products were too slick, allowing the syncros to spin too fast, if I understand the technical aspect correctly. All I know for sure is this stuff works.

Jimjacqmx5

It is currently running Mobil 75-90.....

Streetfighter

You can use Swepco 201 as well. I know most will frown on it, but is good for G50 transmissions.

joey bagadonuts

Hey Brandon- I thought I read on Pelican that Swepco was the lube of choice for 915 transmissions--Red Line Synthetic 75w90 was preferred by G50 owners. Did you try the Swepco in your car?

FWIW, I have Royal Purple in my car. That's the brand my shop swears by and used in the box after installing steel syncrho's. After 7,000 mostly track miles, it still feels fantastic. I have a LWF, so can't really comment on the noise (which some people feel is a problem) but, as lubricants go, I can't imagine anything making it feel much better.

vernon

I would just like to say I have had Swepco in my 1989 964 for the last ten years. My shifting very nice I change it every two years on both front an back.Vernon

-nick

Gear oil change is coming up on my list too. I believe mine is still original at about 70k miles now and it feels like molasses in the cold.

I've seen some comments stating that Delvac can give notchy shifts and the normal Mobil 1 gear oil works better. Redline also appears to be a contender.

Ques: are there any different recommendations for C2 (open diff) vs C4 and C2 LSD's?

Streetfighter

Whats up Joe? It is a big misconception with Swepco being used only on a 915 gearbox. I have spoken with Porsche mechanics and they recommend using Swepco. They also mention not using Swepco in a 996 or later. I have Swepco and you drove my car, what did you think?

joey bagadonuts

Hey Man! Yeah, your gearbox was definitely cool. Not extra notchy or noisy--perfect!