901/911 tranny

[SLCooper]

Three years ago on the basis of pelican website testimonials I replaced my transmission lubricant with Swepco 201 in my '71 911T. My transmission, a 901/911, is the original transmission installed by the Porsche factory. Over the course of two years, a severe gear clash developed when upshifting from 1st to 2nd gear. As the transmission was 40 years old, I assumed it was time for a transmission rebuild. To get ready for transmission rebuild task, I reread Mike Caterino's "transmission refurb" link several times. In addition to purchasing a well worn 901/911 tranny for practice disassembly and reassembly, I also bought the special tools required to tackle this job. One of our local Buffalo experts suggested I replace the Swepco lubricant with Kendall NS-MP fluid. After draining the old lubricant and replacing with Kendall, purchased from our host, I drove the car about 200 miles and again drained the transmission lubricant and replaced with another 2.5 quarts of Kendall 80W-90 fluid. Unbelievably, the gear clash from 1st to 2nd is completely gone. As a matter of fact, the downshift from 2nd to 1st is now possible without coming to a full stop. My 40-year old transmission does not need a "refurb." My lesson learned is to stick with the Porsche factory recommendations.

[RWebb]

what do you mean by " Porsche factory recommendations"?

[Peter Zimmermann]

It's a really long thread, but if you have some time...

Swepco Transmission Fluid Question

[mspirito]

Is it really necessary to refill with Kendall 2x after the swepco? I have changed to swepco and it seems better in the first to second shift!

[john walker's workshop]

you won't get it 100% out with the first flush. in my humble opinion, swepco is great for gear face protection and not very good for balk ring (friction) syncro operation. too much slippage allowed between shift sleeve and the syncro ring that the sleeve is trying to slow down for a syncronized shift. this leads to the friction surface of the syncro being worn smooth and slick, reducing the friction function. as long as the syncro is being slipped upon by the shift sleeve, the brake bands inside the syncro ring won't relax to allow the sleeve to pass over the syncro and engage the dog teeth on the gear.

[RWebb]

interesting, John - thx

[neilca]

I have killed two first gear dog rings and a fourth gear using Redlines MTL in the race car. I think the Mtl, like the Swepco may be too slippery for the synchos.

Its funny, I tried synthetic oil in the engine. It didn't like that, had to go back to good ole 20w50 dino. These cas don't like anything new.