Another 915 question
 

My gearbox in my 85 Carrera is the same as many here. All shifts go into gear just fine except 1st. Best to come to a complete stop, wait a bit, then goes right in. My question is this.....While I am waiting at stop for engine and trans to slow down to put into gear, is there a gear oil additive I can add to thicken up the lube to help slow the gears down a bit faster? I have new Swepco in the box but a mechanic told me he heard of folks putting in an additive to slow things down faster. I would think that I could shift into 1st quicker. I do all the tricks, double clutch, wait for RPM's to catch up, All that stuff. What do you think? Thank you very much, Nick in San Diego.

A very worthwhile read...

http://forums.pelicanparts.com/porsche-911-technical-forum/524583-swepco-transmission-fluid-question.html?highlight=swepco+oil

Hey
 

Peter, there are 5000 posts on that thread! Could you just tell me what would be a good additive for my 915 to help slow it down while coming to a stop? I know you like Kendell but I have the Swepco in it now are it was not cheap. Thank you, Nick

Kendall is less expensive than syncro rings, dog teeth and sliders......:) Mine was the same, Kendall helped, but when I bent four valves at the track I went ahead and rebuilt the box, and added an LSD and sport clutch while I was there.

Start a little fund and put in $30 a week in it for the next two years so you can rebuild your box. You can do the clutch while you are in there. Better make that $40 a week.

kendall 80/90 vw/porsche gear oil usually improves shifting over swepco. swepco is certainly good for gear to gear contact, but it doesn't seem to work as well as kendall with the friction style syncro system in our cars. but in your case, the fact that you have to stop and wait to shift into 1st suggests that the syncro is worn.

I concur with John, it's highly likely that the damage has already been done. It's not recommended to use additives in gear oil, for the longest possible life from your trans you should drive the car like it wants to be driven. Never force a gear change, use your two-part shift technique, and don't exceed 4,000 revs in first gear. I had customers get many thousands of miles out of 915s with your problem, but remember that it might only take one bad shift to render first gear unusable.

Nick,
Having owned both a nearly new (then) 85 and my current old 76 with the 915 gear box, I have found both cars to be difficult to get into first gear. One way of easing into first gear from neutral, after a stop, is to gently pull the shifter toward second gear which seems to synchronize the gear box, giving easier entry to first gear. Pushing directly into first is often impossible yet, after a brief move toward second with gentle pressure, it then slips into first like it wants to go there. Let us know if this helps.
Al

Double clutch to match gear speeds. Reduces the effort provided by whats left of the synchro. Also, it's independent of gearbox fluid.

Sherwood

Thank you all very much. Great info. My car runs great and I can drive it pretty well. I had a 356 for 10 years that I could shift by pausing between gears with no problem. I have only had the car for four months and I am still learning the best ways to shift. The slight move to 2nd gear and then into first works much of the time as does double clutching. The good news is the car always starts so no electrical problems and I fixed the A/C ! Next...the clock! Nick I love this car. It is so dang pretty and sticks like glue.