930 hard to get in reverse tech tip.

[Ryan]

Hello gents,

Here is a small tech tip for those of you with Porshce 930 transaxles. One complaint I have heard with the 930 is the stiff reverse detent. It becomes hard to get the gearbox into reverse when using a cable/rod shift system other than the factory's short style linkage.

Follow these steps and you will find it much easier to select the reverse gear.

1st. Locate the reverse detent plug on the passenger side of an inverted 930, if your car is so equipped. If you don't have a 930, well your in the wrong thread.

2nd. Using a 17mm wrench/socket loosen the detent plug and remove it. It is spring loaded, so please be careful not to just let it fly across the room and bury itself behind your bench.

3rd. Remove the detent plug, spring and detent plunger.

4th. Measure 12mm from the end of the spring and trim the remaining off. you should be left with roughly 84mm of spring. DO NOT cut more than 12mm off of the spring, as the detent pressure really begins to drop after that point.

5th. Assemble the detent plunger and spring and insert it back into the detent hole.

6th. Reinstall the detent cap and tighten, tourqing once to 14-18 ft. lbs.

7th. Shift comfortably into reverse instead of bracing your foot on the dash and tackling the shifter into position.

8th. Apply liberal amounts of throttle at your discretion!

 

[Bill Musarra]

Since my 930 is in the shop getting the spray bars attached. I forwarded this thread to him for his thoughts. This is what he wrote back:

Good question, since neither the guy who wrote the thread, nor I know the mechanical advantage of your shifter arrangement. I can tell you that the reverse gear in that transmission is definitely the weak link. It is fabled to be made out of glass. If you crash shift reverse, it will break, and the debris can be rather damaging. The factory shifter has secondary springs on the shifter as well to make sure reverse gear is really what you want. As easy as it would be to modify in the car, my thoughts would be to wait and see how much effort there really is. If it turns out to be too much, changes can be made incrementally. Additionally, you might consider a secondary lock-out on the shifter. In that way you could reduce the spring tension without any real danger. Just my two cents.

Since I am putting in an experimental shifter/arrangement, I will have a wait and see. I will post the observations/measurements when it is installed in the next few weeks.

Bill

 

[Ryan]

That is correct, the 930 does have a weak reverse gear. It is not recomenderd to shift hard into reverse, and dump the clutch or jam the gas while in reverse. It is not a very wide gear and does not take a lot of torqe very well. I cannot comment on the shifter system you are using that is application specific, however when you cut the spring down the reverse detent tension is less. A reverse lockout on the shifter is a good idea in any performance application. If you shift into reverse at any speed going forward your car is not going to like it, that doesn't matter what your driving!!!