Gear noise, Type 1 vs. 901

[Bruce2]

One thing I have noticed with big engines and a Type 1 transmission, there is significant gear noise when decelerating in 3rd and 4th gear. I figure the noise isn't there with a stock engine because a stock engine doesn't develop enough compression braking like a big engine does.

What about a 901 5 speed?

Henry at Intermeccanica was telling me a few of his 901 5 speed cars made significant gear noise on deceleration in the upper gears. A friend of mine who owns a 70 911S said his gearbox is very quiet, not like his big engine'd VWs were.

For you guys with a 901 gearbox that is rubber mounted, do you hear significant gear noise on decel?

[Bruce2]

Isn't there anyone on this board that has a 901 5 speed?

[70Ghia]

Bruce2,
I have one built by Martin, he's the tranny guy here who offers the parts for the 901.
Its been totaly rebuilt and I use stock rubber mounts. This tranny is great, had it out the other day to try the new shifter that I got from him and I didnt hear a thing.

[Sandeep]

I have a 901 in my bug but can't comment on the gear noise on decelleration as I have not noticed it. I sounds normal to me, but my car has a gutted interior with door panels and carpeting only.

Sandeep

[Twystd1]

I have been working on and driving 914s for some years.

The only time I heard the R&P sing in decel or accel mode was when the R&P was not shimmed correctly. This rarely happens on a NON REBUILT 901.

It usually happens AFTER someone has rebuilt the 901 and didn't know how, or didn't have the right pinion setting tool and gasket thickness setup to preload the 901 R&P correctly.

Therefore after a short period of time, they start to sing in decel mode then later, in accel mode.

Sometimes the noise happens a few miles after rebuild. Sometimes after 5K miles or more.

If by chance this is the case. The R&P is a throw away item. Because the incorrect gear mesh is now imprinted on the gears and typically they will never mesh correctly even if setup by a pro. They will start to sing again prematurely.

By the way. In the U.S.
"IF" you could find a used factory 901 R&P setup tool.

It would cost ya about ten thousand dollars USD last time I checked.

I only know of two guys that have the Porsche factory transaxle tool kit for the 901.

The noise could also be coming out of the intermediate plate bearings.

Either one of those would be my first guess.

You may want to go over to www.914club.com and look in the http://www.914club.com/bbs2/index.php?showforum=2 forums and ask the same question (register first. It's free.) (If asked for a car vin # Just make one up. We don't care)

There's a fella over there named Dr.Evil that will have the answer for ya. You can PM him if needed.
Also look for Brad Roberts and Capt Krusty. All three of these men will also be able to answer you better than I as they both have more experiance than I on the 901. I have only rebuilt a couple of them.

Tell em Clayton sent ya over to say hello and check in with them.

The above is just my experiance. Yours may be differant.

Regards,
Clayton

[Steve C]

Hi

On a stock type 1 trans I used to get the over run noise when I used a solid centre clutch plate, when I went to sprung centre one it went away.

Steve

[Bruce2]

Is a 901 R&P a spiral bevel gear set or a hypoid offset gear set?

Interesting observation Steve. I never use solid center discs, and always get the gear noise. Even with gearboxes where the R&P was setup by VW.