Porsche 911 Pinion Shaft and Ring Gear Question

Are the pinion shaft and ring gear for a '70 911T 911.01 5-speed the same as used in the 914 transmissions? According to the 911 and 914 PET catalogs the part numbers are the same: 901.302.901.02.

My 70 911 needs a new pinion shaft/ring gear and have been offered a matching 914 pinion shaft and ring gear in excellent condition. I'm just not sure they are exactly the same. Input is appreciated.

Happy Thanksgiving.


Dennis

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Originally Posted by denniso

Are the pinion shaft and ring gear for a '70 911T 911.01 5-speed the same as used in the 914 transmissions?

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Dennis, they're essentially the same. A 914 ring & pinion can be used in any 911 or 912 transmission up through 71, except for Sportos.

The 914/4 sets were manufactured by Volkswagen, while the 914/6, 911 and 912 sets were manufactured by Getrag or Hurth.
The setting codes changed for 1970, so the installer needs to be aware of the pinion code differences in this era.
The 914/4 sets have a slightly lower level of finish, but in my experience this hasn't been an issue. Even so, a 914/4 set should be priced lower than a Getrag or Hurth set in similar condition.

Jon B.
Vista, CA

I never pulled apart a 914 transaxle but I'm going to guess they flipped the diff due to the transaxle being behind the engine. This leads me to conclude that the primary wear surfaces of the ring and pinion should be opposite a 911. This should give you fresh wear surfaces when installed on your 911/912.

andy

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Originally Posted by ajwans

...This leads me to conclude that the primary wear surfaces of the ring and pinion should be opposite a 911...

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Andy, in either situation the primary load and wear surfaces are the same.
The pinion gears rotate and drive in the same direction, regardless of how the ring gears or transmissions are positioned.

Jon B.
Vista, CA

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Jon, Ajwans,

Thanks for the help.

I didn't realize the setting codes were different. I also didn't realize that VW manufactured the 914/4 R&P.

I can get a '75 914/4 R&P from a low mileage 914 that looks beautiful. The pinion gear of my 70 911.01 transmission is damaged (wear marks), so it needs to be replaced. I can get the 914 R&P for < $100, and I doubt I could get a nice 911 R&P for that amount.

I have the Porsche/VW pinion gear depth setting tool, so I'll be giving this a go myself.

So would you recommend this approach to one of your customers, or would you recommend they find a Getrag or Hurth R&P?

Thanks,
Dennis

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Originally Posted by Jon B

Andy, in either situation the primary load and wear surfaces are the same.
The pinion gears rotate and drive in the same direction, regardless of how the ring gears or transmissions are positioned.

Jon B.
Vista, CA

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Of course you are right, I am a dummy.

andy

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Originally Posted by ajwans

...I am a dummy.

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Well, you're wrong about that too ;-)

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Originally Posted by denniso

...I also didn't realize that VW manufactured the 914/4 R&P.

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Dennis, here's a Getrag 901 pinion shaft (top) and a VW-manufactured 914/4 pinion shaft (bottom) for comparison.
The manufacturer's trademarks are stamped on the splines...

Attachment 508269

Attachment 508270

Jon B.
Vista, CA

Quote:

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Originally Posted by Jon B

The setting codes changed for 1970, so the installer needs to be aware of the pinion code differences in this era.

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Quote:

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Originally Posted by denniso

I didn't realize the setting codes were different.

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Dennis, this information is in the factory Technical Specifications booklet for 69-71 models, pages 64 and 65.

Jon B.
Vista, CA

Hi Jon,

Thanks for the pictures. They definitely help to identify the different pinion shafts. I don't have the factory Tech Specs booklet, but I do have the factory 911 workshop Manuals. Hopefully that will have the info.


Thanks for the help.

Dennis