914 transmission to 912

[derekfiveo]

I am looking for a 901 transmission (transaxle) and have found that there are a lot more 914 mid mount versions out there.

Is there a way to easily swap a 901 from a 914 to a rear engine configuration?

If so, would it be better to get a tail shift 901 from a 914?

Been trying to search but really have not found any real topics on this.


Thanks

[Walt Fricke]

Be careful you don't end up with 4 or 5 reverse gears, and one very low forward one.

[derekfiveo]

Originally Posted by Walt Fricke

Be careful you don't end up with 4 or 5 reverse gears, and one very low forward one.

Hence the question of. Can you swap a 914 901 trans to a rear engine configuration

[davekillen]

With the caveat that I haven't actually tested the transmission yet, I've done this.

You'll need a nose cone and shift rods (maybe not the rods if you use a tail shift trans?
not sure) from a rear-engine 901. You'll also need an m14 tap (if I remember right) to relocate the vent on top of the trans.

You then flip the ring gear when you rebuild the trans (this is what gives you five forward speeds).

If you decide to try it, or just want to rebuild a 901, I highly recommend the "Dr. Evil" dvds well known on the 914 forums... you can reach him at mike95125@yahoo.com

hope this helps! It's a fun project but like I said, I haven't actually run the trans I did this to yet, so YMMV.

[Mark Henry]

^^ agree, You can... but...nothing is simple.

You have to flip the diff, special measuring tool for this job and the knowledge to set it up correctly, I have a repop of this tool, but Dr Evil has the OE tool. The diff has to be a matched set.

For a early 912 and 911 there's some funky differences with the early 901 diffs and how the mainshaft bearing plates work, so care must be taken when mixing and matching parts.

Personally not the project for a newbie, I'd just ship the trans to DrEvil.

[Walt Fricke]

Am I correct that a flipped diff makes setting some of the various diff values a PITA? Normally you can, without any special ado, pull the side plate and pull the diff and attached ring gear out when playing with shims to get preload and lash within spec. But with the ring gear on the other side of the pinion gear, you also need to remove the pinion gear first?

[Mark Henry]

The tools to set the pinion depth are in this thread.

http://forums.pelicanparts.com/porsche-911-technical-forum/441403-ring-pinion-tool-p357a-questions.html

[derekfiveo]

If I could get a 901 case from a 912 and a 914 transaxle would flipping the ring gear and putting it all in the 901 be easier than putting new nose cone on 914?

[Richey]

I don't know the condition of things or your abilities , but installing a different nose cone and selector shafts should be much easier .

[stownsen914]

If you swap all the internals to a different case, you have to do the pinion depth setup to do it correctly. The tool is expensive, or have a shop do it.

If you flip the differential (to get the correct drive direction), no need to do pinion depth but you'd need to reset the ring gear backlash. This is easier to do DIY, you need a dial indicator and have to make up some simple tools/adapters. Not a bad idea to check the preload too which relatively easy. And then the nose cone.

Note that this wouldn't work out for a 70-71 911 trans since it has a different clutch arrangement.

[mepstein]

Chances are that any 914 trans you find will still need to be rebuilt - dog teeth, sliders and usually first gear.

[gled49]

ALU and Mag case parts are not interchangeable. U cannot put an Alu shift cover on a Mag main case. Internals are except clamp plate and main shift rod.