Please help me out with transaxle application data.

[Zeke]

Here's the short question: Will a 66-67 901 fit my '71?

Here's the long version: I discovered a while back I had a tranny from a '64 911. See here. I found someone on the East Coast interested in the thing, so I shipped it. The deal was a trade for any 901 that would fit into my car. He has a 901 from a " '66-'67," (his words) and he wonders if I can use it. We already know that the drive flanges have the smaller bolt. I guess I will either have to switch over the ones from my present trans, or buy new CV's with the smaller holes.

But, the big question involves the operation of the clutch. My '71 is the last of the "push" types, right? My guy on the East Side is afraid that the 67 is not compatible. I thought it would be the same.

Help, please, and thanks.

[Early_S_Man]

Milt,

The '70 - '71 models were the first engines to use the 'pull-type' clutch pressure plate and 'flat' flywheel, ... not compatible with the '64 thru '69 transaxles. Your engine would have to have a 'cup-type' flywheel to utilize earlier the '64 transaxle, so you already may be setup to use the '66 - '67 transaxle.

[Zeke]

Thank you, Warren. However, I must have made myself unclear (again). The very early tranny I acquired came with a very early motor. allegedly the 125th 6 ever made. Foolishly, and due to lack of knowledge, I kept the tranny thinking I could use it. The first clue were the Nadella drive hubs, now that I know what to look for. It's never been in my car.

So, I contacted the fellow that got ol' no. 125 and said, "Guess what?" Now he has a full unit, motor and probably the tranny that came with it in '64.

Well, that's not good news. Seems like I need a two year only tranny. No wonder every one likes the 915 swap. I LIKE the 901 shift pattern.

[Grady Clay]

Milt,

You want a ’70-’71 911 transmission for the pull type clutch. He should trade you 3-4 of those, perhaps even throw in a ZF LSD for that original ’64 and be delighted about it.

Yes, I suppose you could make a 901 work but it will take lots of scrounging and way too much effort.

Best,
Grady

[Early_S_Man]

Milt,

Well, you could still fit a cup-type flywheel to your engine ... assuming the Nadella half-shaft problem has a solution. If the '66 - '67 transaxle has a ZF in it ... it might be worth the trouble! I have often wondered if the Nadella output flanges could be redrilled for the '69 - '75 4-bolt CV pattern???

[Zeke]

Funny that you say the 901/0 no. 131 111 is worth much. When I posted the info about it, not much was said. Everyone here had an opportunity to ask me about it and no one spoke a word. I had to hustle the deal myself and I'm happy that it found it's old friend again, the motor.

The fellow on the other end will do right. I have told him we can work things out in many, many ways.

But, now I have to decide very quickly whether to look for a good 2 year only tranny, rebuild what I have or just drive it another 1000 miles and hope for the best. It has a lot of slop in the R & P and makes a whine at certain speeds under light load crusing.

I'm going to Monterey at the end of the month, so this deal needs to be worked out in less than 2 weeks. Swapping in another trans is doable in the time frame. Rebuilding is iffy when I go to order parts after finding out what I need. I had ideas about building something a little different. Like my 901 in my 914 with the shorter 3rd and 4th. That was a lot of fun.

[jluetjen]

Zeke;
Finding a 911 box isn't that difficult. You could most likely get one for ~$150. I assume that the '64 was not being used in your '71S -- correct? Anyway, from where you are the options as I see them are...

1) Retrofit your clutch cable set-up and flywheel to the pre-'70 versions and use the 901.

2) Figure out if there are any gears from the 901 that you want to keep or swap. Then find the 911 box and combine the "best of gears" to get your ideal ratios. I'd check with John Walker, he seems to have a pretty good selection of 901/911 boxes and parts available.

Here's one that should have sold on ebay except for the buyer was holding out for too high of a reserve.

[Todd Simpson]

I tried this a few years ago and failed. The drive flanges were different and did not swap from the '67 trans to the '71. I knew the clutch would need to be changed but I never got that far.

I agree keep the 901 shift pattern, I'd be interested to hear if you cure the R&P howl. 2 different 911's in my car were noisy as hell, one even after a proper rebuild.

2.2S and a 901 is some good stuff.

[Grady Clay]

Milt,

John has good suggestions here.

Let’s go over 1) first. Unless you convert to the early (smaller) 215 mm clutch, you must reposition the clutch release bearing fork pivot. This is undesirable and expensive because you need to buy all new clutch parts, flywheel, flywheel bolts, etc. To maintain the 225 mm pull-type clutch you must reposition the pivot location on a 901. This requires setting up the main casting on a mill and drilling and inserting the pivot in the right place. You also must find a pair of ’69 only axle flanges. Yes, it can be done. No, you don’t want to go there if you can buy 911 transmissions for $150 each.

John’s 2) is the best way to go. Buy several 911 transmissions and several ’68-’69 donors for the gears. Pick all the best parts and add some new pieces where appropriate. Choose the gear ratios you want. A ’70-’71 geared as a ’68 (AFMSX) is great. With some searching you can locate the gears necessary for AFKQV. I’m sure JW can help you there.

With your skills you can easily build these transmissions yourself. It takes some specialized tools (mostly homemade) and a clean and organized place to work. The Forum can lead you through the process. You will be an expert in no time. The only exception in the initial setting of the ring & pinion gears and the differential preload. You should have someone with the tools, skill, and experience do that operation. You too can do it if you are willing to invest in the tools.

If you want to have track specific gearing, it is easy to swap gears between sessions. With practice, you and a helper can have the transmission out and apart in ½ hour or less. Allow ½ hour to re-gear and an hour to reinstall and double check everything. The key is practice and having all perfect hardware. You can have a spare, track specific transmission with a spool and geared for Willow or wherever.

Best,
Grady