I need a little help with some transmissions numbers:

the first is 914 / 11 HA 0039735...72 tail shifter?

the second is 914 / 11 / 10 HB 002163...??

spaces included for clarity.

Thanks

HB indicates a stock LSD. Tell me if the output flanges can turn independently. If they do not, you may have a nice expensive gear box there

HB indicates a stock LSD. Tell me if the output flanges can turn independently. If they do not, you may have a nice expensive gear box there

Ok where are the serial numbers located at? Both my trans have 914.301.302.00 I dont see anyother markings. Am I missing something?

The number is stamped on the bottom rib of the case.

The Cap'n

thank you cap'n

As Dr. Evil says, the "B" in the "HB" indicates it should have a relatively rare factory LSD ($$$) installed.

This has some info that might be helpful. Including example photos of different serial numbers....

http://www.roadglue.com/wiki/index.php?tit...14_transmission

I am the primary author of that wiki page and would love to have a photo of your serial number to add to that page. The format you give is not exactly what I would expect as I was not expecting to see the "10" before the "HB" part. But for the transmission in the 914-6, it used the "10" stamp to indicate 80% lockup LSD. So with the LSD being a relatively rare thing who knows if they stamped them consistently.

I also expected seven digits after the "HB". You only list six. Are you missing a digit somewhere? Assuming you are missing a digit at the end, that would put that in the range of the 1972 914/4 type 914/11 transmissions.

The Dr. and Richard Casto,

Here is a pic of the serial numbers and the case. I am not sure why this case was in with the others. I've also include a pic of a differential...the other question that I had was to do with the difference between a non LSD 914-6 and a 914-4. This diff in this pic is different from the other from the 914-4, IIRC. We seem to have dueling different differentials...doh. The flanges, also seem unlike the 914-4. (Looks like I am over the attachment limit...will add another post.

ThanksClick to view attachment

Serial number and caseClick to view attachmentClick to view attachment

How about a pic of the other side of the diff?

The other side:

Not other side o case, other side of the differential

AAAAh...

That is not an LSD, but it is also not a stock 914 differential. The out put flanges and diff are from a different box, I am not sure right off hand. It looks like someone clearanced the window on the side.

Dr. Évil et al....

In the shop where all these parts are stored, there are a lot of parts for 944's. So I checked the part number: 088 409 121 is for a 944 diff....mystery solved!

Any more thoughts on the case number?

Thanks for your help.

I was trying to read the part number on the diff, but couldn't quite make it out. Glad you figured it out. It looked like a Porsche diff, but I didn't know what it was.

Regarding the case number, what I say below is total speculation...

For the type "914/01" transmission (used in the 914/6), when it had an LSD installed, it included an extra "10" stamped. The standard open diff version of the 901/01 didn't have the "10". It's absence indicated an open diff. I believe that the "10" didn't just indicate that it used a LSD, but that it was an 80% lock LSD.

I think that that early Porsche LSD could be configured for other locking factors. And that while "10" = "80%" and that 80% was the standard value, there may have been other values that they might have delivered. Or if not delivered as stock, then could be done custom (such as on factory race cars?)

Now, for the type "914/11" (tailshift used in the 914/4), when it had an LSD installed, based upon the information I have seen, it has a "B" stamped in the second position. The standard open diff version of the 901/11 would have an "A" stamped in the second position. So you have "HA" and "HB". But there seems to be no indicator of locking factor for the LSD.

My guess is that maybe when they installed a LSD in the 901/11 that they may have sometimes? always? also included a code to indicate the locking factor.

Now, on the type "901/12" (later side shift used in the 914/4) they used an even slightly different serial number pattern. They still used the "HA" vs. "HB" to indicate open vs. LSD, but on the 914 Wiki page I linked to earlier, you can see a photo of a type 914/12 that indicates it has a LSD, but there is no other stamping to indicate something such as a locking factor.

So in short, my speculation is that the case you had originally had a factory LSD. That it may have been the common/standard unit with an 80% lockup factor and that whoever stamped it that day included the "10" to indicate the lockup factor.

But then again, I might be totally wrong.

Regardless, I was curious to see the photo as the best we can do is to look for a number of examples today and see how they were stamped by the factory.

Richard,

Thank you for your eloquent explanation. Not sure what I will do with the case. As I mentioned, for all of the parts in this shop, this case seemed a little out of place. With the name of the former shop's owner on the case and the fact that he completely restored a /6, number 1810, IIRC, he may have used the diff in that rebuild to keep all of the matching numbers in place...but as you said above , I could be totally wrong too

For historical purposes, would you be interested in the case?

I am, but unfortunatley I am not really in a position right now to buy it and ship it across the country.

The problem today is that when 914 owners have an issue with their transmission, sometimes the problem is serious enough that it is cheaper to just buy another core transmission and rebuild it vs. fix their current transmission. On top of that, there is the process of harvesting parts from core transmission for used, but still usable consumable such as bearings, sliders, syncro hubs, syncro rings, unusual gears, LSD, etc.). The left over bits which don't seem to wear out much such as the case, diff, pinion shaft, common gears, etc. sometimes get thrown away. Either they are too bulky or heavy to store (case and differential) or there is not enough demand for used parts to mess with keeping them.

However at some point the supply of rebuildable core transmissions is going to dry up. There are only so many of them. At that point, transmissions that were harvested for consumable parts and then were trashed would now be good starting points for rebuilds. My point is that I hate to see good cases and other parts thrown away. Not that you are saying you will toss that case, but if I can't take it, find a good home for it.

Hell, maybe there is a market to sell it to someone with the name of "BRENT"?

I'll call all my friends named Brent (all 1) to see if he is interested.

Its basically useless until the end of time Rich described is upon us. Until then, it is only valuable to someone who can store it. I would be surprised if George at AA would not want it and would buy it off of you.