Transmission identification question:D

Munky King · 02-25-2018, 05:09 PM

I’m still trying to work out exactly what my project mutt is / was and where it came from and the for sale ad for the other 74 case got

The owner that started working on it unfortunately passed away and his son didn’t know much about this particular car.

I’m new to 911s so equally clueless!
The car appears to be an early anniversary edition from 1975.
After a Pelican Search, I found this website 915 TRANSAXLE SPECIFICATIONS-GBOX Transmission
But I’m still a little confused (no change there!)

Is this a magnesium case? If so, what is the best cleaning fluid?
Which gear set / ring and pinion is it?
Thanks

Munky King · 02-25-2018, 05:10 PM

356911930 · 356911930's Garage

There is a large rectangular boss on the lowest p;oint of your trans about 3/4" x 3" it has your trans number on it with most of the info you will need. Post the number her for additional help.
Rahl

Munky King · 02-25-2018, 06:36 PM

Thanks. I'll go find it.
I thought the number above (9153011020R) was the right one! Just goes to show what I know!
Thanks again. I'll delve into the garage first thing tomorrow!

kevingross · 02-26-2018, 07:53 AM

Here's a photo of a 915 case and its serial number. The photo is from Pete Zimmerman's fantastic 915 rebuild tutorial.

Matt Monson · 02-26-2018, 08:45 AM

Sept of 1974. Mag case 1975 Model Year gearbox.

Munky King · 02-26-2018, 03:25 PM

Thanks Matt. Is that for mine or the one pictured above?
I had a quick look at mine and think it’s going to take a bit of careful cleaning to read the numbers. And with my old eyesight- I still might have to use a bright light!

Peter Zimmermann · 02-26-2018, 03:55 PM

Quote:

Originally Posted by Munky King

Thanks Matt. Is that for mine or the one pictured above?

Nah, 74D 4500 was taken from a 915 Tutorial that I wrote - make sure you check it out!

7 = Trans for 6 cyl engine
4 = 5-speed manual for USA/Japan
D = 1983
4500 = serial number (sequential build)

Peter Zimmermann · 02-26-2018, 04:11 PM

Porsche Wiki

Munky King · 02-26-2018, 04:18 PM

Thanks Peter (have book marked it for future reference!) and thanks Matt.

Thanks to Kevin and Rahul too! Now I know.

Peter, I'll be skimming your tutorial for cleaning tips for a mag case to start off with

Kester (Munky)

Matt Monson · 02-26-2018, 04:45 PM

Quote:

Originally Posted by Munky King

Thanks Matt. Is that for mine or the one pictured above?
I had a quick look at mine and think it’s going to take a bit of careful cleaning to read the numbers. And with my old eyesight- I still might have to use a bright light!

I'm going to go with 7152640
5spd 915 gearbox standard ratios.

djpateman · 02-27-2018, 06:25 AM

7152640 = 915/40 ratios 11:35, 18:33, 23:29, 26:26, 28:23 with R&P 8:31

Peter Zimmermann · 02-27-2018, 08:16 AM

Quote:

Originally Posted by Munky King

Peter, I'll be skimming your tutorial for cleaning tips for a mag case to start off with

Kester (Munky)

Hmmmm... I really didn't go into that. There are a wide variety of aerosol de-greasers available, and you can use a pressure washer as well. One note about pressure washers, be sure that you close off all paths for water to get into the trans, and to be safe (regarding rust) always take the unit apart after washing it (to guard against any water sitting on a still-good part and causing rust).

You can also visit O'Reilly's Auto Parts, or an AutoZone, and buy a parts brush along with aerosol de-greaser. The parts brush method is messy and hard to do, and time-consuming. Avoid using scrapers when possible or you might scratch the mag finish. Now, a really good way to clean a trans is using Safety Kleen, but that requires, I think, a contract for service intervals, and a basin large enough to hold an assembled trans.

Of course, you can always disassemble your trans dirty, and wash everything, including your tools, after it's apart. If you have a cleaning station such as Safety Kleen this can be a good way to work, but it can also be more tedious. Perhaps other readers will post their favorite cleaning method.

Munky King · 02-27-2018, 03:00 PM

Thanks everyone for the continued help and identification.

I think I will go the brush and degreaser route. I'm no where near brave enough to open it up. I'll leave that to the professionals and the talents mechanics like you all!

I'll be happy to clean it up and get it back in, in a working condition for now. I bought it as a project with the trans and engine out and what with missing parts and missing talent, that's a big enough challenge for now.