2QuickS

I miss my 901 box in my old 67 911S & am wondering how available is a G31 box (924 Turbo).

Also, will that box install into a 944S with reasonable effort?

wildcat077

Take a look at Clark's Garage website , there's a good description of all the 944 gearboxes and their application, although Dimi is very knowledgeable
regarding all transmissions and might chime in !

2QuickS

Thanks! I did some more digging & found info regarding 1979/80 924 Turbo box is what I want along with torque tube.

V2Rocket

in those 931 cars the transmission is mounted on the rear suspension tube, not the body.

so you'd have to swap out your rear suspension tube.

torque tube is shorter but same bolt flange at the front, driveshaft might be ok?

no idea if the late style gas tank will clear a 931 box.

PF

I am pretty certain that you will not have any clearance issues since the 931 box is a very small little gem. It is also alot lighter than the Audi boxes of the 944/968.
Worth to know is that also the standard 924 could be ordered with the 5 speed dogleg Porsche box but not with the same internals as the 931 version which is very strong.
Replacement parts I think is getting hard to find but should share alot of parts with the 915 box from the 911.

2QuickS

Good news, thanks!

So, I need:

• 924 torque tube (Turbo or is standard tube OK?)
• 924 shifting linkage
• 924 torsion bar tube (will 944 trailing arms work on that?)
• G31 gearbox (1979/80 Turbo gearbox)

J1NX3D

you need a 924 turbo torque tube. the input shaft is 25mm vs 20mm for the 924.

t0mbo

Long story short I had a 1980 5 lug 931 in high school, and after awhile the G31 wouldn't hold first gear on it's own anymore. Because I was on a "budget" I ended up swapping the whole rear subframe including trans, brakes, and suspension from an early 944, and it swapped over fine. I totally get where you're coming from wanting the dogleg gearbox; it just feels way more "special". I believe my brother in law still has that complete subframe (with G31) plus the access to the 931 as a (now) parts car in Colorado Springs, and could probably get you what you need to swap it over if you felt like having the G31 rebuilt to fix first gear. I personally wouldn't go this route since rebuilding the gearbox could get pricy, but it would be a great time to swap in a LSD while you're at it. It's probably way more cost effective to just find a good G31 and piece it together. Let me know if you want his contact info and I'll PM you. No pressure.

2QuickS

Well then, I'm interested! I wasn't looking for an OEM Euro, fiberglass front & rear bumper set but they "appeared" & I got them. Perhaps this is the same sort of "find" for a drivetrain I can retro into my 944S.

t0mbo

Great! PM sent with his contact info.

Jaffar

I am currently going through this conversion but from an auto. You will need to change the clutch plate and spigot bearing to accept the smaller drive shaft or do as I will and use the larger drive shaft from the auto and shorten and re machine the gearbox end spline to suite the G31 coupling. This will also require new, larger bearings in the torque tube.

I am wondering where to get an original LSD.

2QuickS

Just sourced a 931 gearbox from a buddy! This is long term project but the toughest piece is now inbound.

black944 turbo

One other issue is that the speedometer on the late cars (pre-abs) is off the gearbox and the 931 and early 944 is a cable. You will have to figure out how to get a speedo signal.

2QuickS

Speedo...what is that? Swimwear?

My old 911 had a bad speedo for years.