Need help verifying ring & pinion failure
 

Hello everyone, I suspect the R&P went out on my early model. I've read some of the other posts about this but am not quite sure if i'm correct.

I have a N/A LSD 944. Also my daily driver for the last two years.

Recently on first take off (after sitting overnight or many hours) the car would sometimes buck as if i was launching it- though I obviously wasn't. This happened to me I think 3 or 4 times now in the last two years of driving- the last time that happened was last night right before I heard a loud bang and clunking while rolling in gear.
It was almost like the fuel pump wasn't getting enough pressure built in the rail right away. (my fuel pump/filter is about 4 months old)

So, I had it towed home and when to check it out this morning:
I lifted the rear off the ground and put it in first/reverse and the clutch was grabbing but wouldn't turn the wheels.

Turned the car off and pulled the TT coupler inspection plate and it was still intact. It wouldnt spin by hand in gear either so I believe I ruled out the clutch. My clutch and all associated parts have less than 30K on it as well. New clutch master/slave as well.

Spun the real wheels and they both clunk when spun forward or backwords. I seriously doubt both my CV axles went out simultaneously. Niether axles have any play or damage or leaks. My wheel bearings have 7k miles on them and no noise either.

After spinning the wheels by hand I tried one more time putting the car in first while still on jack stands, the wheels then started to spin but with loud clunking as they spun.

No prior weird noises or grinds- still doesn't grind now, only clunks when in gear. Rolls quietly in neutral.

What I have NOT done yet is pulled the inspection plate or drained the fluid, because I'm being a bit lazy about it.

I do have an extra QM 5 speed sitting in the garage that i can throw in, but am unsure of its condition.
If the transaxle i have in the car is bad, which would be better: to have the current rebuilt, or R&R with my extra?

To me that sounds like a failed R&P- or something else in the transaxle...What you guys think? Help me verify this- I'm not really experienced with transmissions.
Any input appreciated.

Make sure that it isn't one of your inner CV joints that has separated. I had that happen with an aftermarket CV axle I had used to replace mine, and it acted in a similar way to yours.

Jack up the back, start the car and put it in gear. Look under the car and see if the output flanges on your transaxle are spinning, but the axle/tire isn't.

If that isn't happening, then it is likely your ring and pinon.

I'll second the CV joint issue. They will pop and jump just like you've experienced when going bad.

Sorry to respond so late...between work and the weather here in OR, I haven't had much time to work on my 944.
Last weekend I did finally do some diagnosing and my results where not as great as I had hoped.
One cv axle did internally grenade itself, but I do believe the R&P died as well.
I disconnected the axles and ran the car while on stands. While in neutral and all gears, there is a repetitive clunking sound that comes from the transaxle.
It even locks up momentarily sometimes while in gear...
Is that only R&P failure, or does that sound like more issues to anyone here?

Sounds like R&P.

Time to pull the gearbox and let Dr. Pain get to your wallet. If you are changing the RP for a used one,,, look for a 4:11 rp, expensive but puts a huge grin on your face.