Last night in my G I had it in manual mode, which I rarely do, but I put it into first and floored it when suddenly (before I got to accelerate) the engine and transmission divorced each other. I pushed it to the nearest lot and put it into park.

Symptoms:
The transmission grinds slightly whenever I put it into park.
Every gear acts like neutral. Even in park the car will roll.
It smelled like burnt transmission
This is the first time for this issue. They were always happily married, never one audible fight between them.

I have yet to get it towed so I haven't checked for codes or anything yet. I will do that tonight but just from these symptoms does anyone have an idea what it could be?
Clutch, torque converter, shifter linkage, or just blown the whole trans? Seems expensive

 

I did a full diagnostic using my iCarsoft CR V2.0
I found no codes in the engine or transmission which says the car doesn't realize anything is wrong.
I went through every monitorable transmission data point and took these readings

Torque Converter Lockup Clutch
Speed difference of lockup clutch in Neutral: 30rpm
Speed difference of lockup clutch in Drive: 70rpm (Is this normal?)
Transmission oil temp in Neutral: 70-80’C or 158-176'F
Transmission oil temp in Drive: 20-22’C or 68-72'F (Are these normal temps, and why does it get colder in drive?)
Engine Speed in Neutral: 660
Engine Speed in Drive: 550
Transmission Output speed in Neutral: 0rpm
Transmission Output speed in Drive: 140rpm at idle, rises when I give it gas
On off ratio of torque converter lockup 0 1/255

Solenoid Valves (Unsure if any of this is useful/important)
Actual current of component Y3/6y2 (shift pressure control solenoid valve) in Neutral: 759mA
Actual current of component Y3/6y2 (shift pressure control solenoid valve) in Drive: 2mA
Pressure of component Y3/6y1 (modulating pressure control solenoid valve) in Neutral: 1000mbar
Pressure of component Y3/6y1 (modulating pressure control solenoid valve) in Drive: 1500mbar
Pressure of component Y3/6y2 (shift pressure control solenoid valve) in Neutral: 1745mbar
Pressure of component Y3/6y2 (shift pressure control solenoid valve) in Drive: 9700mbar
Set current of component Y3/6y2 (shift pressure control solenoid valve) in Neutral: 760mA
Set current of component Y3/6y2 (shift pressure control solenoid valve) in Drive: 0mA
Status of shift valves in Neutral: 3-4 (This made no sense to me)
Status of shift valves in Drive: Not present

When I put it into neutral, drive, or reverse, it tells me it is in the correct gear.
Transmission speed increases alongside engine speed. Is it possible the problem is with my driveshafts/axels then? I'll check that next time I can.

I have also took a video of the sound it makes when I put it into park. It is a very odd sound to me. No sound when going into or out of any other gear.

 

The shifter linkage, although a little loose, is operating correctly.
No visual damage to axels or differentials, although the transfer case is seeping oil

After starting the car and putting it in drive, I noticed that the main drive shaft and front drive shafts were spinning but the rear drive shaft was not. How can the front drive shaft be spinning with the front wheels stationary?

I now believe the issue must be related to the transfer case, rear axel, or differential. Huge relief compared to a transmission issue.

Related: I have had an ongoing issue with my differentials. All 3 differentials worked, then only the center worked, so last month I had the lines vacuumed and refilled and I got the center and rear to work but fronts did not.

 

I would for sure post over on the ClubG forum. A lot more technical knowledge over there for the G.

When you say the front drive shaft was spinning, is this with the tires on the ground or up in the air with no load? No load situations do weird things. Also, unless the transfer case/center is locked, you can't guarantee that both fronts and rears will drive.

There's a lot of troubleshooting tips for working through non-working lockers.

One of many threads:
https://clubgwagen.com/forum/viewtop...roubleshooting

 

Ok so I thought to check for that and figured out something interesting.

With the vehicle still on the ground and in neutral:
Spinning the main drive shaft by hand is easy, it spins freely, it also will spin the front drive shaft.
Spinning the front drive shaft has the same results as spinning the main.
However, spinning the rear drive shaft spins the front drive shaft and the wheels (but not the main drive shaft)

So, I started the car and turned on the center differential and it drove normally! If I attempted this earlier I could have saved the tow fee. The weird noise when putting it into park also disappeared.

My guess is the front axel and front drive shaft is disconnected for some reason, maybe the axel gears are ground down, so without any differential engaged, the front is getting all of the power. Only by engaging the center am I able to send power to the rears to drive. However, I imagine this means I am only getting 50% power until I fix the front axel.

I am going to lift the car up and do a bit more troubleshooting and will report back.

 

Lifted the car up and tested everything again.
All differentials disengaged: Main drive shaft and front driveshaft spin, but not the wheels or rear driveshaft.
Center engaged: Rear left spins while the rear right nudges every few seconds (Right must have more friction for whatever reason. I wonder if I should look into this in the future)
Rear engaged: Both rears spin equally
Front will not engage (existing problem).

I have a solid front axle. The transfer case is clearly sending power to the front drive shaft. The front drive shaft and all visible u-joints are working fine. The problem must be within the front differential. I just replaced the fluid with Redline 75W90 back in February. I remembering checking inside and thinking the gears looked fine so I am a little shocked.
I wonder if it is possible that the front locker actuator somehow broke off and its pieces got imbedded in the gears, slowly grinding them away. Or the reason I could not actuate the locker was because it had nothing to press up against since the internal gears were worn down. Whatever the case, I need to disassemble the differential in the future.

I have found this PDF on the procedure but if anyone has done this before and can give some advice I would appreciate it.