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Parking lock pawl is dragging - 1964 Dart w/904
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Author:  SpaceFrank [ Wed Nov 19, 2014 5:49 am ]
Post subject:  Parking lock pawl is dragging - 1964 Dart w/904
It seems the racecar has developed an interesting problem. I searched the forum to no avail; maybe my search terms are bad. When in motion (forward or reverse), the car makes a rapid, staccato, high-pitched ringing sound that increases with speed. Over about 5 MPH it's loud enough that I'm worried something's going to break. Pushing the parking lever down will still engage the park lock, but flipping the lever up appears to not fully disengage it. We jacked the car up on all four corners and put it in gear, which allowed me to verify that the noise is coming from the parking pawl in the transmission tailshaft. I also noticed that the locking bolt in the park lock housing was missing. It must have backed out and fallen off on the track.

I replaced the bolt and attempted to adjust the parking cable according to the procedure in the FSM, but it didn't change the noise. I then removed the park lock housing, disconnected the cable from the lever in the trans, and physically manipulated the lever which engages the parking pawl, and still no change. It appears that the pawl itself is jammed. I looped some safety wire around the pawl in an attempt to pull it away from the tail shaft, but I couldn't budge it any further than it was already moving.

Any idea how to fix this? It's not immediately apparent how to remove the pawl itself. I dropped the transmission cross-member in order to remove the bolt that goes through the parking pawl, but it appears that the pawl rides on a hollow shaft or bushing which that bolt goes through. I see two springs on this hollow shaft, one on either side of the pawl itself. I assume these are return springs which are supposed to disengage the lock when the parking lever is lifted.
Author:  SpaceFrank [ Wed Nov 19, 2014 7:21 am ]
Post subject: 
More thoughts: after doing a bit more digging, I've realized that the parking cable sheath lock is not just a regular bolt, but a special tapered pin. I'll have to track another one of these down, I guess.

Also, when we installed this transmission, I pulled the speedo gear from our old transmission and reinstalled it into the new one. The speedo gear that had been in the donor trans appeared to have all the teeth stripped off, and I did find bits of broken plastic in the trans pan. Is it possible that some of those broken gear teeth could have worked their way back into the park lock area? The noise is definitely metal on metal, but I'm thinking maybe one of those plastic bits could have jammed the pawl somehow.
Author:  Danarchy [ Wed Nov 19, 2014 2:57 pm ]
Post subject: 
Quote:
I'll have to track another one of these down, I guess.
Let me dig through the parts of the '64 I junked, and see if I have one. -Dan
Author:  SpaceFrank [ Wed Nov 19, 2014 3:10 pm ]
Post subject: 
Thanks! I appreciate it. If you can find the little end piece with coil spring and lock wire seen in this picture, I'd be interested in that as well.

Has anyone else had this problem before, and is there any way to remove and inspect the parking pawl/sprag with the transmission in the car? I couldn't find anything in the FSM about this.
Author:  Danarchy [ Wed Nov 19, 2014 7:20 pm ]
Post subject: 
Sorry Frank, couldn't find the bolt. I have the cylinder piece the cable goes into, but the springs are toast! I also have the cover.
Author:  SpaceFrank [ Tue May 05, 2015 8:01 am ]
Post subject: 
Just an update for anyone who has this problem in the future. This was our "backup" transmission from the parts car I bought, which I recently had a chance to work on after we re-installed the original drive train in the race car.

With the parking lock housing removed on a workbench, I was able to see some broken bits of plastic up next to the "parking gear" that the parking pawl engages. I removed the large output flange nut and pulled the tailshaft housing off to find these bits of broken speedo gear:

Image

I put everything back together, and the output shaft now rotates freely without noise.

Weird thing about this transmission: on the race car's 904, the parking pawl rides directly on the lowest tailshaft mounting bolt, which has a special widened section just for that purpose. On this transmission, it looks like a previous mechanic lost that bolt, as it's been replaced by a standard bolt of the same length. The parking pawl itself has a tube or bushing pressed into the case which the pawl rides on. It works just fine, but it can't be disassembled like normal.
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