Will not stay in park on a incline. Popping sound from trans - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jmillsUT28 · 01-26-2016, 10:37 AM

Restoring this 72 blazer and when I park on a incline with the front downhill it will not stay in park. This is a auto transmission. When it moves in park the gear selector at the steering wheel does not move but you do here a clicking noise from the trans. It does not do this when parked on a hill with the rear downhill. Just when the front is downhill.

The bushing on the shift linkage coming down from the steering column is a little worn but does not seem to be casing this problem.

Could this be a internal problem with the trans? Any other options?

Thanks for the help like always

Bigdav160 · 01-26-2016, 11:32 AM

It sounds like the parking paw int the transmission is worn. You should be able to determine this by removing the pan.

In this example the rod that moves the paw is damaged

jmillsUT28 · 01-26-2016, 11:33 AM

Perfect. Will take the pan off now and see what I can find. Any idea where I can buy that paw at?

Bigdav160 · 01-26-2016, 01:20 PM

The paw is difficult to replace. The shaft the paw pivots on is in a blind hole. The pivot shaft is installed/removed on the exterior of the case under a small freeze plug.

Removing the freeze plug and coaxing the shaft out is frustrating. I've only ever done two. There's also a return spring the has to be installed correctly.

jmillsUT28 · 01-26-2016, 01:48 PM

Here are some pictures. From what I can see and looking at a picture of a new pawl online that mine looks to be in good condition.

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Below are two other pictures. The parking lock bracket does look like it is warn down a little but is this enough to cause it to slip?

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jmillsUT28 · 01-26-2016, 06:27 PM

Update for anyone that might run into this problem. The pawl as in the picture has two machined areas in it from the factory. Might look worn but it is not. The bracket that I have shown in the second picture holds the pawl in place. As you see in this picture it is worn and missing some material. I cleaned the bracket and then welded new material then used a grinder to smooth it out. I also noticed that the area where the two bolt holes are were bent a little. I flatted this out.

Problem fixed. Will stay in pack on a include and not move.

01-26-2016, 10:37 AM	#1
jmillsUT28 Registered User Join Date: Sep 2015 Location: Johnson City TN Posts: 108	Will not stay in park on a incline. Popping sound from trans Restoring this 72 blazer and when I park on a incline with the front downhill it will not stay in park. This is a auto transmission. When it moves in park the gear selector at the steering wheel does not move but you do here a clicking noise from the trans. It does not do this when parked on a hill with the rear downhill. Just when the front is downhill. The bushing on the shift linkage coming down from the steering column is a little worn but does not seem to be casing this problem. Could this be a internal problem with the trans? Any other options? Thanks for the help like always

01-26-2016, 11:32 AM	#2
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Will not stay in park on a incline. Popping sound from trans It sounds like the parking paw int the transmission is worn. You should be able to determine this by removing the pan. In this example the rod that moves the paw is damaged __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

01-26-2016, 11:33 AM	#3
jmillsUT28 Registered User Join Date: Sep 2015 Location: Johnson City TN Posts: 108	Re: Will not stay in park on a incline. Popping sound from trans Perfect. Will take the pan off now and see what I can find. Any idea where I can buy that paw at?

01-26-2016, 01:20 PM	#4
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Will not stay in park on a incline. Popping sound from trans The paw is difficult to replace. The shaft the paw pivots on is in a blind hole. The pivot shaft is installed/removed on the exterior of the case under a small freeze plug. Removing the freeze plug and coaxing the shaft out is frustrating. I've only ever done two. There's also a return spring the has to be installed correctly. __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

01-26-2016, 01:48 PM	#5
jmillsUT28 Registered User Join Date: Sep 2015 Location: Johnson City TN Posts: 108	Re: Will not stay in park on a incline. Popping sound from trans Here are some pictures. From what I can see and looking at a picture of a new pawl online that mine looks to be in good condition. [IMG][/IMG] Below are two other pictures. The parking lock bracket does look like it is warn down a little but is this enough to cause it to slip? [IMG][/IMG] [IMG][/IMG]

01-26-2016, 06:27 PM	#6
jmillsUT28 Registered User Join Date: Sep 2015 Location: Johnson City TN Posts: 108	Re: Will not stay in park on a incline. Popping sound from trans Update for anyone that might run into this problem. The pawl as in the picture has two machined areas in it from the factory. Might look worn but it is not. The bracket that I have shown in the second picture holds the pawl in place. As you see in this picture it is worn and missing some material. I cleaned the bracket and then welded new material then used a grinder to smooth it out. I also noticed that the area where the two bolt holes are were bent a little. I flatted this out. Problem fixed. Will stay in pack on a include and not move.



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