Help Wanted - C4 guru

Jeffncs

Jeffncs

Well-Known Member
Joined
Apr 4, 2017
Location
Wake Forest
Looking for some tech help with the c4 in my 77 Bronco. Home rebuild (2nd one). Can’t seem to get the pawl to engage when drivetrain connected.

Works perfectly either way the t-case off. Stops working when drivetrain assembled. True for when connected to linkage and manually pushing the trans shift arm into Park.

I have video of it acting weird from a scope through the pan.

Thanks for advice!
 
Stupid question but your transfer case is not in neutral is it? The linkage compresses the spring on that parking pawl toggle ramp so that when the parking gear rotates to a spot that allows the pawl to fall in then it snaps into place. Are you saying that the gear still turns and the pawl is stuck and does not drop?
 
OnlyOneDR said:
Stupid question but your transfer case is not in neutral is it? The linkage compresses the spring on that parking pawl toggle ramp so that when the parking gear rotates to a spot that allows the pawl to fall in then it snaps into place. Are you saying that the gear still turns and the pawl is stuck and does not drop?
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Good though but the T-case not in neutral. When the full drivetrain is in place, I can roll the truck back-forth while holding the linkage in Park and replicate the clicking. My hypothesis is that the pawl or gear is worn allowing the pawl to hop out of the gear drops.

With the t-case out, spinning the output by hand, the pawl drops and locks. I can’t replicate it when spinning by hand.

My theory is that the pawl or gear have worn corners allowing the pawl to jump when there’s enough pressure (assembled truck rolling / manually spinning the wheels while on jack stands) and that turning the output by hand doesn’t have enough pressure to truly test the pawl engagement.

I have a new pawl coming later this week and will closely assess the pawl gear vs a spare I have set aside from another used trans.

Back-forth with the t-case is a lot of work laying on my back. Taking a toll on my body and patience.

Thanks for ideas!
 
Driveshaft connected. Pawl seems to hop out of the recesses as the back tire is spun. .

 
Use a new spring on that new pawl as well, but unless that thing is severely worn out should be pretty difficult to pop it out. It makes me think that the ramp is not pushing the pawl far enough when it does try to lock down.
 
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