C4 auto hard shift to reverse

[DPM77]

I finally got around to installing a "new to me" neutral safety switch, and afterward ,was shifting into reverse to test the reverse lights, and there is an audible "clunk" and associated feeling throughout the truck. To be honest, that clunk may have always been there to some degree, and the only reason I am noticing now is that I was focused on it. It does seem stronger now. It is loud, almost a bang. It cannot be good for the truck, its very noticeable.

I did not move or do anything to the shift lever, just took the kickdown lever off as necessary to pull the old part and reinstall. I see that the shift lever arm has adjustablity, after the install of a new NSS is it necessary to adjust that shaft arm?

Or could this just be a U-joint failing....

Anyone else experience this with their c4?

dpm

 

[BwoncoHowie]

Don't worry it was nothing you did. Every C-4 I have seen that was healthy and working normally had a strong reverse engagement. They run full main line pressure in that gear range. Valve body reprogramming kits will also increase main line pressures above stock specs. If you have a sloppy u-joint, worn spider shafts, or loseness among the bearings & gears inside your Dana 20, this could amplify the clunk you are getting when you shift to reverse. If the idle speed is too fast, it will also contribute to the problem.

 

[DPM77]

Thanks Howie.

Glad to hear that, I know that the u-joints in the front axle need help, probably should do all of them.

Great thing is, for the first time since I bought Ernie in 1999, we have reverse lights!!!

It is an amazing thing how much satisfaction I can get from an hour of work on my EB. It makes my whole week.

dpm

 

[NC-Fordguy]

I second BroncoHowie. Every C-4 vehicle that I have ever had does that. My old 86 T-bird did not as it had the c-3 or c-5? Basically Ford put some sort of restrictor/governor on that tranny to stop the loud clunk

Ed