C1 Differential

[John L.]

I have a 4.11:1 posi differential. There is a spacer between the ring gear and carrier. I want to change the ring and pinion to 3.55:1. Can I do it without changing the carrier?

[Dennis C.]

Yeah, Lose the 1/4" spacer... *NM*

[John L.]

Re: Yeah, Lose the 1/4" spacer...

Thanks Dennis

[Dennis C.]

John, What you likely have is a...

..."3 series" carrier. At some point in time, someone wanted a "4 series" gear set (4.11-1), so they added the spacer to make it fit without changing the carrier. In essense, what you are doing by losing the spacer and going to a 3.55 gear set is going back to the OEM setup. If you're going to spend much time on the freeways, I'd think about a 3.08. Just food for thought. Do what you will and enjoy your car. Best, Dennis

[Bill B.]

If you went from 3 to 4 series...

would you ever have to remove some of the carrier internal gusset(s)to make sure the ring gear cleared "all" too? Maybe this is when you go from 3-series to 4-series or it might apply in subject situation? I thought I read something once upon a time as I may be doing the reverse series conversion. But, I don't recall where I read about this.

[Bob Simard]

Caution

Check the clearance between the axle shaft ends and the spider gear shafts with the new ratio. Going from a 3.70 to a 3.08 can cause the axle to hit the spider gear shafts and destroy the posi plates and be a real pain to find out what is wrong. Don't ask how I know. I had to shorten the drivers side axle shaft about one-quarter inch.