Just pulled the rear end out of my 1962. It is a 4:11 posi Casting #3789812 Date code C242. I want to change the R&P to a 3:36 or 3:23. I cant seem to find the gear set that I want anywhere.... either the carrier will not place the 3:36 ring in the right place relative to the new pinion or the pinion to yoke spline numbers do not match what I currently am looking at (17 splines). Does anyone know the correct part numbers for a 3:36 gear set that will fit in my carrier using the 17 spline yoke? Any suggestions based on ACTUAL EXPERIENCE would be most appreciated as most sales reps I have spoken to either "think" or "are pretty sure" that their part will work (definate maybe). Need some definitive accurate info please.
Thanks in Advance

 

You can PM DZAuto on this forum (Tom Parsons)....if he don't know then nobody does...
He's pretty much the definition of "actual experience" !

 

Thanks Frankie...I'll PM him right now!

 

I am going to jump in here before Tom gives you his sermon from a higher level of intelligence LOL .

You can NOT simply bolt a 3.36 gear set to your 4.11 posi carrier.

Carriers USUALLY come in families based on ratio series.

For C1's :
The 4 series carriers will ONLY work with 4.11 4.56 etc gear sets.

The 3 series carriers are required for 3.08 , 3.36 , 3.55 , 3.70 or 3.73 gear sets (I am sure some know it all will be all over me "there never was a 3.73 ratio !" - there are and I have some !)

There were some special gears made (now discontinued and now forgotten by me due to irrelevance) that I believe allowed you to run 4.11's and possibly 3.70's on the opposite carrier (had to cover that as if I didn't someone else would LOL)

There are no 3.23 gears for C1's

I don't know if there are any new (aftermarket) 3.36 gears available.
But they are a pretty common ratio available used at swap meets etc - I regularily pass them up.
Correction : Tom (below) lists 3.36's from US Gear

Contact Tom Watt at Tom's Differential's in Idaho he will have the proper Posi carrier that you need and can probably supply the gear set to match.
TOM KNOWS HIS STUFF - I have dealt with him for approximately 25 years.
I do not have Tom's current phone number since he moved from California where I used to deal with him.
Just Google Tom's Differential's and you'll be able to find his contact info there - I recently did but misplaced the #.

THIS IS THE DEFINITIVE AND ACCURATE INFO you asked for BECAUSE I KNOW from actual experience .

Jerry

 

Tom's Differential's web site....and I also have heard good things about him. The web site is rather humorous but gets the job done: http://www.tomsdifferentials.com/

 

Just went through this on a '63 - nobody makes a replacement gearset in any ratio with 17 splines (they're all 31) which requires a new yoke (adds about $150 to the cost of the new gears). Don't know if it's the same situation for the earlier pumpkins but I'm sure Tom Parsons can tell you for sure.

 

I just bought the ring & pinion, Eaton posi and install kit from - http://www.jawsgear.com/

They had the best prices. I took my 4.11's out of my 60 and using Tom's tutorial, built a 3.70 posi unit out of a old 3rd member I had laying around.

It had 3.36 ring and pinion that are in perfect cond. Let me know if you're interested in the gears.

Jim

 

Thanks to all. I was aware of the "special" ring gears for "cross mounting" but I remember them only working one way, that is, to run a 4 series gear on a 3 series carrier. Richmond Gear also has a bunch of those "Special" ring gears for both ways but not for the early diffs.

 

No problem with the earlier style pumpkins.

Jim

 

Thank you for your contribution - didn't take to long as usual.

 

Just took a real close look at the diff and noticed that the ring gear is stamped C01 884411 37-9 and the posi carrier is stamped 22158X and 170^. Could this be a 3 series carrier with one of the trick 4 series gear sets. If I measure from the ring gear carrier mounting flange to the center of the spider pin it's 1.5 inches. ?????

 

YOU could be in luck here :

I just quickly checked a couple of early Posi units I have - which I assumed (hope) are 3 series and the dimension from the ring gear flange to the centers of the spider shafts was ~ 1 5/8".
DOUBLE CHECK YOUR MEASUREMENT THERE ?

BUT THE BIGGIE : I also had a quick check through some of my rear end catalogues and the in the US Gear / Strange catalogue found part number 01-884411 for the "trick" 4.11 gear set ( for use on a 3 series carrier) !

Sooo looks like all you MIGHT need is the 3.36 gear set !

 

Thanks Qik I think that I did Luck out on this one... my 1.5 inch measurement was a bit of guess work with the unit completely assembled and it probably is 5/8 and not 1/2 but it is definitely not less than 1/2 and it looks like that ring gear is listed in a couple of places as "4:11 THICK". Again many thanks to all...
Bill

 

You're welcome Bill,
Hopefully it will all come together for you.
Jerry