I don't know about this but we have changed out the spider gears in
our race car to accept the 32 tooth splined axles from the 28 tooth
splined axles... Maybe you could change out or swap the spiders in
yours and retain the original axles???
Rogerg
51-3100 Stocker
> From: "Kevin D. Pennell" <oletwuk@fastrus.com>
> To: "Steven & Sharlyn Rocha" <srocha@pacbell.net>,
> "Oletruck list" <oletrucks@autox.team.net>
> Subject: [oletrucks] RE:Changing the differential
> Date: Tue, 4 Jan 2000 18:48:55 -0500
> Reply-to: "Kevin D. Pennell" <oletwuk@fastrus.com>
> Steve,
>
> I'm in the same situation with my "38", though with a 3600 series, I think
> your gears would probably be 5.14:1, same as mine. No matter, they're still
> bad ju-ju for any speed at all. I have standing "yellow stickies" posted by
> the phones of about all the rear-end places in the USA to call me if a used
> set of 4-something ring and pinions magically appears in their shop. New is
> out of the question. Correspondence with every major manufacturer in the
> U.S. says "Sorry, you'll have to upgrade your differential." I think that a
> 3-something gear set is wishing upon a star, myself. Given my lack of luck,
> I've pursued alternative methods. See, I have a NAPCO 4x4 and I just CAN'T
> upgrade my front axle housing. I'd sooner shoot myself. (Front and rear
> diffs are identical, hence the importance of retaining the stock front and
> rear axle housings).
>
> Your question raises a "possible" solution that I've been presented with by
> a pretty knowledgeable fellow. I haven't done it yet as the bucks haven't
> appeared for this experimental portion of my project, but I intend to give
> it a try at some point in the future. Maybe someone on the list can shed
> some light on whether or not this has worked/will work for sure.
>
> Here is a "Proposed Solution" to the dilemma. I need "CONFIRMATION" or
> "MYTH DESTRUCTION" here listmembers. Little help, PLEASE?
>
> The TF series "Corporate 3/4 & 1-ton differential units have a smooth
> round 10-bolt inspection cover. I've been told that the differential itself
> is called a 10-1/4" drop out unit, getting it's name from the diameter of
> the ring gear. The "drop-out" unbolts and is removed from the front of the
> rear axle housing (and\or the rear of the front axle housing on my 4x4).
> The axles are 17 spline axles, and the model number for the GM Corporate
> axle is HO-72.
>
> A later model corporate 3/4 and 1-ton differential drop out unit,
> manufactured from the early 60's through the early 70's will directly bolt
> in to the early style TF axle housing, but is designed for 30 spline axles.
> The matching 30 spline axles from the same series differentials can be cut
> down 1/2 inch at the differential end, which then becomes a direct bolt up
> into our older housings.
>
> Possible benefits of this swap include a stronger axle (30 vs 17 spline),
> and the instant on the shelf, or in the junkyard availability of myriad ring
> and pinion combinations, including posi-traction units. In addition, the
> drop out assembly should have the backlash correctly set already, or can be
> set for a reasonable price by a rear end shop as it's already out of the
> truck. It then becomes an "owner can do" project, with the only really
> technical portion being proper torque specs on the install.
>
> I did ask an axle manufacturer about the strength portion, and he says
> that it's very true. 30 "is" stronger than 17.
>
> If this scenario is in fact true, then junkyards had better stand by for
> the crowds! What do you say "oletruckers"???
>
> Kevin P.
> '59 Apache 38/NAPCO
>
>
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
rogerg
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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