55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

alden · 10-03-2010, 09:25 AM

Kindof a specific request. I searched for axle swap info but only came up with a lot of people going with 9" rears for their v8 conversions etc and AD truck info.

I want to get a better gear ratio and my current axle needs a rebuild either way, so I'm hoping to go junkyard hunting and find an axle that will give me the following:

Keep the 6 lug chevy pattern
Keep the same axle length
Keep the drum brakes
Be a direct swap or at least as minimal effort as required
A low 3:xx gear set

Does anything match this description? It's going to go on a 1959 3200 longbed fleetside with the stock 235 and 4 speed if that means anything.

Thanks!
Alden

Knothead · 10-03-2010, 01:06 PM

To retain the 6 lug wheel it will probably need to come out of a truck. I used one out of a 65-66 with a posi unit from the factory. I'm think they were available with Leaf Springs or Coil springs?

The Good Ratchet · 10-03-2010, 01:18 PM

I would look into S10 and S15 pick ups. Many of them run 3.73. The bolt pattern might even line up. Only way to tell is to run out to the junkyard...

raycow · 10-03-2010, 01:56 PM

You don't have a lot of choices if you are looking for a bolt-in. A 3.38 gear was optional in the 55-62 Chevy 1/2 ton rear, but very few trucks actually got ordered with them. Fortunately, 3.38 replacement gears are available from aftermarket vendors.
http://www.tomsdifferentials.com/catalog.asp?pg=15

GMC started using the Dana 44 toward the end of the TF years. If you can find a TF with one of these housings, it will be a bolt-in swap. Gear availability is much better than for the Chevy rear.
http://www.ringpinion.com/PartsList....ID=15&CatID=10

Because of the scarcity of the above two, most people just go with a 12 bolt and weld on leaf spring mounts. 63-69 (and some 70) are the same width as your stock rear and you can find them with 3.07 gears. 4WD trucks came with leaf springs, but I don't know if the spring spacing matches a TF. It couldn't hurt to measure one though.

Ray

**Wrenchbender Ret** · 10-03-2010, 05:27 PM

I've alway's heard that the older blazer rear ends are good candidates as they have the 6 bolt wheels. The S-10 4X4 are supposed to be good but they wood be a little light. I put a Firebird in my 58 but it has the 5 hole small pattern. It already had that pattern on the front from a disc brake kit.

magicoolbus · 10-03-2010, 08:09 PM

Patrick's Antique Cars and Trucks in Casa Grande AZ sells a 3.38 : 1 ring and pinon for around 200.
http://www.patricksantiquecars.com/chevyparts.htm

57 Jimmy · 10-08-2010, 03:22 PM

What is the normal gear ratio in this era trucks with a 4speed?

alden · 10-08-2010, 04:34 PM

Quote:

Originally Posted by 57 Jimmy

What is the normal gear ratio in this era trucks with a 4speed?

I've been told my truck has anywhere from a 3:93 to a 4:75 (numbers may be off by a few digits) I haven't gone out and measured yet.

57 Jimmy · 10-08-2010, 05:20 PM

Quote:

Originally Posted by alden

I've been told my truck has anywhere from a 3:93 to a 4:75 (numbers may be off by a few digits) I haven't gone out and measured yet.

Thanks

raycow · 10-08-2010, 10:36 PM

Quote:

Originally Posted by 57 Jimmy

What is the normal gear ratio in this era trucks with a 4speed?

All of them that I have worked on or looked at in salvage yards had 3.90 gears. 3.38 was supposed to be an option, but I have yet to find one.

Ray

57 Jimmy · 10-09-2010, 09:54 AM

Quote:

Originally Posted by raycow

All of them that I have worked on or looked at in salvage yards had 3.90 gears. 3.38 was supposed to be an option, but I have yet to find one.

Ray

Thanks

10-03-2010, 09:25 AM	#1
alden Registered User Join Date: Jan 2009 Location: pomfret, md Posts: 163	55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? Kindof a specific request. I searched for axle swap info but only came up with a lot of people going with 9" rears for their v8 conversions etc and AD truck info. I want to get a better gear ratio and my current axle needs a rebuild either way, so I'm hoping to go junkyard hunting and find an axle that will give me the following: Keep the 6 lug chevy pattern Keep the same axle length Keep the drum brakes Be a direct swap or at least as minimal effort as required A low 3:xx gear set Does anything match this description? It's going to go on a 1959 3200 longbed fleetside with the stock 235 and 4 speed if that means anything. Thanks! Alden

10-03-2010, 01:06 PM	#2
Knothead Registered User Join Date: Mar 2007 Location: south carolina Posts: 247	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? To retain the 6 lug wheel it will probably need to come out of a truck. I used one out of a 65-66 with a posi unit from the factory. I'm think they were available with Leaf Springs or Coil springs?

10-03-2010, 01:18 PM	#3
The Good Ratchet Registered User Join Date: Sep 2010 Location: Pullman Washington Posts: 15	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? I would look into S10 and S15 pick ups. Many of them run 3.73. The bolt pattern might even line up. Only way to tell is to run out to the junkyard...

10-03-2010, 01:56 PM	#4
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? You don't have a lot of choices if you are looking for a bolt-in. A 3.38 gear was optional in the 55-62 Chevy 1/2 ton rear, but very few trucks actually got ordered with them. Fortunately, 3.38 replacement gears are available from aftermarket vendors. http://www.tomsdifferentials.com/catalog.asp?pg=15 GMC started using the Dana 44 toward the end of the TF years. If you can find a TF with one of these housings, it will be a bolt-in swap. Gear availability is much better than for the Chevy rear. http://www.ringpinion.com/PartsList....ID=15&CatID=10 Because of the scarcity of the above two, most people just go with a 12 bolt and weld on leaf spring mounts. 63-69 (and some 70) are the same width as your stock rear and you can find them with 3.07 gears. 4WD trucks came with leaf springs, but I don't know if the spring spacing matches a TF. It couldn't hurt to measure one though. Ray

10-03-2010, 05:27 PM	#5
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,203	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? I've alway's heard that the older blazer rear ends are good candidates as they have the 6 bolt wheels. The S-10 4X4 are supposed to be good but they wood be a little light. I put a Firebird in my 58 but it has the 5 hole small pattern. It already had that pattern on the front from a disc brake kit.

10-03-2010, 08:09 PM	#6
magicoolbus Registered User Join Date: Jul 2010 Location: Mesa, AZ Posts: 513	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? Patrick's Antique Cars and Trucks in Casa Grande AZ sells a 3.38 : 1 ring and pinon for around 200. http://www.patricksantiquecars.com/chevyparts.htm __________________ JB from AZ 1969 Chevy Sub K10 1957 Chevy 3200 1962 VW Beetle 1957 Willys CJ5

10-08-2010, 03:22 PM	#7
57 Jimmy Registered User Join Date: Dec 2008 Location: Waukesha Wisconsin Posts: 14	Re: 55-59 Nearly direct swap 6 lug, drum brake rear axle with low 3 gear ratio? What is the normal gear ratio in this era trucks with a 4speed? Last edited by 57 Jimmy; 10-08-2010 at 03:22 PM.



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