Click on image for the lowdown. 
====
| | |
7 members (55Delray, Steve L., Bill Hanlon, MickeyP, WICruiser, Bucker, 1 invisible),
64
guests, and
2
robots. | | Key: Admin,
Global Mod,
Mod | | | Forums66 Topics128,206 Posts1,057,435 Members48,471 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | 
#35571 02/01/2004 6:54 AM | Joined: Feb 2003 Posts: 58 Shop Shark | | Shop Shark Joined: Feb 2003 Posts: 58 | I have a 56' 1/2 ton rearend that I am considering putting in to one of my other trucks and change the gearing in it.
I am interested in changing it into either my 51' chevy 3/4 ton which has a 4.90 gearing or my 49' 1 ton with 5.14 in it.
I also want to change the front to a six bolt and need to know if there is anything I can put right on the axle.
If I can change the rearend I hope to put a T-5 tranny in with it.
I think this would make it easier on the engine if I can do all this.
Collecting is fun, as long as momma enjoys riding in them.
| | |
#35572 02/01/2004 7:33 AM | Joined: Apr 2002 Posts: 1,571 Shop Shark | | Shop Shark Joined: Apr 2002 Posts: 1,571 | You can get a '68-'72 center section that will fit the 3/4 and 1-ton axles (provided that they are not torque-tube axles). These had an optional 4.11 gear ratio. They were often found in trucks with automatic transmissions, but mine came from a 4-speed truck. It might be another option to consider. If interested, search the archives as this swap has been discussed several times. | | |
#35573 02/01/2004 7:49 AM | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | The standard ratio for 55-62 1/2 ton is 3.9. There were 4.11,3.7,3.38 optional ratios also.
See the USA in your vintage Chevrolet! My Blog | | |
#35574 02/01/2004 8:15 AM | Joined: Feb 2003 Posts: 58 Shop Shark | | Shop Shark Joined: Feb 2003 Posts: 58 | How should you be able to tell which it is?
Collecting is fun, as long as momma enjoys riding in them.
| | |
#35575 02/01/2004 5:33 PM | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | Divide the number of teeth on the ring gear by the number of teeth on the pinion. A 3.9 will have 39 on the ring and 10 on the pinion.
See the USA in your vintage Chevrolet! My Blog | | |
#35576 02/01/2004 6:42 PM | Joined: Jul 2003 Posts: 252 Shop Shark | | Shop Shark Joined: Jul 2003 Posts: 252 | The pinion gear will also have a date code, and the number of teeth stamped right into the top of it. The pinion in my 61 Apache has GM 11-60 39-10 and a part number stamped in it. The 39-10 being the tooth count for the gear set. | | |
#35577 02/04/2004 8:57 PM | Joined: Jan 2004 Posts: 288 Shop Shark | | Shop Shark Joined: Jan 2004 Posts: 288 | Hey, would anyone know the standard gear ratio on a 55 first series? I have a 68 camaro 283 small block with a 4 speed borg warner transmission. I am assuming that I have the original truck rear end. I would like to go to a lower gear but am not sure what gear ratio I have. Truck is in storage right now and I won't be able to get at it till this spring.
thanks,
Chris
Chris 1955FirstSeries
| | |
|
|
