04-12-2021, 11:38 PM | #1 |
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Rear differential
I have a 1960 gmc step side it has a 4:10 gear ratio in it . I would like to change the ratio . I’m thinking 3:55 .
Would still like a good start of the line but need a highway gear too. Also does anyone have a suggestion for a supplier. Don’t want to change the axle just the differential. |
04-13-2021, 12:36 AM | #2 |
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Re: Rear differential
Is this the HO32 rear end (removable center section AND removable rear cover)? I don't think you will find -any- gears for it.
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1961 Apache: "Grabber Orange" Shortboxed, pancake, step-notch, air-ride, turbo, LS 1977 Silverado: Shortboxed & dropped, potato-potato V8 Pontiac Firefly (Chevy Sprint): The ultimate engine swap: 5.7L in a 1.0L bag Lotus Super 7 Replica: Scratch-built street-legal rollerskate |
04-13-2021, 08:01 AM | #3 |
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Re: Rear differential
Ok
Thanks Obviously I need to identify exactly what I have first. Possibly not as easy as I’d hoped. So what does everyone do ? Drive around with 4:10 gears or is there a rear axle swap that’s relatively simple . I have a 454 with a 400 turbo 3 speed and I need to improve my highway rpms |
04-13-2021, 08:08 AM | #4 |
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Re: Rear differential
Hey SkinnyG
I looked at your Apache project.......great job , I love it. |
04-13-2021, 10:50 AM | #5 |
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Re: Rear differential
Thanks!
You could swap just about any axle relatively easily. You'd need to weld on axle mounts. 60-62 is a different width than 63+, so even swapping a later axle requires welding mounts. I'd go 63+ 12-bolt or even a Ford 8.8. Keep in mind bolt pattern and such. You could swap in a 5-speed. Be gentle though, a 454 has a lot of torque. You could find a 4L80E for the overdrive and get a trans controller for it.
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1961 Apache: "Grabber Orange" Shortboxed, pancake, step-notch, air-ride, turbo, LS 1977 Silverado: Shortboxed & dropped, potato-potato V8 Pontiac Firefly (Chevy Sprint): The ultimate engine swap: 5.7L in a 1.0L bag Lotus Super 7 Replica: Scratch-built street-legal rollerskate |
04-13-2021, 03:52 PM | #6 |
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Re: Rear differential
I have a '60 with the DANA 44, called Precision Gear and bought a 3.23 (stock was 3.92), I changed all the inner and outer bearings while I was at it too.
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04-13-2021, 07:55 PM | #7 |
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Re: Rear differential
I'm thinking going to a 3.55 still isn't a big enough change to get you what you're looking for. I feel a 454 has plenty enough torque that it should still smoke the tire with a 3.08
Last edited by AcampoDave; 04-13-2021 at 08:02 PM. |
04-14-2021, 02:06 AM | #8 |
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Re: Rear differential
If it is an HO32, Yukon has a 3.38 ring and pinion.
https://www.yukongear.com/partslist....nion+Gear+Sets
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04-14-2021, 09:04 AM | #9 |
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Re: Rear differential
Thanks , I was wondering about that.
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04-14-2021, 09:25 AM | #10 |
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Re: Rear differential
Thanks everyone for your input .......I really appreciate it.
I think I will go with the 3:38 Yukon Ring and Pinion. Next question other than a new diff gasket and cover what other parts would I buy as well. I’m relatively sure nothing has been done to the rear end previously. I’m a rookie at this. I will purchase parts but have some qualified help for the install. |
04-14-2021, 10:35 AM | #11 |
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Re: Rear differential
Oh cool!
I've previously run Yukon gears - they are very good.
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1961 Apache: "Grabber Orange" Shortboxed, pancake, step-notch, air-ride, turbo, LS 1977 Silverado: Shortboxed & dropped, potato-potato V8 Pontiac Firefly (Chevy Sprint): The ultimate engine swap: 5.7L in a 1.0L bag Lotus Super 7 Replica: Scratch-built street-legal rollerskate |
04-14-2021, 05:32 PM | #12 |
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Re: Rear differential
from my experience / while you are in there ....
The bearings are R1502EL - available from several manufacturers including Timkin and National The seals are : SKF 18695 - also interchangeable and available from several manufacturers / vendors. (the best prices I found was on RockAuto, searching by PN). Somebody else made a good point - above parts are for the Eaton HO 32/33
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1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... Last edited by 60short; 04-15-2021 at 10:39 PM. |
04-15-2021, 01:47 PM | #13 |
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Re: Rear differential
take a pic of the rear cover and post it. Most GMC's had a Dana rear axle.
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04-15-2021, 03:12 PM | #14 |
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Re: Rear differential
lucky you! most of us just tool around in our 4.57s day dreaming about 4:10s
cross your fingers you've got a dana under there and good luck finding a suitable gear swap!
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