Author Topic: C30 Ratio Swap  (Read 6011 times)

Offline COEBill

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C30 Ratio Swap
« on: April 13, 2007, 05:56:37 am »
Hi Guys
 I have a C30 4.56 Ratio Rear End and would like to swap the ratio to a 3.73
What else do I need besides the Crown Wheel and pinion to complete this swap. ???

Bill

Offline Blazin

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Re: C30 Ratio Swap
« Reply #1 on: April 13, 2007, 06:57:17 am »
An installation kit, which should include seals, crush collar etc.Probably wouldn't hurt to swap in new pin, spider gears, wheel bearings, & axle seals too.
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline joesgarage71

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Re: C30 Ratio Swap
« Reply #2 on: April 13, 2007, 11:29:45 am »
 If you have a GM corp 14 bolt, I think the 4.56 gears uses and different carrier than the 3.73 set(www.pirate4x4.com tech section)Not sure about the D60. Something you might want to check out.Maybe someone will chime in and set the record straight.

Steve
78' K-20 355/SM465/twin stick 205 6" on 36's
14 bolt FF/big bearing Dana 44 4.56 gears

92' GMC C-1500 454/4L80E/14 bolt

Offline joesgarage71

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Re: C30 Ratio Swap
« Reply #3 on: April 13, 2007, 11:58:42 am »
I just talked to Randy's and you have to change to a different carrier for both the 14 bolt and the Dana 60.

Steve
78' K-20 355/SM465/twin stick 205 6" on 36's
14 bolt FF/big bearing Dana 44 4.56 gears

92' GMC C-1500 454/4L80E/14 bolt

Offline Blazin

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Re: C30 Ratio Swap
« Reply #4 on: April 13, 2007, 01:18:02 pm »
Might be just as easy to swap out the whole rearend.
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline COEBill

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Re: C30 Ratio Swap
« Reply #5 on: April 14, 2007, 02:00:55 am »
Hi Guys
 Thanks for all the input, very much appreciated.
Where I live in Down Under Land (Australia) 3.73 Ratio's were not available, only the 4.56 and 4.41 or 4.14 can't remember which way the numbers go.
So it would be much lighter to import the required parts or a housing and Centre I suppose.
Oh yeah and it is a GM corp 14 bolt

If anyone has more info on the subject please let me know.

Regards
Bill 

Offline Blazin

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Re: C30 Ratio Swap
« Reply #6 on: April 14, 2007, 09:14:43 am »
Well welcome from New Hampshire USA.
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline VileZambonie

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Re: C30 Ratio Swap
« Reply #7 on: April 14, 2007, 09:50:11 am »
If you've never set up a differential and final drive before and don't have a pinion depth gauge along with a very good understanding as to how it works I don't consider this a DIY job. The reason I say this is because I can't tell you how many I've had to re-do after someone tried swapping the ring and pinion in and out. So if you've never done it before make sure you have the correct tools and a calculator handy. As far as the Carrier is concerned it's 4.10 and numerically lower you can change the ring gear. For your 4.56:1 you will need a new one like this http://www.4wheelerssupply.com/catalog/product_info.php/products_id/71166
Is your's a full floater?
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline COEBill

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Re: C30 Ratio Swap
« Reply #8 on: April 15, 2007, 03:01:11 am »
I would not be attempting to do this conversion myself but would take it to the experts.

Full Floater, I think so  ???

Regards
Bill

Offline VileZambonie

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Re: C30 Ratio Swap
« Reply #9 on: April 15, 2007, 10:04:03 am »
If you look at the end of the axle are there bolts going around in a circle holding the axle in? Better yet got any pics?
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline COEBill

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Re: C30 Ratio Swap
« Reply #10 on: April 16, 2007, 07:36:57 am »
Yes it has got the 8 bolts holding the axle in, so I guess that makes it a full floater.
This is all a big learning curve for me.

Regards
Bill

Offline joesgarage71

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Re: C30 Ratio Swap
« Reply #11 on: April 16, 2007, 07:30:08 pm »
Yes Sir.
78' K-20 355/SM465/twin stick 205 6" on 36's
14 bolt FF/big bearing Dana 44 4.56 gears

92' GMC C-1500 454/4L80E/14 bolt