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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: COEBill on April 13, 2007, 05:56:37 am

Title: C30 Ratio Swap
Post by: COEBill 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

Title: Re: C30 Ratio Swap
Post by: Blazin 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.

Title: Re: C30 Ratio Swap
Post by: joesgarage71 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

Title: Re: C30 Ratio Swap
Post by: joesgarage71 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

Title: Re: C30 Ratio Swap
Post by: Blazin on April 13, 2007, 01:18:02 pm

Might be just as easy to swap out the whole rearend.

Title: Re: C30 Ratio Swap
Post by: COEBill 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 

Title: Re: C30 Ratio Swap
Post by: Blazin on April 14, 2007, 09:14:43 am

Well welcome from New Hampshire USA.

Title: Re: C30 Ratio Swap
Post by: VileZambonie 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?

Title: Re: C30 Ratio Swap
Post by: COEBill 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

Title: Re: C30 Ratio Swap
Post by: VileZambonie 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?

Title: Re: C30 Ratio Swap
Post by: COEBill 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

Title: Re: C30 Ratio Swap
Post by: joesgarage71 on April 16, 2007, 07:30:08 pm

Yes Sir.