Nuts & Bolts: Chevy Solid Axle Swap With Leaf SpringsPosted in How To: Tech Qa on March 15, 2016
Chevy Solid Axle Swap With Leaf Springs
I have 2002 Silverado 1500 4x4 5.3L extended cab, and I want a mild lift with stock rubber for now. But I want to achieve this lift with a regular 1/2-ton (maybe Dana 44 sized) solid axle out front (even if it requires retubing) supported by leaf springs, sort of like a Jeep CJ–style suspension (no control arms to keep things simple). Five- or six-lug, doesn't matter, and I'd prefer to keep my stock 3.73 ratio. I know this would mean a custom driveshaft and/or different rear springs as well. How might I go about this? Would it be possible to use the factory IFS knuckles on a solid axle, with custom steering of course, to utilize the factory hubs?
One more thing. Could I or anyone else make custom axleshafts that could use those smooth CV ends from the factory? I'm not too worried about high strength here.
There’s a lot of information out there regarding Chevy solid axle swaps, even those running leaf springs as opposed to coil springs and control arms. Our recent build of Rosco P. Drivetrain is a great template for going the latter route. The same build could just as easily have been done with coils versus the coilovers that Technical Editor Verne Simons used in the build. His Tahoe started life as a 2WD truck, but the process is largely the same. You can view all eight installments of the build on our supersite, fourwheeler.com.
Both Off Road Unlimited (offroadunlimited.com) and Offroad Design (offroaddesign.com) have been doing solid axle Chevy swaps for years, so both companies are a great resource for information on solid axle swaps in general. That said, neither company currently offers a bolt-on kit for your 2002 1/2-ton, as their current offerings are limited to 1988-1998 Chevy trucks and later-model 2500 and 3500HDs. Your 1/2-ton frame is different than the HDs, so you are on your own for brackets. However, some of the general points of these other conversions are still applicable.
The main problem with your proposed build is wanting to stick with a mild lift and leaf springs. Both ORD and ORU point out that their kits add about 3 inches of lift over whatever spring height is chosen. In other words, a 2-inch lift spring will net 5 inches of lift. This is an inherent part of making spring mounts to accept leaf springs on an IFS frame. Keeping lift height conservative with leaf springs is going to be difficult, as even stock-height 1973-1987 Chevy springs are going to create 3 inches of lift on your truck. You may also run across clearance problems between the solid front axle and the engine crossmember that will need to be addressed with a small amount of lift. You might have better luck going with coil springs and control arms to keep lift conservative, hence why we brought up our Rosco P. Drivetrain project. But again, while you can use the off-the-shelf solutions as guidelines, you will be largely on your own in terms of fabrication and execution. Custom steering, a front driveshaft, and much more will also be required. Make no mistake: Your proposed swap will take a lot of time and require serious fabrication skills.
As for your axle questions, no, there is no way to convert an IFS knuckle to a solid axle or mate the IFS wheel hubs or CV axles on your truck to a solid axle. You are going to need a complete donor axle with a differential offset to the driver side in order to work with your transfer case, and a rear axle with a matching wheel bolt pattern. This means a front axle out of a Ford truck (1973-1979 F-150, F-250, or F-350; 1993-1997 F-350; or 1999 and newer Super Duty) or out of a 1994 or later Dodge truck. Or you could custom-order an axle from companies such as Currie Enterprises (currieenterprises.com) and Dynatrac (dynatrac.com). To our knowledge, no driver-side diff front axle donor will yield the correct six-lug bolt pattern to match your rear axle out of the box. If you are going through all the trouble of an axle swap, it would make sense to go with bigger axles out of a 3/4- or 1-ton truck anyway, as the C-clip rear axle in your truck isn’t particularly strong or desirable for serious off-road use.
There’s a lot to a swap like you propose, so it’s best to be sure where your priorities are for your needs and uses. Going taller might make things easier, and getting the right donor axle is going to be important. While you won’t necessarily be treading new ground, the devil is in the large and small details when it comes to making the whole project come out right.