4 Inch Custom Spring System Lift GMT 400 SAS GM D44 10Bolt 52 Inch Springs
Kill two birds with one stone!
Remove that weak IFS and get a comfy ride with our custom springs!
All in one easy package
Check out the FAQ, Instructions, and Product info at the bottom of this page for all the ins and outs of this lift!
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What are the benefits of the Offroad Design Custom Spring System for your Solid Axle Swap?
Plush on road ride
We take in account all the information on your truck to build you the perfect riding leaf spring possible. This isn't some off the shelf spring built for every truck, this spring is built specifically for your truck. Going from a typical lift spring to our custom springs is a true night and day difference! It is the best possible ride while staying on leaf springs.
Off road flex
With our multi, thin leaf design our spring packs can flex farther without bending. A typical pack is around 10-12" Vertical travel
High quality build
Our springs are made in the USA with USA Steel. We use a military wrap main eye for extra durability. All the springs are dip coated black.
Unlike stock springs or typical lift springs, our custom springs can take a beating and ask for more. They are designed to flex and retain their shape where others go flat
Our springs get all this amazing ride/flex while being able to bolt into the stock locations. No need to go with longer springs
Are the custom springs in stock?
The custom springs are just that, custom so each set is built to order and designed to fit your truck perfectly. The wait is definitely worth it!
What are the Kevlar Bushings?
Our Kevlar bushings are a high tensile strength bushing that is built to last! They are also soft enough to not hurt the ride. These bushings are designed with grease channels to help flow to all parts of the spring eye
Solid axle swap info
Why Solid Axle Swap your 88-98 GMT 400?
If you're fed up with constantly replacing front end components, expensive lift kits, front axles that don't hold up to bigger tires or you just want the trail performance of a solid axle this kit is for you!
How does this kit install?
Bolt on installation, drilling holes required but we use all the existing holes that we can
We have 3” of lift built into the brackets, but don’t worry we account for this lift when we design the custom springs. For example, if you want a total of 3” of lift, we build a 0” lift spring.
The brackets move the axle 1” forward. This is to help with tire clearances and approach angle. We can move the axle farther forward with the custom springs if you like, just select in the options.
Crossover steering is the only way to go with a solid axle swapped vehicle. You can retain your stock steering box.
Dana 44/Corporate 10 Bolt
A flat top knuckle is needed to bolt the crossover steering arm to the axle. Below is an example of what a flat top knuckle looks like to check to see if your axle has one The flat top is on the left. If you do not have a flat top knuckle you will need a Reid Racing knuckle which we do have. The one thing to check to match is the orientation of your tie rod, Nut up or Nut down. This is the direction of your castle nut. If you do not match your drivers side knuckle you will not be able to install your tie rod.
Transfer case info
Passenger drop Axle
When using a passenger side drop axle you will need to switch out the transfer case The transmission does need to be the 4WD version so 2WD transmissions will need to be converted. Adding in any of our gear reduction systems is relatively easy, give us a call to discuss those options. Swap info for a single transfer case is as follows, there are three main options:
This is an easy option because it has the same bolt pattern as the 88-98 transmissions and is a fairly durable transfer case using up to 37" tires. If you have a 700R4/4L60E, you'll want to find an NP208 from behind a 700R4 and those came in most 81-87 Chevy 1/2 tons (88 Suburbans and Blazers too!), these will have a 27 spline input. Those will bolt right in, the only issue is the 208's use a cable driven speedometer and the 4L60E needs an electric speed signal to shift correctly. That can be solved by installing an adapter that creates an electric signal from the cable drive, you can also put a manual valve body in the trans. If you have a 4L80E or any of the manual transmissions, you'll need to find an NP208 from a TH400 or an SM465 four speed manual, those will have a 32 spline input. Again, the NP208 will bolt right up in place of the factory transfer case. The 4L80E will need an electric vehicle speed sensor or a manual valve body, the manuals will only need an electric speed sensor if you want the OE speedometer to work.
Another easy option because it bolts right up in place of the factory transfer case on the 88-98's, same duty level as the 208. NP241's came in 89-91 Blazers and Suburbans and they are passenger drop, the 1989 models have a cable driven speedometer just like the 208. The 90 and 91 models, however, use an electric speed sensor in them from the factory so this makes them a very desirable case for solid axle conversions, though they aren't as common as the 208. The 241 is the same story as the 208, if you have a 700R4/4L60E, look for a 241 from a 700R4. If you have a 4L80E or any of the manual transmissions, look for a 241 from behind a TH400.
The NP205 is the strongest choice, but doesn't bolt directly to any of the 88-98 transmissions. If you have a 700R4/4L60E transmission, you'll want the 205 and adapter system from behind a TH350 transmission. You'll need a shorter output shaft or a spacer: https://www.offroaddesign.com/700r4-4l60e-short-output-shaft.html https://www.offroaddesign.com/700r4-spacer-1-7-8-inch-with-bolts.html and if it's the later 6 bolt tailhousing (with a removable bellhousing) you'll need a 6 to 4 bolt reducer. If you have a 4L80E transmission, you have two options to get a 205 on it. You can use an '84 and older figure 8 pattern NP205, swap a long 32 spline input gear into it and use a TH400/fig 8 205 adapter that needs minor machine work to fit the 4L80E. You can also find an '85-91 GM 205 that will have a six bolt round pattern on the front, the input gear needs to be swapped to the short 32 spline version (direct swap) and the factory adapter needs to be notched, then it bolts up. If you have any of the manual transmissions, you'd need to find an '85-91 GM round pattern 205, swap it to the short 32 spline input gear (direct swap) and notch the tail housing of the trans, then it bolts up.
2wd 2500 and 3500 frame info
2wd 2500 and 3500 frame info
The 88-98 Chevy 4WD 1500, 2500 and 3500 frames and the 2WD 1500 frames are all very similar and our solid axle conversion works on those trucks without issue. The 88-98 2WD 2500 and 3500 trucks are different. Their frames drop down lower then curve up at the front and do not have a flat part to attach the spring hangers to. It is possible to put a solid axle under these trucks but the frame will have to be modified to mimic a 4WD truck or you'll have to graft 4WD front frame rails on to the 2WD frame.
Bilstein shock info
Why use Bilstein shocks
Bilstein is a great all-around shock that is extremely durable. We have selected a valving that is an amazing pair with our custom springs and offers good on and off road ride
Front Drive Shaft
Swapping to a solid axle up front requires a new front drive shaft. The stock IFS drive shaft will no longer work. With our custom springs you will have a lot more travel compared to a typical off the shelf spring, a long slip front drive shaft is usually needed
Rear Drive Shaft
Typically the rear drive shaft still works but it is worthwhile checking to make sure.
After lifting a vehicle the angle of the drive shaft typically changes. Sometimes the pinion may need to be shimmed to prevent vibration. This cant be checked until after everything has all been installed. We do carry shims to help correct if needed.
Towing and Hauling
Our springs are designed to give the best ride possible, so they have a low spring rate. To get the best of both worlds (nice ride and towing capacity) we recommend using a set of airbags when towing. There are quite a few kits out there for airbags on these trucks. One thing we highly recommend is the daystar airbag cradles, they allow the airbag to leave/return to the cradle when flexing off road. That way your suspension travel isn’t hindered, we carry them on our website too!
Throwing a few hundred pounds of gear in the back of your truck is not going to be a problem. When you are looking at hauling more than that we recommend using airbags
What banjo bolt do I have on my calipers
What banjo bolt do I have?
Our custom spring lift systems come with option of Stainless steel braided brake lines. These lines are DOT approved and pressure tested for leaks. These line will connect directly to your stock hard lines. You will need to select what size banjo bolt fitting you have. As a rule of thumb 1978 and older trucks got 7/16 banjos and 1979 and later got 10mm, to be certain you should measure the threads of your banjo bolt. This can not be determined by what size wrench is on the bolt head. You will need to measure the threads with a caliper like pictured You will also need the adapters, make sure to select the option when adding brake lines.
What is this kit for?
GMT400 with a GM Dana 44 or Corporate 10 bolt
This kit will work with 88-98 GMT 400 trucks and SUV's that are swapping in a GM Dana 44 or Corporate 10 bolt. This kit will be using a 52" front leaf spring.
Tire Size Info
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|Greasable Rear Bushing Instructions||419.9 KB||Download|
|Dana 44 and 10 Bolt Crossover Instructions||358.4 KB||Download|
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