GM Van 4x4 Core Conversion Kit Standard Lift
This is the Timberline core components kit required to convert your 2500 or 3500 series GM van to 4-wheel-drive. We have worked diligently to compile standardized kits for many different variations of engines, transmissions, and changes throughout the 2003-2023 year model vans.
We provide both core and turn-key conversion kits for these vans. The core kit basically solves for all the non-over-the-counter parts you wouldn't want to build from scratch or design with the hopes of getting it right the first go.
Some of you will only want specific parts we sell, which is why we offer everything a la carte. That said, this kit is the first step in cutting your design and build time way down.
Standard Lift = 2-3" of Lift, 265 75r16 or 265 70r17 tire size recommended.
I'm new to this
If this is your first stop on our site, take a little bit to review the vans, resources, and information on our "How do I convert my van to 4x4" page. We also have answered a lot of frequently asked questions on our FAQ page. If you have further questions, we'd be happy to answer them by phone or Email.
What vans, differential, t-case
2003-2023 GMC Savana/Chevrolet Express 2500/3500/4500 Vans Only (All Engines All Transmissions)
Front Diff Options:
8.25" - 2008-2018 GMC Sierra / Chevrolet Silverado 1500, Suburban, Yukon, Tahoe, etc, typical compatible gearing 3.42, 3.73, 4.10
9.25" - 1999-2010 GMC Sierra / Chevrolet Silverado 2500/3500, Suburban 2500. Recommended 2007.5-2010 years. OE Gearing 3.73/4.10. 3.42 will require changing ring and pinion which we can provide.
Preferred: 2001-Early 2007 Silverado/Sierra NP261,1500,2500,3500 solutions
Other: 29 and 32 spline input GM friendly 6-bolt cases, NP241, NP205, NP263, MP1222, MP1226, MP2225 AWD
Model Specific Notes:
Fuel Tanks / Trans:
Unlike Ford, no fuel tank shortening, exhaust re-routing, or transmission removal in any models.
4L80 - Inexpensive to cut output shaft and just hang the t-case directly or use our adapter for no-cut option.
6L90 - More costly bolt-up 4x4 adapters from Timberline, no transmission disassembly required.
8L90 - Conversion parts available from us, can be done in-vehicle.
4.8/6.0 Gas: Generally the most straightforward of the lot. We have both 8.25"/9.25" diff options, motor mounts can be trimmed in-body, relatively easy clearances.
6.6 Gas: more light-duty fabrication work than other models. We recommend buying our pre-modded motor mounts which clearly outline clearance requirements. 8.25" differential is required for standard lift and recommended for hi-lift. 9.25" can be installed in hi-lift using 2007-2010.5 front diff and our custom oil cooler lines.
6.6 Diesel: pre-2012 models will only fit 8.25" diff with standard lift without oil pan modifications which we don't support. 2012-2016 vans with 6.6 will fit 2007.5-2010 but it's very tight. Hi-lift 4x4 vans will fit 9.25" without issue. Additional fuel filter relocation requirements.
4.3 Gas: 8.25" differential in standard lift, though notching aluminum oil pan will fit 9.25". Hi-lift 4x4 vans will fit 9.25" without issue. We don't support any pre-2017 4.3 Vans.
2.8 Diesel: Most time-consuming but it's totally doable. We recommend our pre-modded motor mounts which cut down on fab time and are easily accessible. 8.25" differential only. Passenger diff mount, exhaust hangars, and fuel filter relocation all require general fabrication skills. Don't try to flatback this one in your driveway.
What is the hardest part?:
Installing the front diff in a van is the most technical aspect of the conversion, but it's very straightforward and repeatable with our kits. Recommended tools include: a vehicle lift, plasma cutter, and some welding ability. Can this be done with an angle grinder, stick welder and jack stands? Absolutely, but expect a reduction in the joy factor.
There is some cutting around the motor mount brackets and work required to relocate the main cross member rearward. We provide metal cut templates for everything and detailed instructions. The nature of the installation is intuitive if you follow the directions and look at the photos. With both 8.25" and 9.25" differentials, installation begins with 1-2 static brackets, and the remaining 1-2 are located using the diff itself. This ensures clearance, leveling, and fitment prior to permanent welds.
We have sold many of these kits and the questions never seem to be about this part of the installation. The most common current questions we get are people asking us to send more components of the turn-key kit.
Here are some sample pages from our GM 4x4 conversion manual. Our manuals include detailed photography, mechanical drawings, torque specs, and helpful tips.
We are dedicated to making the process as straightforward and easy as possible.
Included in kit:
- 4x4 IFS Front Differential Mounting System
- Transmission 4x4 Conversion Kit (4L80, 6L90, 8L90)
- Transfer Case Shiter Kit (4L80,6L90,8L90)
- Hi Clearance GM Center Link ($125 core)
- Rear Lift Kit (Shocks not included)
- Easy-Wire GM Hub Lock & Indicator Kit with AAM motor
- Sway Bar Kit
- Front Shock Adapter Kit
- Front Hub Adapter Rings
- Bump Stop Kit
- Timberline Helper Kit
- Torsion Bar Carriage System
- All Applicable Hardware
- Detailed Full Color Printed/Bound Manual
What else do I need:
- Front & Rear Shocks
- Torsion Bars
- Torsion Keys
- 4x4 Hub Assemblies
- Lower Control Arms
- Trans Mount
- CV Axles
- Transfer Case
- Front Carrier (Diff)
- Front & Rear Driveshafts
We have a standard list of tools that we recommend listed in the front of our manual. Not every single tool is required, but having these at your disposal will facilitate your build. If you are familiar with most of these tools, you're darn capable of pulling this off.
☐ (2) Jack stands
☐ 220v welder w/ shielding gas
☐ Air compressor / pneumatic tools
☐ Angle grinder/cutter
☐ Automotive lift (2 post preferred)
☐ Combination wrenches metric and SAE
☐ Deadblow or plastic-coated hammer
☐ Deadman (Ideally 2)
☐ Drill bits/cutting oil
☐ Electric impact gun
☐ Electric or pneumatic and conventional ratchet
☐ Floor jack
☐ Hose pick
☐ Magnetic lamp
☐ Oil drain and catch
☐ Panel popper
☐ Plasma cutter (It is difficult to complete the GM conversion with only angle grinders)
☐ Pneumatic impact gun
☐ Ratcheting wrenches
☐ Socket, Torx, hex bits sets
☐ Torsion bar tensioning tool
☐ Torque wrench
☐ Transmission jack
☐ Vice grips
Additional Consumable Materials Checklist:
☐ Blue thread locker (If you prefer a different grade that’s acceptable)
☐ Brake cleaner/degreaser of your choice
☐ Brake fluid
☐ Cutting wheels
☐ Gasket maker (TA-29 or TA-31 Ford silicone / AC Delco Equivalent, or Black RTV)
☐ Gear oil ( calls for Full Synthetic 75W-90 ) 4-5 Quarts Front/Rear
☐ PB blaster, WD40 or your choice of penetrating catalyst
☐ Plasma cutter consumables (if you’re using one)
☐ Shop towels
☐ Sanding disks, we use 3” roloc 30 grit, and 2” Scotch Brite discs 2" 3m Roloc sanding disk Scotch Brite
☐ Dex VI Transmission fluid (8L90 + 261 Transfer Cases) Typically 4 Quarts unless servicing transmission during conversion
☐ Welding wire, argon gas
Tips / Skill Level:
1-10 (10 being most difficult) Level 8. We like to equate the conversion to a slightly more involved job akin to a 6" 3/4 ton IFS GM lift kit, only instead of 10 hours of work, it's more like 35-55 depending on your conversion
This product may work with other model vehicles.
Shipping, Fulfillment, Taxes, Quality, and Returns
- Shipping: Our components are carefully wrapped & packaged and ship freight. The quoted fixed shipping/handling price to contiguous US is $325. This covers most commercial addresses in the country. We ship door to door in most of Canada, however, these orders must be placed by phone. We have a license to export to Canada and handle brokering services / GST for you.
- Shipping Additionals: $150 for residential delivery, $100 for liftgate service, High-traffic areas like Oakland/SF and NYC central cost an additional $100. To Avoid additional freight charges please email us with your info prior to purchase. Customers in Colorado may arrange for in-person pickup within 1-2 business days of purchase.
- Shipping/Fulfillment time for core kits: Core kits typically ship within 5 business days of placing your order. In the event that we are unable to meet that timeframe, we will contact you and arrange either a full refund or a timeframe for fulfillment agreeable to the customer. We do not typically allow 1 part to hold up an order, so if this becomes the case, we will freight the full order minus that part and FedEx the remainder at no charge to the customer.
- Taxes: Colorado residents must pay a sales tax of 7.5%. Purchases through our store are charged taxes automatically by Shopify. If you are purchasing a core kit or turnkey kit and are not located in Colorado you may contact us by phone or email to order. We do not collect sales tax on out-of-state sales.
Quality and Returns: We are consistently complimented on the quality of our products and the ease of installation. Fabricated components are generally hand-built here in Colorado by seasoned professionals. Replacement or aftermarket parts are only offered in high-grade options.
If you are in any way disappointed in the components, we will issue a full refund less the cost of shipping when the product is returned within 30 days of receipt. If you decide to return any components that didn't apply to your build or you changed your mind about, a shipping +15 % restocking fee will be deducted from the refund.