Timberline GMC / Chevrolet 4x4 Conversions

The Important bits

Conversion years serviced: 2003-Current.

Cost: $15k-$25k options dependent. (Most vans $16k-ish)

Lift considerations:

  • Option A) 1"-3" of lift, torsion bar design, best price, closest to OEM, 

  • Option B) 6" of lift, torsion bar design (more $$, but loads of clearance and it still drives great)

  • Option C) (In Design) 6" of lift Coilover IFS design - Pricing fall 2021, Booking 2022 (High end.)



  • Vehicle length capped at 23 feet

  • We offer conversions for all engine and transmission options except early 2500 models with the 4.3 V6 and 4L60 transmission

  • Conversions are limited to 2500/3500/4500 series vans, we do not offer 1500 series conversions or AWD to 4WD conversions for the H series vans

  • We are open to discussion for AWD 2500/3500/4500 series conversions for commercial applications only


Pricing: $14,500+upgrades/mods base price

  • Gearing Options

  • 3.42 Gearing add $1150

  • 3.73 Gearing add $1350 (includes Limited Slip Differential)

  • 4.10 Gearing add $1350 (available on 6" Lift only, includes Limited Slip Differential)

Tire Sizes

  • 1-3" Lift Recommended tire sizes 265 75 16, 265 70 17

  • 6" Lift Recommend tire sizes 285 75 17, 285 75 18

Wheels: OEM wheels and tires will work, aftermarket/higher offset wheels available sourced through Timberline


  • Approx 2-3 week turn around (for conversion alone)

  • Scheduling varies, call for details

Additional Price Modifiers

  • 6" Lift - total redesign includes custom knuckles, additional carriages, diff skid plate, offset ball joints, rear leaf springs (no blocks). add $4300

  • Cab/Chassis variants: Minimum add $1500

  • 6.6 Liter Duramax variants: Minimum add $1000

  • Sliding door modification for high offset clearance (vehicle depending) add $850

  • 2018+ Vans add $350 for 3.73/4.10 gearing 

  • Short Wheelbase Vans add $500 for evap relocation, additional transfer case modification. 

Additional Work

  •    Upfitting and reconditioning available, we currently handle everything but pop-tops. 

  •    Shop rate $95/hr Fab Rate $115/hr

For more information on how the conversion process works, visit the CONVERT MY VAN page. 

build (GM)


About our conversion:

Our IFS GM van is designed around factory parts and we fabricated the remaining components to be similar to what GM would've done had they made a 4x4 1-ton van. This rig features a high/low 2-speed transfer case, the option of 1" to 3" lift over stock, and from OEM 245 75 16 to modest 265 70 17 series tires. 

All fabricated components are powder coated for longevity, or epoxy painted post-weld-in. Our GM vans drive basically like a conventional 2 wheel drive van, and when we upfit to a slightly larger tire size we usually opt to re-gear accordingly so even the 4.8 gas vans run circles around many Fords.


The GM van is easy to get in and out of and has similar ground clearance to a crew chevy pickup. All 4x4 components are 1-ton design or larger, 2-3 times the size of what you'd see on an AWD G1500 van. Vehicle can be easily serviced at any normal shop, maintains factory anti-lock brakes and traction control systems, and we will provide you with a build sheet for all serviceable items so you know exactly what parts you need to keep it on the road for years to come. 

Important stuff

Service: Vehicle can be easily serviced at any GM dealer or conventional mechanic

Parts List: Parts list of serviceable items provided on every vehicle, so you know what you have in the future

Front End: Independent front suspension, 2500/3500 series 3rd Member (remanufactured) 3.42/3.73/4.10 gear opt.

Transfer Case: Manual shift NP261 (NV261) from 1 ton K series truck

Transmission: Unchanged, precision machined steel adapters, powder coat, hardened Chromoly spline shaft adapter, or OE Extension housing, Billet Aluminum Adapter. (Dependent on year)

Stability: Design does not impact ride stability, heavy-duty sway bars available.

ABS, TCS, RSC, ETC: Factory ABS and stability systems maintain functionality across all sub-models

Emissions/Smog: All factory emissions equipment across all sub-models remains functional

Parts: Serviceable components are all off the shelf parts available OEM or aftermarket equivalent

Standard Lift: 1" to 3" lift options. With our standard conversion, the most comfortable ride is a 2" lift. 

6" Lift: Our 6" Lift option utilizes different lower control arm brackets, custom cast, and machined knuckles, high performance adjustable upper ball joints, 5100 series Bilstein shocks, front differential skid plate, different torsion bar carriage, and leaf springs in lieu of lift blocks for the rear of the vehicle. Our leaf packs for GMs are available in 2 different weight ratings dependent on your van build. 

Tires: 245 75 16 up to 265 70 17 recommended, 275 70 18 fits the standard lift with heavy trimming. Our larger lift option will fit 34" tires with light trimming and may fit up to 35" with more significant trimming. The shape of the Express/Savana wheel well requires a significant lift to achieve a larger tire. 

What's included

New parts: New front hub assemblies (Moog, Timken or SKF), new over the counter CV axles, brake rotors, brake pads, lower control arms with ball joints (Moog), Moog torsion keys and hardware, rebuilt NP261, steel front driveshaft, aluminum single-piece rear driveshaft, all new grade 10 hardware/bushings, manual shift t-case with automatic locking hubs (electric), 4x4 indicator lamp, custom t-case linkages, new lever and ball. We have a few other updated designs including a modified steering center link that has been a clearance issue on other popular conversion companies' vans for years. Other improvements include bolt-on sway bar adapters that don't crack, skid plate availability for front differential, improved serviceable wiring harnesses, sensors, serviceable shifter boot, and other over the counter components where competitors require custom replacements. 


Notes: All hardware for conversion is grade 10 and grade 8 certified with zinc coating where available. Conversion does not require new wheels or tires, but most people opt to change them during conversion. Timberline requires 8/32 minimum even tread on tires if you intend to re-use them. OEM TPMS system remains functional. All fabricated components are powder coated for longevity and salty climates. Heavily welded-in components will be epoxy painted by hand before the vehicle is assembled as powder coat is burned off during install. Conversion includes fresh alignment. 

Remanufactured: Torsion bars, front differential, rear differential (3.73/4.10 gears)

Warranty: Our outside conversions come with a 12 month 12,000-mile parts warranty. Vans with under 10k miles come with a 24 month 24,000-mile parts warranty. Labor is included for Colorado customers only. Parts warranty is limited to manufacturer or installation defect. We do not offer any guarantee of upholding manufacturer warranty, eg. Chevrolet, however we have converted many new vans without complaint. 

What we work on

Van Condition: We work on nice vans without rust. It's not a prequisite that the van has low mileage, or is a certain year, but it needs to be nice. We do not work on anything with rust or extensive body damage, or significant mechanical issues that will not be addressed as part of the conversion, etc. It doesn't make sense to spend a lot of money on a dilapidated vehicle. We realize all vans are used and have personality, but please buy and bring nice rigs for us to work on. 

Additional Upfit / Labor / Payment

Additional labor rates

  • Shop Rate + Mechanical Work: $95/hour

  • Specialty Diag / Custom Labor + Fab: $115+/hour 

Payment: On a conventional conversion, we require $9,000 down at the time of van being dropped off. The balance is due on delivery. If you have additional upfit requirements, an additional down will be required. Non-Colorado residents must pay the balance with certified funds, cash, or credit/debit. We accept all major credit cards, however, there is a 2% charge for anything more than $4,000. Colorado residents must pay tax on applicable parts.


When your van is finished, you can schedule a pickup which only takes about 20 minutes. If you are out of state and want your van delivered we can help with that. We also offer free airport pickup if you'd like to fly in and drive your van home. If you need some time to get here, we can store the van for you for up to 30 days. Additional storage of vehicle may incur fees as we are limited on space.

You will receive a build sheet with the details of your conversion components for future service and we will spend whatever time you need to explain your new setup. We generally take folks on a quick 5-10 minute test drive to go over the 4x4. Balance due by cash, certified funds, or debit card for the balance. Credit card payment fee schedule same as at drop-off.

Colorado Residents:

Timberline will collect applicable sales tax on parts used in the conversion process. A good deal of the components used already have taxes paid on materials. 

We offer a free 1000 mile checkup on your van, just to bring it in and shake it down, check for any details needing attention. If you are in metro Denver, we offer free pickup and delivery service of your van.