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Parts back in stock! We have just about everything available for purchase now and have ironed out our production! Stay tuned as products are updated and populated this week! (Update 6/6/22)
Parts back in stock! We have just about everything available for purchase now and have ironed out our production! Stay tuned as products are updated and populated this week! (Update 6/6/22)

Differential Mount System (standard) for 9.25 IFS 4x4 GM Van Conversion


This kit contains all the necessary components to mount a 9.25 IFS GM front differential from a 3/4 or 1 ton Silverado ('99-'10) to an Express or Savana 2500 or 3500 (2003-2022) with just a handful of limitations**

** See fitment notes below for additional constraints.  (This kit most comfortably fits gas 4.8, 6.0 and 6.6 vans, but will fit other designs.)

Mounting the diff is the most complex part of the IFS GM conversion but we have developed a straightforward and easily repeatable means to do so.

This kit comes complete with template cutouts for the frame extension mods that have to be made, step-by-step instructions with lots of photographs on how the cuts should look, and a comprehensive set of hardware and brackets that only fit together one way. 

If you're a DIY builder building a Coilover van, a lowered AWD hotrod van, or any number of the other odd calls we routinely get, this is the one kit that will keep you from pulling your hair out over the build. 

This version of our kit is suitable for vans lifted 0"-3" We also offer a 5" lift conversion option in both coilover and torsion bar configurations.  

NOTE: This system will interface with other popular brands of 4x4 conversions. If you are trying to replace a specific similar component seen in this kit for your other brand of 4x4, please contact us for more information. 

Fitment Notes: 

Van Side 

  • 2003-2022 Chevrolet Express 2500/3500/4500 series vans with 4L80 and 6L90 Transmission (4.8L, 6.0L, 6.6L-gas)
  • 2017+ 8L90 transmission vans with cast motor mounts require replacement with steel mounts and additional trimming
  • 2003-2016 4.3L engines likely fit, but no support provided
  • Motor mount brackets can be trimmed while still in the vehicle. If you would prefer to have us prefab motor mounts to swap in, email for more info
  • 2010.5-2016 Duramax LGH engine vans require significant carrier case clearancing
  • 2003-2010 4L80 Duramax engine vans require substantial additional fabrication to clearance oil pan/mounts for diff. Documentation not currently provided.  5" Lift kit substantially simplifies general fitment. 
  • Updated design substantially mitigates clearance issues with face of diff where tie-rod center link pivots past. We have seen issues with this on (3) other conversion companies' vans that build a similar product. 
Tools Required:

Standard hand tools, pneumatic tools, and torque wrench recommended, requires welding, cutting time significantly improved with a plasma cutter and undercoat removal facilitated with an acetylene torch or propane.


Timberline front cross-member, left plate, right differential support with bushing assembly, makeup plate, upper bracket, Timberline center link, all appropriate hardware, frame extension trim templates, and printed/bound color installation manual. 

Construction Notes:

1/4", 3/16" material CNC cut A36 mild steel, serviceable motor isolator sleeved bushings, grade 10 and grade 8 hardware, powder-coat

Tips / Skill Level:

1-10 (10 being most difficult) Level 8

This product may work with other model vehicles. 

It is a tight fit! It should be, this keeps the differential tucked up and out of the way, giving you the best ground clearance possible up front without requiring a large vehicle lift or compromising drivability. 

The 9.25 IFS differential should be the same in all 2500/3500 trucks years 1999.5 to 2010, though we have never built one with a differential earlier than 2005. The available gear ratios from built were 3.73 and 4.10. Most gas vans are 3.42 ratio. We offer a reverse 3.42 ring and pinion gear for regears. We also offer 3.73 and 4.10 gear options for rear differentials. If you are going up in tire size, this can often be a better solution. 

You can find diffs on used. The most common service step is to replace the axle shaft seals, other than that, they're pretty bomb-proof. 

Shipping, Fulfillment, Taxes, Quality, and Returns
  • Shipping: Our components are carefully wrapped and packaged and ship UPS, USPS, or FedEx, depending on what is available. If you require a particular carrier, please contact us ahead of your purchase.  Customers in Colorado may arrange for in-person pickup within 1-2 business days of purchase. 
  • Shipping/Fulfillment time for components: We typically ship within 1-2 business days of your order and we carefully monitor our inventory. 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. 
  • Taxes: Colorado residents must pay sales tax of 7.5%, no sales tax is collected on out-of-state shipments currently. 
  • Quality and Returns: We are consistently complimented on the quality of our products and the ease of install. Components are hand-built here almost exclusively in Colorado by seasoned professionals who are fanatics about design and execution. 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. If you decide to return any components that didn't apply to your build or you changed your mind about, shipping and a 15% restocking fee will be deducted from the purchase refund.