If you’re looking to make big power AWD in a medium to heavy weight car (—or more likely—truck) without breaking the bank, the new venture (later new process) 149 t-case is your box! After a few customers looking to go AWD pestered me into doing the research, I’ve found these beasts!
GM drivetrain hit another homerun selecting and specifying this unit. They combined simple operating principles with excellent metallurgy for another winner in toughness and longevity. The unique viscous coupler design is extremely robust and has a great 38/62 front/rear torque bias which then transfers more power front to rear as the weight transfers on a dig launch. from a roll, the 38/62 has a mild-yet-solid hit (gm calls it “the hump”) which keeps the vehicle stable even at speed. No computer controls needed. In fact these pair great behind a factory 4wd 4L80e as the 149 output has the 40T speed sensor most transmission control systems require but factory 4wd 4L80’s omit.
My upgrades to this unit include a billet 32spline input shaft from AMP drivetrain, oversize Borg Warner gears and chain from duramax spec np261xhd 1/2” wider than the factory 149 chain. I also update the output shaft bearing retainer and add a pump-rub prevention plate, eliminating the most common failure mode (case wear-through and complete lube oil loss)
I round out the unit with top shelf name brand roller and needle bearings.
GM rates these STOCK at 1900ft lbs and with my further upgrades those in the know speculate upwards of 2500ft lbs being the limit. Currently I have one customer putting nearly 2400hp and 2000ftlbs through one of these and all appears well. Looking for some ¼ mile 7's in a 5600lb truck is not a small feat!
I can ship a variety of ways. LTL along side a custom transmission or oversize 25×25×15 FedEx/UPS ground service. It’s 80lbs and is shipped dry. You must add 1.5qts of Dexron 3 or equivalent ATF fluid. Do Not Run Straight Tractor Oil! The majority of wear and failure comes from a lack of cooling oil. I am working with a program in Oklahoma to add an external pump and cooler. If the viscous coupler is not immersed in oil, it quickly overheats and all front wheel drive power is lost.
Due to the lack of decent cores in my local area, I’ve had to add $100 core fee as tracking them down has proved difficult.
As stated above its fairly heavy so shipping with full insurance will run toward $125 to go cross country with Fed Ex/UPS ground
if the stock is zero, please email me directly douglassproston@gmail.com for an ETA on restock. as of today November 13, 2025 I am backlogged 3 units without and cores on hand and am desperately searching for useable cores. I’m also being told the BMW nv125 case uses the same planetary so that may be a good source for you DIY guys wanting to build your own 6 pinion.
If you’re looking to make big power AWD in a medium to heavy weight car (—or more likely—truck) without breaking the bank, the new venture (later new process) 149 t-case is your box! After a few customers looking to go AWD pestered me into doing the research, I’ve found these beasts!
GM drivetrain hit another homerun selecting and specifying this unit. They combined simple operating principles with excellent metallurgy for another winner in toughness and longevity. The unique viscous coupler design is extremely robust and has a great 38/62 front/rear torque bias which then transfers more power front to rear as the weight transfers on a dig launch. from a roll, the 38/62 has a mild-yet-solid hit (gm calls it “the hump”) which keeps the vehicle stable even at speed. No computer controls needed. In fact these pair great behind a factory 4wd 4L80e as the 149 output has the 40T speed sensor most transmission control systems require but factory 4wd 4L80’s omit.
My upgrades to this unit include a billet 32spline input shaft from AMP drivetrain, oversize Borg Warner gears and chain from duramax spec np261xhd 1/2” wider than the factory 149 chain. I also update the output shaft bearing retainer and add a pump-rub prevention plate, eliminating the most common failure mode (case wear-through and complete lube oil loss)
I round out the unit with top shelf name brand roller and needle bearings.
GM rates these STOCK at 1900ft lbs and with my further upgrades those in the know speculate upwards of 2500ft lbs being the limit. Currently I have one customer putting nearly 2400hp and 2000ftlbs through one of these and all appears well. Looking for some ¼ mile 7's in a 5600lb truck is not a small feat!
I can ship a variety of ways. LTL along side a custom transmission or oversize 25×25×15 FedEx/UPS ground service. It’s 80lbs and is shipped dry. You must add 1.5qts of Dexron 3 or equivalent ATF fluid. Do Not Run Straight Tractor Oil! The majority of wear and failure comes from a lack of cooling oil. I am working with a program in Oklahoma to add an external pump and cooler. If the viscous coupler is not immersed in oil, it quickly overheats and all front wheel drive power is lost.
Due to the lack of decent cores in my local area, I’ve had to add $100 core fee as tracking them down has proved difficult.
As stated above its fairly heavy so shipping with full insurance will run toward $125 to go cross country with Fed Ex/UPS ground
if the stock is zero, please email me directly douglassproston@gmail.com for an ETA on restock. as of today November 13, 2025 I am backlogged 3 units without and cores on hand and am desperately searching for useable cores. I’m also being told the BMW nv125 case uses the same planetary so that may be a good source for you DIY guys wanting to build your own 6 pinion.
