SpeedFactory Racing FWD2AWD B-Series Gear Conversion Kit
The SpeedFactory Racing FWD2AWD B-Series Gear Conversion Kit has been created to provide you with the parts and modifications needed to easily retrofit a stock layout FWD B-Series gear set into your B AWD transmission with NO MACHINE WORK required!
Detailed instructions are included, and we recommend checking out our FWD2AWD YouTube Video for an in-depth install with component explanations.
Why would you want to do this?
- The B AWD factory ratios were designed for a heavy SUV with a low 6.3k-6.7k rpm rev limit and feature a super short 1st gear which does not work well with high revving high performance applications and creates major shifting difficulties due to the huge ratio spread on the 1/2 shift.
- The stock B AWD 1/2 shift forks are very thin and weak, often bending even in stock transmissions and are too thin for use with a FWD 1/2 slider.
- B AWD specific gear set options are very limited and retrofitting other oem gears used to require tedious machine work and custom spacer machining.
This kit now eliminates any need for machine work and opens your ratio options up to use almost any existing B-Series FWD gear set (either synchro or dog engagement that uses a factory style layout) and at the same time fixes the weak 1/2 shift fork issue by replacing it with a new much thicker and stronger billet fork!
1. Billet SFR 1/2 Shift Fork Conversion Service (Requires customer-supplied B-Series AWD 1/2 shift fork core to be sent to us) - Our hardened & shot peened billet steel retrofit upgrade is super strong and has the proper fork pad thickness to work with a FWD 1/2 slider.
2. Custom SFR 1st Idler Gear Split Needle Bearing - Previously if you wanted to attempt this conversion you had to machine the ID of the 1st gear larger or machine the countershaft journal height larger. With this custom bearing no machining is necessary!
3. Custom SFR Precision Spacers – Needed to achieve proper component locations
- Mainshaft Spacer (replaces the oem flat washer under the mainshaft - retain the flex washer underneath and set endplay to factory specs)
- 1/2 Hub Spacer (goes under the 1/2 slider hub)
- Reverse Thrust Washer (goes under the reverse idler gear if you are using a short 41.9mm tall FWD 3.0 ratio idler gear. If you have a 45.8mm tall FWD or AWD 3.0 ratio reverse idler gear you do not need to use this washer)
- Upper Cuff Shim (For use with Albins B Dog Set only, not used for synchro sets)
NOTE: You will need to use the gears, hubs, sliders, and synchros from the FWD sets and the pinion shaft and ring gear will still need to be an AWD specific set – either OEM or OEM compatible aftermarket final drive set. (Note: The B AWD 2nd synchro & 3rd/4th hub/slider/synchros can also be used.)
After you purchase this kit, please send your stock, unmodified B AWD 1/2 Shift Fork along with your contact information and order # to:SpeedFactory Racing
5001 S Burlington Way Suite A
Tacoma, WA 98409 NOTE: DO NOT SEND IN A FORK THAT HAS BEEN PREVIOUSLY MODIFIED OR HAD BRACES WELDED ON, WE WILL NOT USE IT.
What Do You Recommend for Synchro Sets?
For a super strong and street-able synchro set we recommend using the Albins Helical B Synchro set.
If you simply want the ability to run different ratios and don’t need the strength of a high quality aftermarket gearset, then the factory B16/ITR/GSR type gearsets will now be an option for you. We do not recommend using LS gearsets. Although the 1/2 are the same ratio as GSR, it lacks the dual-cone synchro on 2nd gear and will not work well for a high rpm/fast shifting performance application. LS 3/4 gears are not compatible as they use a smaller 54mm synchronizer.
What About Dog Sets?
For race car use we recommend the Albins 1-4 Helical B Dog set with Upper Cuff that we have used reliably for the last decade on our own record setting race cars.
If you are using an Albins 1-4 Helical B Dog set with Upper Cuff with this conversion you will also need to have your 5/R shift fork diameter enlarged.
We have not tested any other brands of B FWD dog sets for fitment/compatibility with this conversion kit other than PPG B FWD Dog sets which are NOT compatible as they use a non-oem style layout on the pinion shaft. If your current dog set uses a pinion shaft that has factory style splines then it should be compatible, but we cannot guarantee that.
What About Final Drives?
You can choose to retain the short factory B AWD 4.562 final drive set or upgrade to an aftermarket B AWD specific final drive set that is compatible with OEM. We recommend the Albins B AWD Extreme Duty Final Drive Set.
5th Gear Shift Fork Options:
It is simplest to stick with the factory AWD 0.812 5th gear and its matching synchro hub/slider/rings, and this is by far the most popular 5th gear option.
If you really want to run a FWD 5th gear it is going to take quite a bit of work. Due to the larger diameter 54mm synchronizer ring used on the FWD 5th gears, you will need to enlarge the diameter and thicken the pads on the AWD 5/R shift fork. You will need to run the FWD synchro hub/slider/rings and slightly clearance the inside of the transmission case to clear the larger diameter slider, it will rub the case otherwise and hang up.
If you are using a FWD 1-4 Dog set with an upper cuff it will have a 5/R fork spacer that is FWD diameter and you will need to open up the diameter of the 5/R fork to fit as well.
NOTE: We no longer offer the 5/R fork conversion service due to lack of demand.
Frequently Asked Questions:
- Can you send me modified forks and then I’ll send you my cores back?
No. The forks you send will be modified and then sent back to you. Allow up to 2 weeks for processing.
- What about the 3/4 shift fork?
Your factory AWD 3/4 shift fork is the same thickness and diameter as the FWD sets and does not require any changes.
- I noticed that the FWD input shaft is a bit shorter than the AWD input shaft. Does the FWD input shaft not reach the pilot bearing?
The FWD mainshaft pilot snout still reaches over half way into the pilot bearing which is just fine and doesn’t cause any issues.
- What about the clutch spline length, I noticed that those are a bit different between FWD and AWD?
Although slightly different in length it works just fine with both single and multiplate clutches.
- Do you offer core used transmissions, gearsets, or other internal components?
Sorry, we do not offer used core parts.