V8 Level II
Dec 2008 STOTM Winner, 2008 Truck Of The Year
U.S. Military - Veteran
V8 Engine Swap
MTOTM Winner
RBV's on Boost
- Joined
- Apr 29, 2008
- Messages
- 331
- Reaction score
- 4
- Points
- 18
- Location
- Michigan
- Vehicle Year
- 2003
- Make / Model
- Ford
- Engine Size
- Supercharged 5.0L
- Transmission
- Automatic
When I started my V8 swap project, I was sure that I didn't want to use the single ratio, full time AWD transfer case that come stock in the AWD version of the 5.0L Explorer. I wanted to have a manually shifted, 2-speed, part time 4WD transfer case like the one that came as factory equipment in my Ranger.
An easy (but expensive) way would have been to get a $500+ kit from Advance Adapters to mate the 4R70W Explorer transmission to the stock Ranger case. The kit consists of a new extension housing and an adapter shaft that steps down from the 4R70W's 31 spline output shaft to match the smaller Ranger T/C input spline.
For my purposes, it seemed like a better idea to substitute a larger transfer case designed for the torque of a V8. Thanks to the guys on ExplorerForum who developed the BW4406 swap into their 5.0L Explorers :thumbsup: , I felt that I had the info I needed to use the larger T-case in my Ranger. So, I picked up a low miles manual Borg Warner 4406 case from a 2003 F150 4.2/4.6.
The 4406 bolts directly to the stock AWD Explorer 4R70W extension housing without modification but that's where the easy part ends. Swapping it into a Ranger adds a new dimension to the clearance issues.
First of all, near the transfer case, a Ranger frame is several inches narrower than a Gen2 Explorer frame. Add to that the fact that the 4406 transfer case is huge compared to either the stock Ranger 2-speed case or the stock Explorer AWD case. It is nearly twice as long front to back and the main body sits about 4 inches rearward of where the main body of the Ranger case was. It is also much wider and would be positioned about 1/4" from the DS frame rail if the stock 5.0L Ex mounts were used. Even worse, the forward U-joint of the rear driveshaft would end up being about a foot farther rearward as compared to the stock Ranger, putting it adjacent and very close to the nose of the fuel tank.
The solution to both clearance problems was to move the entire engine/transmission/transfer case 3/8" toward the passenger side. This was accomplished by welding up the engine plate holes and trans crossmember holes and repositioning them.
These photos show the results of using the modified mounts. There is still not a lot of room but imagine how it would be using the stock mounting position - 3/8" closer!
Transfer case to frame rail clearance:
Slip yoke flange to fuel tank clearance:
This is the modified 97~03 F150 shift linkage mounted to the Explorer transmission extension housing. To get some extra clearance, I reversed and rewelded a pin in the linkage and cut almost 3/4" off the factory mounting bosses on the extension housing. Then I drilled the holes deeper and retapped the 14mm threaded holes for 5/8" x 1 1/4" NC bolts. This mod improved the clearance from the F150 T-case linkage to the smaller Ranger transmission tunnel. Combined with the 3/8" powertrain offset, the shortened bosses move the linkage and lever significantly inward on the transmission tunnel, keeping it from intruding any more than necessary into the driver's legroom.
Here is the 03 F150 silicone inner boot that has been reshaped to fit the Ranger tunnel. The stock Level II shift arm was too short by itself, so I made up an intermediate extension shaft from a piece of 3/4" drill rod.
F150 interior trim boot.
The shifter moved all the way rearward to the 4x4 Low position.
Center console from a junked 97 Mountaineer. It has been repainted satin black to match the rest of the interior. I repaired the broken console lid, then recovered it with black Naugahyde to match the newly painted console.
The lower driver side of the console was heated and reshaped to clear the shifter boot and bezel.
Shortened Ranger rear shaft and factory 97~03 F150 front shaft:
The internal factory Ranger slip yoke was cut off and a new fixed yoke welded in by a driveshaft specialist company. Then a 2006 Expedition/Navigator slip yoke was added before the assembly was balanced. The genuine Ford yoke is the right size for the F150 BW4406 transfer case and it was only $19 brand new on eBay.
A conversion U-joint is used to match the F150 front driveshaft to the stock pinion flange on the D35 front diff.
This conversion works great. The 4406 fits well, shifts well and has the strength to handle the torque of my blown small block. Even the stock Ranger 4x4 dash indicator lights work after wiring them to the switch on the 4406.
Everything combined - the shift linkage, conversion u-joint, slip yoke, j/y 4406 transfer case, j/y F150 front shaft and shortening of the Ranger rear shaft cost less then the AA conversion parts would have.
More info HERE.
Alternatives:
I chose the BW4406 because it is readily available, not too expensive and there are still some low mileage examples out there. Of course, there are many other F/S t-cases that can be used with a V8 swap. Ford, GM and Chrysler cases often use the same 6-bolt pattern to the transmission.
The main cases of the Borg-Warner 4407 T/C look to be about the same size as the 4406 but the 4407 has a fixed yoke output instead of the large rear slip yoke housing that my 4406 has. This might help in RBV's with shorter wheelbases or tank clearance issues. From what I've been able to find out, the 4407 was used on F250-up and junkyard 4407s are generally harder to find and more expensive than the 4406s.
There are smaller F/S cases that might make installation easier. A few possibilities are the NP205, NP208 and Dana 20. Since some are from earlier trucks, they might be a little harder to find and may be more likely to need a rebuild.
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