We offer several transmission upgrades for the 1966-77 Ford Bronco. The information listed below offers both popular automatic and manual upgrades. This sections covers the following transmissions:
Manual transmission: AX15, NV3550, NV4500, TR4050, ZF, T18, NP435, T&C 4 speed
Automatic transmission: C4, C6, AOD, AODE (4R70W), 6R80, and GM transmissions 700R, TH400
Bronco Dana 20 Applications for the AX15 & NV3550:
These transmissions are ideal transmission swaps for the early Broncos. The weight of these 5 speeds is similar to the stock 3 & 4 speed transmissions. The overall size and length make it an ideal fit. The gearing of these 5 speeds is as follows:
AX15 is 1st 3.83:1; 2nd 2.33:1; 3rd 1.44:1; 4th 1.00:1; 5th 0.79:1, and Reverse 4.76:1.
NV3550 is 1st 4.01:1; 2nd 2.32:1; 3rd 1.40:1; 4th 1.00:1; 5th 0.78:1, and Reverse 3.57:1.
The transfer case adapters we manufacture for these transmissions use an adapter plate and spud shaft. The adapter plate offers two rotation options for the Dana 20 transfer case: the stock rotation which is 42 degrees and a higher rotation of 34 degrees. The higher rotation may require a body lift for proper clearance. The transfer case adapter comes with a transfer case shifter linkage bracket which only fits the “T” style shifter.
The stock Ford bellhousing will also need to be adapted. The NV3550 and the AX15 have a 7-1/2” long input shaft. We manufacture an adapter plate that bolts to the front of this transmission. This adapter provides you with the proper indexing and bolt pattern to couple to the stock bellhousing. When bolting to the NV3550, the stock bellhousing requires some slight modifications. The stock pressure plate and release bearing are retained and a new 1-1/8” 10 spline clutch disc is used.
The new crossmember for the NV3550/AX15 transmission must also be used. Since these 5 speeds do not offer the angular support pads, and our adapter is too short to have these provisions, we designed a new crossmember support for the new transmission. Our new crossmember bolts to the stock crossmember frame hole and includes a new rubber support. The crossmember is designed to fit both stock exhaust and header applications.
*P/N 50-9920A - AX15 to Bronco Dana 20 T/C adapter (1.40” long)
*P/N 712543 - AX15 to Ford bellhousing 4.848” index (adapter length 7/8”)
*P/N 383735 - 1-1/8” 10 spline clutch disc
*P/N 716000A - AX15 Crossmember support
P/N 27-3520AX15 - AX15 BRONCO DANA 20 KIT (*includes all parts listed above plus a shift handle)
P/N 27-3525 - AX15 TRANSMISSION & BRONCO DANA 20 (AX15 Transmission Included)
*P/N 50-9920 - NV3550 to Bronco Dana 20 T/C adapter (1.40” long)
*P/N 712544 - NV3550 to Ford bellhousing 4.848” index (includes clutch)
*P/N 716000 - NV3550 Crossmember support
P/N 27-3520AA - NV3550-BRONCO DANA 20 KIT (*includes all parts listed above plus a shift handle)
TR-4050 TRANSMISSION: (New Transmission)
TREMEC® TR-4050 Heavy Duty 5 speed O/D transmission for 4WD applications.
26-TR4050D DODGE INPUT SHAFT 23 SPLINE OUTPUT
Features: Ratios: 6.16, 3.11, 1.71, 1.00, .76 Rev. 6.03, 600 LB-FT @ 15,000 Lbs GCVW, Right side PTO - 6 Bolt. Chrysler/Jeep Transfer case bolt circle with 23 spline output shaft. Oil Capacity - 3.67 QT. High-contact constant mesh helical gears for maximum strength. Die-cast aluminum alloy housing saves weight while offering considerable rigidity. Standard right-hand six-bolt PTO offers ability to run hydraulic pumps. The multiple rail internal shifter provides excellent shift feel and performance. Tapered bearing on input, main and counter shafts provide excellent internal stability. Needle bearings under gears reduce friction and noise output. All forward gears and reverse gear synchronized. Advanced synchronizer technology promotes smoother shifting and reduced shift effort. Counter shaft mounted 5th gear synchronizer improves NVH in overdrive. Weighs 164 lbs, 19.5" overall length, .590"(GM) .750"(DODGE) Pilot diameter; 5.125"(GM), 5.60(DODGE) Index retainer diameter; 1.125" Input shaft diameter, 10 spline.
Bellhousing Adapters:
712551 - Adapter Plate to Ford bellhousing (Use 26-TR4050D)
Ford Bronco Dana 20 - The adapter for the Dana 20 is the same as we use for the NV4500, 50-0209. This kit offers a spud shaft that couples the 23 spline TR-4050 to the Dana 20.
T & C 4 speed:
This transmission has the same bolt pattern and is 1” longer than the stock 3 speed transmission. This conversion kit consists of a new output shaft, shift rod bushing, and gasket kit. The 9-3/8” stock adapter housing is used and some machining is required. Your stock tailhousing must be drilled and reamed for the shift rail. The counter bore on the adapter housing must be machined to accept the larger 307 bearing. This kit utilizes the stock Bronco spud shaft. This transmission is side shifted and will require additional shifter components. Floorboard modifications will be necessary for shifter clearance and driveshaft modifications may be required.
P/N 50-1900 - Ford T & C 4 speed to Bronco Dana 20
P/N 715503 - Hurst Competition Plus shifter bracket
P/N 715630 - Shifter rod kit
P/N 715600 - Hurst Competition Plus shifter & handle
ZF 5 Speed:
We offer an adapter and shaft assembly to adapt the Bronco Dana 20 transfer case to the ZF 4WD 5-speed transmission. This adapter kit is 1.50” long and comes with a new spud shaft and alignment retainer.
P/N 50-4303 - Ford ZF 5 speed to Bronco Dana 20 transfer case
Ford NP435 & T18:
These truck transmissions are a very popular choice for the early Bronco drivetrain. The kit includes an adapter housing, alignment retainer, seals and gaskets. The kit utilizes the stock 2WD transmission output shaft (28 spline) and the stock Bronco spud shaft. The adapter housing is drilled for both the NP435 & T18 transmissions. When installing the NP435 in a V8 application, this combination will not require any driveshaft modifications. The T18 is 1” longer than the NP435, requiring driveshaft modifications. Both trannys will require some floorboard and shift handle modifications.
P/N 50-2700 - NP435 & T18 to Bronco Dana 20 (adapter length of 7.500”, transmission 10.875”)
Dodge NV4500 5 speed:
The NV4500 was introduced in 1993 and has been recognized as the ultimate manual transmission of choice. With a 5.61:1 low gear ratio, 27% overdrive and a synchro-reverse, this transmission works well with the early Broncos. The adapters we manufacture only fit the Dodge gas version. The transfer case adapter is supplied with an adapter housing, a special spud shaft, and the necessary bearings and seals. Your Ford bellhousing will also need to be adapted. The Dodge NV4500 has a 7-1/2” long input shaft. We manufacture an adapter plate that bolts to the front of this transmission. This compensates for the long input shaft and provides the necessary Ford bellhousing bolt pattern. Another consideration is the clutch disc spline. The stock Ford is 1-1/16” 10 spline, and the NV4500 is 1-1/8” 10 spline; therefore, a new clutch disc will be required. When installing these components, driveline and floorboard modifications will be required.
P/N 50-0209 - Dodge 23 spl. NV4500 & TR-4050 to Bronco Dana 20 T/C adapter (adapter 7.300”, tranny 12.375”)
P/N 50-0230 - Dodge 29 spl. NV4500 to Bronco Dana 20 T/C adapter (adapter 7.300”, tranny 12.375”)
P/N 712551 - Dodge NV4500 & TR-4050 to Ford bellhousing 4.848” index (adapter length 7/8”)
P/N 383735 - 11” Centerforce clutch disc
P/N 716101-2 - Rubber crossmember mount
P/N 716000-4 - Crossmember support for the NV4500 & TR-4050
We offer a complete kit to use the Dodge NV4500 transmission. This assembly consists of a new transfer case adapter, transfer case linkage, crossmember mount, bellhousing or bellhousing adapter plate, clutch disc (on some applications), and shifter handle. This complete adapter package from us is a cost effective way to order.
P/N 27-0044T - Dodge NV4500 29 spl. transmission assembly to Ford Dana 20 O.A.L. 27.00”
C4:
3 speed automatic: Even though Ford used this transmission stock in vehicles from 1973-77, stock parts are no longer available. We manufacture a new aluminum adapter housing and a custom output shaft that is identical to the original Ford C4. This kit uses the stock Bronco spud shaft, which may need to be shortened in some applications. No driveline modifications are required when replacing a manual 3 speed that was originally mated to a V8. The automatic shifter can be obtained from either 1973-77 Bronco, or a B & M cable operated sport shifter can be used, P/N 715680.
P/N 50-4200 - C4 auto to Bronco Dana 20. Kit supplies a new casting & C4 main shaft, retaining the stock spud shaft.
P/N 50-4200A - C4 auto to Bronco Dana 20. Kit supplies a new casting, mainshaft and spud shaft in the kit.
(Both adapter kit lengths 7.375”, transmission 17.000”)
AOD & AODE:
This automatic overdrive transmission has become very popular among Bronco owners. The gear ratio found in this transmission is great for trail and highway use. We manufacture adapters for both AOD & AODE (4R70E) transmissions. This transmission assembly is 1-1/2” longer than the stock V8 assembly. It requires relocation and modifications to your stock crossmember. The “T” handle transfer case shifter is the easiest linkage to use, having only minor modifications. The “J” pattern can be used - but with a little ingenuity. The adapter kit comes complete with an adapter housing, main shaft, spud shaft, bearings and seals. Transmission length 20.375”.
P/N 50-2704 - All AOD (1980 & up) to Bronco Dana 20 (adapter length of 6.000”)
P/N 50-2704A - AOD 4WD to Bronco Dana 20 (adapter length of 7.400”)
P/N 50-2704E - AODE to Bronco Dana 20 (adapter length of 6.000”)
C6:
3 speed automatic: If you are installing a high horsepower V8 and want to use an automatic, this transmission is your best choice. The C6 tranny and adapter housing will be 2-1/2” longer than your factory setup. Driveline & crossmember modifications are necessary. The stock transfer case linkage will need minor modifications to fit on this adapter housing. This kit uses a stock 4WD C6 tailshaft with 31 splines. This kit also includes a new 8” adapter housing, spud shaft, and necessary bearings and seals. (Note: At one time, this kit included a custom C6 output shaft with 28 splines and used the stock spud shaft. This design was discontinued in 1998).
P/N 50-4301 - C6 to Bronco Dana 20 (adapter length of 8.000”, transmission 20.000”)
COYOTE V8 & 6R80 TRANSMISSIONS FOR BRONCOS:
The new Ford blocks 4.6, 5.0 & 5.4 have gained popularity for swapping into the early Broncos. We have designed a bellhousing system for the manual transmissions and a transfer case adapter for the 6R80 automatic transmission.
Ford 6R80 Automatic transmission: This newer automatic overdrive transmission is very popular choice for the Broncos. The gear ratio's starting out with a 4.17:1 and a double overdrive, this transmission is great for trail and highway use. We manufacture adapters for the 4WD version of this transmission. This transmission is 27" long and the adapters adds 4.625". It requires a new crossmember which we manufacture for this application. We currently do not have a transfer case linkage bracket, but check with us as one will be offered sometime in the future. The adapter kit comes complete with an adapter housing, spud shaft, bearings, bearing retainer and seals.
P/N 50-3901- 6R80 TO Bronco Dana 20 Adapter
P/N 50-3900- 6R80 TO Atlas T/C Adapter
P/N 716040 - Crossmember support for the 6R80
Bellhousing Adapter to Modular Ford “Coyote” Engine: This is a full Ford bellhousing that has been modified for a hydraulic clutch linkage. The bellhousing comes with the slave cylinder & bracket, clutch arm, pivot ball, starter index plate and crank bushing with a .750” I.D. This bellhousing has a 4.848” index and can be coupled to any early Ford transmission with a pilot bearing change or we suggest using it on a NV4500, or AX15. These transmissions along with the 1” adapters to make them look like a Ford are a perfect fit for these engines.
P/N 712546 - COYOTE 4.6 / 5.0 / 5.4 BELLHOUSING KIT W/ HYDRAULIC
GM TH400:
The kit includes two adapter housings, a main shaft, a spud shaft, and the necessary bearings and seals. Driveline and floorboard modifications are required.
P/N 50-3601 - TH400 to Bronco Dana 20
(adapter length of 2.250”, transmission 24.250”)
GM 700R:
This transmission conversion is becoming very popular. As mentioned above, the 700R is an ideal transmission for the Broncos. The 3.06:1 1st gear is great for rock crawling, and the .70:1 overdrive is excellent for mileage. The kit includes two adapter housings, a main shaft, a spud shaft, and the necessary bearings and seals. Driveline and floorboard modifications are required.
P/N 50-2706 - 700R to Bronco Dana 20 (adapter length of 2.500”)
GM Automatic transmission to Ford small blocks:
We offer an adapter plate and flywheel adapter to couple the GM automatics (TH350, TH400 & 700R) to the stock Ford engine. These adapters are 3/8” thick and provide an excellent way of combining the GM transmission into your Bronco. These kits have become very popular for the rock crawling enthusiast. It provides the ability to install the popular 700R transmission, which has a good reliable reputation and a great low 1st gear for an automatic.
P/N 712588-A GM Transmission to Ford 302 1968-80 (28 oz. balance)
P/N 712588-B GM Transmission to Ford 302 1982-97 (50 oz. balance)
P/N 712588-C GM Transmission to Ford 302 (no flexplate)