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 Dana 20 (Early Bronco 66-77 version) |
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Bronco Dana 20
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| 66-72 "T-handle shift" Bronco Dana 20. |
The 66-77 Ford Bronco used a version of the Dana 20. It is NOT interchangeable with the jeep unit. It had a different bolt pattern, it had a left drop instead of a right drop, different gear ratios, etc
It is also useful in Klune projects in Wranglers, as it is only 12" long, and has the needed left drop
Using the Klune with a Bronco Dana 20
We carry a kit to mate a Klune to this Tcase with a 1" thick adapter. See: Hercules: Klune-V / Bronco 20 combo
Transfer Case Specifications:
Transfer Case Overall Length : 10.75”
(measured from bolt-up surface to U-joint center in rear yoke)
Bronco Dana 20: 1966-1972
These cases had a 2.46:1 low range.
Bronco Dana 20: 1973-1977
These cases had a 2:34:1 Low range.
Single and Twin stick applications
Bronco Dana 20: 1966-1972
The shift mechanism has a bar between the two shift rails, which a single shift rod connects to a shifter that works in a straight line pattern 4Hi - 2Hi - N - 4L. This Tcase will shift directly from a Wrangler type Tcase shifter by use of a single rod.
These cases can be twin-sticked by dis-assembling the case and removing an interlock pin in the shift rail mechanism. A twin stick shifter handle assembly will be needed.
Bronco Dana 20: 1973-1977
The shift mechanism has two rails protruding from the front of the case which have welded on tabs designed to interface with the stock J pattern shifter. This "J" shifter mechanism works only with the stock type Bronco Tcase adapter housing. In other than stock applications, it is usually easiest to convert to twin sticks.
Twin Sticking: This transfer case requires no internal modification to work with twin sticks to get front wheel drive, rear wheel drive or 4 wheel drive in any range. It is easily modified for twin stick use without any internal modification to the Tcase:
Wild Horse Twins stick kit for 73-77 Dana 20
The Wild Horses system will place the twin sticks just in front of the Tcase. It works using the stock, unmodified tabs on the 73-77 Bronco Dana 20 shift rails. They supply several different packages configurations are available. This may not work with non-stock trasnfer case adapters. Check with Wild Horses.
Other Jeep Trannies: This kit looks like it will work with most any Jeep trans from 1980-up, perhaps with no modification, or some light massaging. We have not actually done this, (and neither has WH, they work on Broncos!, not Jeeps:-) but it sure looks that way
Fits NV4500 using Bronco 20 $182
(Prices at the time of this writing Mar 05. We are happy to supply any of these WH components as a part of one of our package systems)
Atlas II twin stick shifter: We have been using the shifters made for the Atlas II in some installations. While these obviously will not bolt up directly to a Bronco Dana 20, (they were designed for an Atlas), a mounting bracket for the shifters must be fabricated from the transmission tailhousing. (Make this bracket strong so it won't bend when you have to pull hard on the shift levers) This bracket would then provide a base to mount the Atlas shifter mechanism to the trans tailhousing, crossmember or vehicle body. This set up works well in moving the shifter setup well forward of the Tcase, desirable with longer transmissions or Klune Underdrive installations.
Diagram: Atlas Twin Stick (This is the drawing from the Atlas Manual, as used on an Atlas)
Mounting the Twin Stick forward of the Tcase, and linking by linkage rods requires modification to the shift rails:
"J" Pattern rails shown marked for cutting in 1st photo, shown cut and drilled for twin stick linkage rods in second photo. Some 3/8 all thread and a couple heim joints makes nice linkage rods. You need 3/8 Heim joints to work with the atlas shifter, but the rods are too small to drill 3/8. We drilled 3/16, and used a small bushing to fit a 3/16 bolt in a 3/8 Heim. Use a nylock nut so the thing doesn't vibrate off on the trail.
32 spline output kit for the Bronco 20
The stock Bronco 10 spline output shaft will hold up for reasonable use with up to a stock small block V8 or 35" Tires. Extreme abuse or larger engine/tires should consider upgrading the output shaft to 32 spl. This heavy duty output shaft is basically the same super stout unit used in the rear of the Atlas. It will accept 1310 CV Yoke (standard) , as well as (Optional) 1310 non CV yoke, 1350 Yoke and 1350/1410 Flange style.
Note: There are two versions of this kit. Both are the same price ($399)
One version uses a new tailhousing casting. is ready to bolt up in place of the stock output. this output housing and shaft are 1-1/4" longer than the stock output. With this kit, the overall length of the unit is 19.75". The second version is a 32 spl output shaft that fits the stock Bronco output housing. Due to the larger size yoke, it is 3/4" longer than stock.
Jeep VSS/speedo connection
With the Stock Bronco 20 T-Case Output:
If you have a mechanical speedometer (Jeeps about 1991 and earlier), you will simply need to use a 10" speedo adapter cable built using with the fitting to go into the Bronco Dana 20 and the speedo gear on one end (66-77Bronco, "Ford Bulb Type w stock Ford speedo gear) (different number of teeth available for different axle ratio calibration), and set up to couple to the stock Jeep (or whatever) speedo cable on the other. Just like in a Jeep, you can swap out different gears to calibrate the speedo. Any local speedo shop should be able to make such a cable. I bought mine from:
North Hollywood Speedometer (818)761-5136
Jeep VSS Adapter to Bronco 20 Tcase:
This makes a very clean, simple, low cost connection form your stock Jeep VSS to the Bronco 20 Tcase
Take your stock Jeep VSS. Separate the actual VSS portion from the gear holder portion of the housing. Remove the gear (it pulls out). Take a hacksaw and notch the end of this housing (where the gear came out of) .500 deep.
Build a short cable, Ford bulb & gear on one end, about 12” long. Other end is plain jacket with ¾” bare cable sticking out. A coupler is swaged to this cable stub which will accept a .104 square male speedo sensor drive. The .290 OD cable jacket is enlarged to.370 using tape or heat shrink tubing. This cable is available from North Hollywood speedometer for $29.
North Hollywood Speedometer (818)761-5136
This cable assembly fits into a .375 dia opening in the bottom of the VSS plastic housing where you notched it. The cable coupler with the coupler coupling to the VSS drives shaft inside. The plastic housing (where it was notched can be tightened down onto the cable using a hose clamp.