Dana 20 4-Wheel Drive Transfer Case Manual

8/12/2019 Dana 20 4-Wheel Drive Transfer Case Manual

1/14

ana 20 4-Wheel Drive Transfer Case Manual

ditors Preface:

und this document as a series of scans (of Ford Motor Company documents) on the Internet and am of the belief that the documents are i

blic domain. The images included in this text are cropped versions of the original scans, and have been cleaned-up for brightness and con

ng Optical Character Recognition software, I have converted the text from images to formatted html text.

e reader should realize that this manual covers the earlier T-Shifttype Dana model 20 transfer case. The later J-Shifttype transfer case

es slightly in construction and operation. I have used this manual as a guide in the disassembly and reassembly of my J-Shiftcase, and

gun to make notes where the two case types differ. I have not integrated these differences into written form as of yet, but plan to do so in t

ar future. I also realize that the text incorporated in the images may be fuzzy or hard to read, and I plan to fix this using image editing softw

eck back for further updates.

uglas Bohn - 27 November 2002

pdate Schedule:

04-2002 I reworked most of the illustrations by cutting out the blurry text, and adding new text to hopefully make them more readable.

29-2002 - I have added my comments on the disassembly of my J-Shift case. These comments are placed in the disassembly narrative in

per order, and are distinguished with a heavier, red italic text, such as:

di tors Note: Samp le of J-Shift addend a, blah blah b lah...]

ART 6-3 - 4-Wheel Drive Transfer Case

- DESCRIPTION AND OPERATION

manually shifted 2-speed transfercase in the 4-wheel drive Bronco

ontrols the power from the engine and transmission to the front and

ar driving axles (Fig. 1). The transfer case shift lever positions, from

ont to rear, are 4L (low gear, all wheels), N (Neutral), 2H (high gear,

ar wheels), and 4H (high gear, all wheels).

OWER FLOW - NEUTRALOSITION

When the transfer case gears are in neutral (Fig. 1), power from the

ont main transmission drives the transfer case input shaft and drive

ear. The drive gear drives the idler shaft and the high-speed gear

at free-runs on the front output shaft. Therefore, no power can be

elivered to either the front, or rear axle, even when the front main

ansmission is in gear.

ttp://www.classicbroncos.com/dana20/dana_20_manual.htm(1 of 14) [10/7/2007 8:52:41 AM]


2/14


OWER FLOW4L POSITIONLOW GEAR, ALL WHEELS)

When the transfer case shift lever is shifted into the 4-wheel low

osition, it pushes the two sliding gears back into engagement with

e idler shaft low-speed gear teeth.

he power flows from the main drive gear to the idler drive gear and

aft, and to the idler low-speed gear. From the low-speed, the powerws through the two sliding gears to their respective output shafts to

ve speed reduction.

OWER FLOW2H POSITIONHIGH GEAR, REAR-WHEELS)

When the transfer case shift lever is shifted into the 2-wheel high

osition, the two sliding gears are pulled forward out of engagement

om the idler shaft low-speed gear, leaving the front output sliding

ear in neutral and pulling the rear output sliding gear farther forward

o engagement with the clutch teeth of the main drive gear. Thiscks the main input shaft directly to the rear wheel output shaft.

he power flows directly from the transmission to the rear axle without

ny reduction of speed.

he front output sliding gear remains in a neutral position, the idler

aft drive gear turns the high-speed gear free on the front output

aft, and there is no power to the front axle.

Figure 1 Transfer Case Gear Train in Ne

OWER FLOW4H POSITION (HIGH GEAR, ALL WHEELS)

When the transfer case shift lever is shifted into the 4-wheel high position, it pulls the rear output and front output sliding gears forward into engagement wiutch teeth of the main drive gears. This locks the rear output shaft directly to the main input shaft, and the front output shaft to the high-speed idler shaft g

he power from the transmission flows from the drive gear in two directions. Direct drive to the rear axle flows through the rear output shaft. Direct drive to

ont axle flows through the idler shaft drive gear, high-speed gear, and front output shaft.

- REMOVAL AND INSTALLATION

EMOVAL



3/14


Raise the vehicle on a hoist.

Support the transfer case shield with a jack and remove the bolts

at attach the shield to the frame side rails. Remove the shield.

Drain the transmission and transfer case lubricant.

Disconnect the front and rear drive shafts at the transfer case (Fig.

.

Disconnect the speedometer cable at the transfer case.

Disconnect the shift rods from the transmission shift levers. Then,

ace the first-reverse gearshift lever into the first gear position, and

sert the fabricated tool (Fig. 2). This tool will prevent the input shaft

ler bearings from dropping into the transmission case when

eparating the transfer case from the transmission and output shaft.

Cut the lock wire and remove the two bolts, washers, plates, and

sulators that secure the crossmember to the transfer case adapter.

Remove the crossmember-to-frame side support attaching bolts.

Raise the transmission and remove the upper insulators from the

ossmember. Remove the crossmember.

0. Disconnect the shift rod from the transfer case shift lever bracket.

. Remove the bolt that attaches the shift lever bracket to the

ansfer case adapter, and allow the assembly to hang by the shift

ver.

2. Secure the transfer case to a transmission jack, and remove the

ansfer case-to-transmission attaching bolts.

3. Move the transfer case and jack rearward until it clears the

ansmission output shaft (Fig. 2). Lower the transfer case.

Figure 2 Removin g or Instal l ing Transfer C

NSTALLATION



4/14


Position the transfer case to the transmission (Fig. 2) and install the attaching bolts. Torque the bolts to specifications.

Position the shift lever to the transfer case adapter, and install the attaching bolt.

Connect the shift rod to the shift lever bracket and secure with the spring washer, flat washer, and cotter pin.

Raise the transmission and transfer case high enough to provide clearance for installing the crossmember. Position the upper insulators to the crossmem

nd install the cross-member-to-frame side support attaching bolts.

Align the bolt holes in the transfer case adapter with those in the crossmember, then lower the transmission and remove the jack.

Install the crossmember-to-transfer case adapter bolts, insulators, plates, and washers. Secure the bolts with lock wire.

Remove the fabricated tool, and connect each shift rod to its respective lever on the transmission with a spring washer, flat washer, and cotter pin.

Connect the speedometer cable.

Install the rear axle drive shaft to the transfer case, and torque the attaching bolts to specifications.

0. Install the front wheel drive shaft to the transfer case, and torque the attaching bolts to specifications.

. Fill the transmission and transfer case to the proper levels with the recommended lubricant.

2. Position the transfer case shield to the frame side rails, and install the attaching bolts.

- MAJOR REPAIR OPERATIONS

ISASSEMBLY

Clean the dirt from the transfer case, and

move the bottom cover plate.

Remove the retaining plug, flat washer, detent

pring, and ball that engage the front drive shift

l detent rod. Then, remove the plug from the

ont drive detent rod access hole (Fig. 3)

Remove the retaining plug, detent spring, and

all that engage the rear drive shift rail detent rod

ig. 3).

Remove the idler shaft Lock plate from the

ar of the case.

Using a hammer and soft drift, drive the idler

aft rearward and out of the case. Then, lift the

rust washers and idler gear from the case (Fig.

When removing the idler gear, do not lose

ny of the rollers.

Figure 3 Front and Rear Drive Shift Rail Detent Balls, Springs, and P



5/14


Remove the flange retaining nuts from the

ont and rear output shafts (Fig. 5).

Remove the flange from the front and rear

utput shafts (Fig. 6). Discard the front flange 0-

g.

Remove the bolts securing the adapter

ousing to the case and remove the adapter as

n assembly (Fig. 7).

A. [Editors note: Wi th m y J-Shi f t

ase, I found that I cou ld remove the

dapter hous ing, but that the input

haf t c luster was press- f i t in to the

ain case. If th is is the si tuat ion wi th

our J -Shi f t case, do not worry. Dont

t tempt to p ry the cluster out,

ecause you could damage the

achined surfaces. Simply remove

e adapter hous ing and proceed to

ep 9. You wil l remov e the input

haf t assembly in step 9A]

Remove the bolts that attach the rear output

aft bearing retainer to the case, and remove

e retainer and output shaft as an assembly. Be

areful not to lose any of the rollers.

A. If, in step 8 or 8A you were only

b le to remove the adapter ho using,

ue to the press f i t of the inpu t shaft

ssembly, note that now that the rear

utput s haft assembly is removed,

ou have access through the m ain

ase to LIGHTLY tap the input shaft

ssembly out of i ts press f i t wi th so ft

wood , plastic, brass) dri ft . Set the

put shaft assembly to the side wi th

s adapter housing .

0. Disconnect the shift rail link from the two shift

ls.

J-Shift Case own ers do no t need to

o th is since the i r ra i ls are not

ctua l ly connected tog ether)

. Lift the rear output shaft sliding gear from the

ase (Fig. 7).

2. Remove the setscrew securing the rear shift

rk to the shift fork to the shift rail. Then, remove

e rear drive shift rail and fork from the case

ig. 7).

Edi tors note: In order for the sl id ing

Figure 4 Removin g Idler S



6/14


ear to be removed from the shi f t

rk , the fork m ust be able to rotate

l the way over to the insp ect ion

or t . In m y case th is was no t an

pt ion, s ince the shi f t fork stopped

hort of the inspect ion port . I so lved

e problem as d escr ibed in step 12A

elow]

2A. Note that the rear drive shift

rk is secured to i ts shi f t ra i l by

eans o f a sunken, Al len head set

crew. This setscrew could be

emo ved with a 3/16Al len key, but

is could prove ted ious since there

l imited c learance, and the Al len

ey only affords 6 pos i t ions of grab.

h is inconvenience can be worked

round u sing a 1/4-hex-drive Al len-

pe bi t the type of b i t that m ight be

und in a universa l screwdr iver type

ol set. Inset the (3/16size) bit into

e setscrew . A 12-pointed 1/4" b ox

nd wrench may now be used to turn

e Al len bi t , removing the setscrew.

he 12-poin t wrench affords m ore

ersati l i ty than a 6-point wrenc h

ecause of i ts in-between

crements. Do not back the

etscrew out ent i rely just enough

free the shi f t fork from the shi f t

a i l. Once the shi f t fork is unsecured

om the shi f t ra i l, the fork can swing

eely on the rai l and the sl idin g gear

an be removed through the

spect ion port . Once the gear isemoved, sl ide the shi f t ra i l out from

e shi f t fork and ou t of the case.

emove the shi f t fork from the case.

3. Remove the front output shaft rear cover and

ims. Tie the shims together.

4. Remove the front output shaft bearing

tainer and gasket. Remove the retainer seal if it

worn or damaged.

5. Tap the threaded end of the front output shaft

remove the rear bearing cup from the case

ore.

6. Wedge the front output shaft front bearing

way from the main drive gear to allow removal

the snap ring from its groove in the shaft.

hen, tap the shaft and rear bearing out of the

ase (Fig. 8).

Edi tors no te: Your J-sh i f t case MAY

Figure 5Removing o r

Instal l ing Flange

Retaining NutFigure 6 Removing Fl

Figure 7 Removing or Insta l ling A dapter Hou



7/14


OT have the aforemention ed c-cl ip

n the front dr ive output sh aft in

etween the bearing cone and the

gh speed drive gear. If not, not e

at the front bear ing co ne is mi ld ly

ressed onto the shaft at the spl ined

rea. You are able to CAREFULLY

wi th a l ight hammer and a soft dr i f t )

p the shaft assembly toward the

ear of the case, driving the front

earing con e off the shaft. You canow rem ove the shaft assembly.

7. Lift the sliding gear, main drive gear, front

earing, spacer, and snap ring from the case.

8. Remove the front cup from the case bore.

9. Remove the setscrew securing the front shift

rk to the shift rail. Then, remove the shift rail

nd fork from the case.

0. Remove the detent rods (Fig. 9).

0A. With the later J-Shift case, you

ay n ot ice that there is on ly ONE

etent ro d (Figures 9 and 18). While

ere may be debate over th e

xis tence of o ne or tw o rods , severa l

Shift case owners have reported

at they have only on e rod. This

ngle rod wi l l be remov ed from the

ug hole at the rear of the left side,

assing through to the sing le r ight-

and plughole.

Figure 8 Removing Front Outpu t Shaft

Figure 9 Removing Detent R

ARTS REPAIR OR REPLACEMENT



8/14


NPUT SHAFT

Remove the snap ring from the front of the shaft (Fig. 10).

Place the adapter housing and input shaft on a press, and

ess the shaft out of the main drive gear and housing.

Remove the bearing retaining snap ring from the housing

ore, and remove the bearing.

Remove the seal in the adapter housing if it is worn or

amaged.

If the adapter housing seal was removed, install a new seal

th the tool shown in Fig. 11.

Place the bearing in the housing and secure with the snap

g.

Using the main drive gear as a base, press the input shaftrough the housing, seal, bearings, and main drive gear.

stall the snap ring on the front of the shaft.

REAR DRIVE OUTPUT SHAFT

Remove the needle bearings from the bore of the shaft

ig. 12).

Remove the speedometer driven gear from the bearing

tainer housing.

Place the bearing retainer and rear output shaft assembly

a press, and press the shaft out of the retainer.

Lift the speedometer drive gear and shims. from the shaft

ig. 12). Tie the shims together.

Press the outer cup, bearing and seal from the bearing

tainer as shown in Fig. 13.

Remove the inner cup with the tool shown in Fig. 13.

Remove the inner bearing from the output shaft with the

ol shown in Fig. 14.

Press the shaft onto the inner bearing with the tool shown

Fig. 14.

Install the outer cup in the bearing retainer with tool T55P-

6l6Al.

0. Install the inner cup with tool T56T-461 6-A2.

Figu re 10 Input Shaft, Disassem

Figure 11 Instal l ing A da

Housin g



9/14


. Position the outer bearing into the bearing retainer. Then,

ace the shims and speedometer drive gear on the output

aft, and install the shaft in the bearing retainer housing.

2. Place the bearing retainer and shaft in a vise. Install the

utput shaft flange and torque the retaining nut to

pecifications. Install a dial indicator on the flange end of the

utput shaft, and check the end play. The end play should be

003-0.005 inch. If not within these limits, adjust the shim

ack (Fig. 12) between the speedometer drive gear and rearutput shaft outer bearing.

3. After establishing the correct end play, remove the output

aft flange and press the bearing retainer seal in the housing

th tool T56T-46 16-A. Install the speedometer driven gear.

RONT DRIVE OUTPUT SHAFT

To remove the front output shaft rear bearing, use the

ding gear as a base and press the bearing from the shaft.

Install the bearing as shown in Fig. 15.

HIFT RAIL OIL SEALS

Remove the shift rail seals as shown in Fig. 16.

Install the two shift rail oil seals, using the tool shown in

g. 17.

Figu re 12 Rear Drive Output Shaft, Disassem

Figure 13 Remo ving Rear Bea

Retainer Ou ter Cup, B earing, and



10/14


Figu re 14 Replacing Outpu t Shaft Inner Bea

Figu re 15 Insta ll ing Front Ou

Shaft Rear Bea



11/14


Figure 16Remov ing Shif t Rail Seals Figure 17 Insta

Shift Rail Oil S

SSEMBLY

Install the front detent rod in the case.

Slide the front drive shift rail all the way into the case, and position

e shift fork on the rail as the rail goes into the case. Secure the fork

the rail with the setscrew.

Position the front output shaft sliding gear in the shift fork.

Install the rear detent rod in the case.

Slide the rear drive shift rail into the case, and position the shift fork

the rail as the rail goes into the case. Secure the fork to the rail with

e setscrew. The shift rails should be inserted so that the detents are

sitioned as shown in Fig. 18.

While holding the sliding gear and main drive gear in position, install

e front output shaft and rear bearing assembly through the two gears

m the rear of the case.

Install the main drive gear spacer and secure with the snap ring (Fig.

).

Install the front output shaft rear bearing cup.

Position the front output shaft rear cover and shims to the case, and

stall the attaching bolts.

. Using front flange and the tool shown in Fig. 5, install the fronttput shaft front bearing on the shaft. Install the front bearing cup

g. 19).

. If the front bearing retainer oil seal was removed, install a new seal

using tool T57-L7657. Position the bearing retainer and gasket to

e case, and install the attaching bolts.

. Place the rear output shaft rear bearing retainer on a workbench,

d install 13 needle bearings in the splined hub of the output shaft

th Vaseline or grease.

Figu re 18 Shift Mecha

Figu re 19 Front Outp ut Shaft, Disassem



12/14


. Position the rear output shaft rear bearing retainer assembly to the

se and install the attaching bolts.

. Install the rear output shaft sliding gear in the shifting fork and on

e splines of the output shaft.

. Position the adapter housing assembly to the rear output shaft and

se. Install the attaching bolts (Fig. 7)

. Install the roller bearings in the bore of the idler shaft gear with

se-line or grease.

. Position the idler gear and thrust washers in the case, and drive

e idler shaft into the rear of the case through the idler gear and thrust

ashers. After installing the idler shaft, tap the sides of the case to

ieve tension from the case. Install the idler shaft lock plate.

. Secure the shift rail link to the two shift rails.

. Install the front and rear drive shift rail detent balls, springs, and

taining plugs. Be sure that the heavier loaded spring and flat washer

e installed in the front drive shift rail. Install the rod access hole plug.

. Install the flange, washer, and retaining nut on each of the output

afts, using the tool shown in Fig. 5. Be sure to install a new 0-ring in

e front output shaft flange. Torque the attaching nuts to specifications.

. Install a dial indicator on the front drive output shaft and check the

d play as shown in Fig. 20. The end play should be 0.003-0.005

ch. If not within these limits, adjust the shim pack at the front output

aft rear cover.

. Position the cover plate to the case and install the attaching bolts.

Figu re 20 Checking Front D

Outpu t Shaft End

ART 6-4 - Specifications

ECONOLINE

TRANSMISSION GEAR RATIO

Engine CID Ratios

1st 2nd Rev.

170-IV 3.41 1.86 3.51

240-1V 2.99 1.75 3.17

302-2V 2.99 1.75 3.17

ADJUSTMENTS

APPROXIMATE LUBRICANT REFILL CAPACI

Transmission 3.5 Pints

TORQUE LIMITS

TRANSMISSION Ft-l

Input Shaft Gear Bearing Retainer to TransmissionCase

30-3

Transmission to Flywheel Housing 37-4

Transmission Cover to Transmission Case 14-1



13/14


TRANSMISSION

Detent Set Screw Head Flush to 0.020 inch below casesurface

End PlayReverse Idler 0.004-0.018 inch

End PlayCountershaft Gear 0.004-0.018 inch

BRONCO

TRANSMISSION GEAR RATIO

Engine C I D Ratios

1st 2nd Rev.

170-1V 3.41 1.86 3.51

289-2V 2.99 1.75 3.17

ADJUSTMENTS

TRANSMISSION

Detent Screw Head Flush to 0.020 inch Below casesurface

End Play-Reverse Idler 0.0040.018 inch

End Play-Countershaft gear 0.0040018 inch

TRANSFER CASE

Front Drive Output Shaft-End Play 0.003

0.005 inchRear Drive Output Shaft-End Play 0.0030.005 inch

TORQUE LIMITS

TRANSMISSION AND TRANSFER CASE Ft-Lbs.

Crossmember to Adapter Bolts 30-40

Transfer Case Adapter to Transmission Case Bolts 35-45

Crossmember to Side Support Bracket Nuts 40-60

Drive Shaft Flange to Transfer Case Output ShaftsNuts

125-150

Adapter to Transfer Case Bolts 25-35

Rear Output Shaft Bearing Retainer Bolts 25-35

Front Output Shaft Bearing Retainer Bolts 25-35

Transmission Control Bellcrank Pivot Bolt and Nut 35-45

Speedometer Cable Retainer to TransmissionExtension

3-4.

Transmission Extension to Transmission Case 42-5

Flywheel Housing to Engine 40-5

Gear Shift Lever to Cam & Shaft Assembly Lock Nuts 18-2

U-Joint Flange to Output Shaft 60-8

Filler Plug 10-2

Drain Plug 20-3Shifter Fork Set Screw 10-1

APPROXIMATE LUBRICANT REFILL CAPACI

US. Measure Imperial Measure

Transmission 3.50 Pints 3.0 Pints

Transfer Case 2.75 Pints 2.25 Pints

SPECIAL TOOLS

Tool Number Description

T50T-100-A Impact Hammer-Long

T59L.100-B Impact Hammer-Short

T58L-101-A Puller Attachment

T53L-200-A Handle Adapter-Female 1/213

T57L-4220-A4 Differential Bearing Assembly Remover

T53T-462-B Drive Pinion Bearing Cone Replacer-Frontand Rear

T57-L-4621-B Pinion Bearing Cone Replacer

4201-C Backlash and Runout Gauge

4851-K Universal Joint Flange Holder

T56L-4851-C Flange (Universal Joint) Axle End Remove

T52T-6500-DJD Reverse Shift Rail Pliers

T63P-7025-A Output Shaft Bearing Remove and Replac

T63P-7111-B Cluster Gear Roller Retainer Shaft

164 E-7052-B Extension Housing Oil Seal Replacer



14/14


Check outClassicBroncos.comfor all of your

Early Bronco needs
http://classicbroncos.com/http://classicbroncos.com/http://classicbroncos.com/

Documents

Dana 20 4-Wheel Drive Transfer Case Manual