Trail Creeper 4.70 T-Case Gear Kit
Install Instructions
 

Tools Required:
  • Ratchet, 12mm, 14mm, and 30mm sockets
  • Air Wrench
  • Needle Nose Pliers
  • Hammer
  • Grinder
  • 3/16 Diameter Pin Punch
  • Snap Ring Pliers
  • 6mm Allen Wrench
  • Gasket Scraper
  • Flat Blade Screwdriver
  • Adjustable Wrench
  • Permatex Ultra Gray Silicon
  • Axle Grease

 

 

4.70 Gear Kit Parts List

23 or 21 Spline input gear w/bearing pressed on
4.70 Low range gear
Counter shaft gear w/bearing pressed on
Transmission output seal
Rear output seal
Front output seal w/felt and retainer
Shift fork clip
Drain and fill plug gaskets
Complete gasket set

 

 

 

 

 

What is the difference between 21 and 23 spline gears?

The transfer case input gear is the gear that slides in to the transmission. V6 and Turbo transmission use a 23 spline gear that is slightly larger then the 21 spline gear used on 4cyl transmissions. On a single transfer case you must use the gear type that matches the transmission.

If you are building a dual transfer case assembly, the front case input gear must match the transmission output gear. The rear case of a dual transfer case can be set up with either 21 or 23 spline gears. When purchasing a dual transfer case adapter you can choose to purchase a 21 or 23 spline version. The only difference between a 21 and 23 spline dual adapter is the coupler that connects the front and rear case. It is important to match the dual adapter and rear gear set. If your rear case is going to run the stronger 23 spline gears you must also run a 23 dual adapter coupler. If your rear case is going to use 21 spline gears then the dual adapter coupler must also be 21 spline.

In a dual transfer case with 21 spline gears in both cases the weak spot and most common failure point is the input gear to the rear case. A dual transfer case built with 21 spline gears in the front case and 23 spline gears in the rear case is stronger and now the most likely point of failure becomes the rear output shaft. If your purchasing both a dual adapter and 4.70 gears for the rear case, order both in 23 spline. There is no cost difference building with 23 spline parts if you order both the dual adapter and gears in 23 spline configurations.

If you have questions about setting up your gears or dual adapter, please call us at 559-252-4950.


 In these instructions we refer to different transfer case housing sections by number. The photo above shows each of the housings and its number.

 

 


 Step 1: Remove 30mm rear output flange nut and slide the flange off the output splines..


Step 2: Remove speedometer sender bolt.

Step 3: Remove speedometer sender.
Step 4: Remove the 7 bolts holding housing #4.
Pull off the housing and remove.


Step 5: Using snap ring pliers, remove outer snap ring from the 4wd idler shaft bearing.


Step 6: Remove the 10 bolts holding housing #3 and slide the housing out.

 


Step 7: Remove 2 oil galleys by gently pulling them straight out.


Step 8: Remove the front output idler gear.
 


Step 9: Remove speedometer drive gear.


Step 10:  Remove oil pump gear and lock ball.


Step 11: Remove 63/28N bearing from rear main shaft.


Step 12: Shift into 2wd high. Remove 2wd/4wd shift fork roll pin with 3/16" pin punch.

 


 Step 13: Remove 2wd/4wd shift hub.


Step 14: Remove 2wd/4wd shift collar & fork.


Step 15: Slide off front output gear from output shaft.


Step 16: Remove pair of cage bearings from output shaft.


Step 17: Remove thrust washer & locking ball.


Step 18: Remove front output 30mm nut and flange.

 

 


 Step 19: Remove 4 bolts holding housng #5. Slide housing #5 off.


Step 20: Remove snap ring from front output bearing.


Step 21: Remove front output gear.


Step 22: Unbolt and remove remove shifter base or block off-plate depending on model.


Step 23: Remove 4wd light switch.


Step 24: Using an Allen wrench, remove detent plugs from both sides of case. Rotate case on it's side, and tap case lightly to allow spring and ball to fall out.
 

 


 Step 25: Remove 2 bolts holding housing #1 on the passenger side of case.


Step 25: Remove last 2 remaining  bolts holding housing #1 on the driver side of case.
 


Step 27: Remove snap ring from input shaft bearing.


Step 28: Remove snap ring from idler shaft bearing.


Step 29: Using a pin punch, drive out roll pins from each of the shift rails. Let pins fall in to case.


Step 30: Slide housing #1 forward and remove. Retrieve two shift fork roll pins from bottom of housing.

 

 


 Step 31: Remove input gear.


Step 32: Remove counter shaft gear.


Step 33: Remove pocket bearing from inside of the main shaft.

 


Step 34: Remove the 2wd/4wd shift fork.


Step 35: Remove hi/lo shift fork along with shift collar.


Step 36: Turn transfer case upside down and remove shift fork interlock pin from detent plug hole.
 

 


 Step 37: Remove the 4 bolts holding the main shaft bearing cover. Remove cover.


Step 38: Remove the snap ring on the main shaft bearing.

 


Step 39: Slide housing #2 off of main shaft.


Step 40: Remove snap ring from the main shaft.


Step 41: Remove 6208N main shaft bearing using a gear puller or press.


Step 42: Remove thrush washer and lock ball from main shaft.

 


 Step 43: Remove low speed gear from main shaft. Discard low speed gear.

 


Step 44: Remove cage bearing from main shaft.


Step 45: Remove snap ring from input gear. Discard bearing and input gear.


Step 46: Remove snap ring counter shaft gear. Discard bearing and counter shaft gear.


Step 47: Using end mill or hand grinder clearance case as required to accept new 4.70 counter shaft.


Step 48: Install counter shaft and bearing into housing and spin to verify clearance between gear and housing.

 


 Step 49: Using a hand grinder, remove about 1/8" of aluminum from housing #1 near the oil galleys.


Step 50: Apply bearing grease to the bottom of the main shaft and install low speed needle bearing. Apply another layer of grease on to the outside of the needle bearings.


Step 51: Slide new 4.70 low speed gear on to main shaft and over needle bearings.


Step 52: Apply grease to the lower main shaft ball hole. Insert ball into hole.


Step 53: Apply axle grease to the top face of low speed gear as shown above.


Step 54: Slide thrust washer in to place, lining up the notch in the washer with the lock ball from the previous step.

 

 

 


 Step 55: Slide 6308N down on to thrust washer. Press bearing down until it contacts thrust washer and snap ring grove is visible. Install snap ring above bearing on the main shaft.


Step 56: Slide Housing #2 on to main shaft and seat housing on 6308N bearing.


Step 57: Install snap ring on to the outside of the 6308N bearing.


Step 58: Slide bearing retainer over main shaft and in to place.


Step 59: Install four retainer bolts and torque to 10 ft/lbs.


Step 60: Using a grinder or file, clearance shift fork and block as shown.

 


Step 61: Insert roll pin into low range shift fork. Shaft can go in two ways, install as shown above. Notice position of notches on shift rail during assembly.


Step 62: Place the clutch sleeve into the shift fork and slide fork in to place.


Step 63: Grease the high/low pocket bearing inside and out. Insert bearing into main shaft.


Step 64: Grease both and the counter shaft and idler bearings as shown.
 


Step 65: Install counter shaft gear/bearing assembly as shown.


Step 66: Install input gear/bearing assembly in to main shaft.

 


 Step 67: Place the new gasket on to housing section #2.


Step 68: Slide housing #1 in to place and install bolts as shown. Using a rubber hammer, apply gentle pressure to seat housing.


Step 69: Turn the transfer case around and install two more bolts on the other side.


Step 70: Install the outer snap ring on input gear bearing.


Step 71: Install the inner snap ring onto input gear bearing.


Step 72: Install the outer snap ring on countershaft bearing.

 


 Step 73:  Install the inner snap ring on to countershaft gear bearing.


Step 74: Insert interlock pin in to the driver side detent hole. If installing a twin stick shifter skip this step. Turn the case on it's side to assist in getting pin to drop in to place.


Step 75: Make sure the interlock pin is all the way into position. Here the end of the pin can still be seen through the shift fork hole. Adjust the position of the shift fork until the pin can go all the way out of view.


Step 76: Install shift rail and shift block. On models with a C clip replace clip with the one provided. Install clip as shown.


Step 77: Using a 3/16" pin punch to drive high low shift fork pin in to place.


Step 78: Reinstall front output gear with bearing in to housing #2.

 

 


 Step 79: Install snap ring on front output bearing.


Step 80: Replace seal and felt on housing #5.grease inside of rubber seal surface. 


Step 81: Place front output gasket onto face of housing #2.


Step 82: Slide housing #5 on to front output shaft and install four bolts. Torque to 10 ft/lbs.


Step 83: Apply grease to ball hole on main shaft.
 


Step 84: Place ball in to ball hole on main shaft.

 


 Step 85: Align thrust washer with lock ball and slide in to place over the ball. Grease to face of thrush washer once in place.


Step 86: Grease to inside and outside of output shaft cage bearings. Slide bearings in to position on main shaft.


Step 87: Install front output drive gear on to main shaft.


Step 88: Grease the outer face of front output drive gear.


Step 89: Slide clutch hub in to place on the main shaft. 


Step 90: Place clutch sleeve in to the shift fork. Slide shift fork and clutch sleeve in to case.
 


 Step 91: Using a 3/16" pin punch, drive shift fork roll pin down until it is flush with the fork.


Step 92: Reinstall front drive idler gear.


Step 93: Install output shaft rear support bearing.


 Step 94: Using a screwdriver, remove and replace oil pump seal inside the oil pump drive gear.


Step 95: Slide oil pump drive gear onto main shaft until it seats on bearing.


Step 96: Apply grease to ball hole. Place ball into hole.

 


 Step 97: Align notch in speedometer drive gear with ball on main shaft. Slide speedometer drive gear onto main shaft.
 


Step 98: Place new gasket on to the back of housing #2. Reinstall oil delivery tubes at arrows.



Step 99: Apply grease to cage bearing in back of housing #3.


Step 100: Install housing #3 on to the back of housing #2. Align oil transfer tubes with slots in the back of housing #3. Install 10 bolts into cover #3. Torque to 30 ft/lbs. 


Step 101: Install outer snap ring on idler bearing.


Step 102: Place new paper gasket on to back of housing #3
 


 Step 103: Remove old output seal on housing #4. Install new seal and apply grease to inner lip.


Step 104: Install housing #4 on to the back of housing #3. Install 7 bolts into housing #4. Torque to 30 ft/lbs.


Step 105: Using a screwdriver, remove and replace the speedometer sender seal. Apply grease to plastic speedometer drive gear.


Step 106: Slide speedometer sender into housing #4. Install speedometer lock tab and bolt, torque to 10 ft/lbs.


Step 107: Rotate case so it is on it's side. drop in one detent ball.


Step 108: Next drop in one detent spring.
 


 Step 109: Apply a small amount of silicon to the threads of the detent plug and install. Flip case over on to the other side and install the ball, spring and plug as above.
Step 110: Install 4wd shift light switch into housing #1.


Step 111: Apply ultra gray Silicon to the inside splines of both flanges. Slide flanges in to place on t-case.


Step 112: Install the main shaft nuts and washers. Tighten each nut to 90 ft/lbs. Using punch, stake nuts into the main shaft as shown.
 
 

 

After installing transfer case, use the rear fill plug and fill transfer case with 80/90W GL5 gear oil. Once oil starts leaking out of the fill hole, the transfer case case is full. Transfer case oil should be replaced after 1,000 miles, then at every 30,000 miles thereafter. Conventional or synthetic oil may be used.

These instructions are designed as a general installation guide. Installation of Trail-Gear Products requires specialized skills such as metal fabrication, welding and mechanical trouble shooting. If you have any questions or are unsure about how to proceed, please contact our shop at 559-252-4950 or seek help from a competent fabricator. Using fabrication tools such as welders, torches and grinders can cause serious bodily harm and death. Please operate equipment carefully and observe proper safely procedures.

Rock crawling and off-road driving are inherently dangerous activities. Some modifications will adversely affect the on-road handling characteristics of your vehicle. All products sold by Trail-Gear Inc are sold for off road use only. Any other use or application is the responsibility of the purchaser and/or user. Some modifications and installation of certain aftermarket parts may under certain circumstances void your original dealer warrantee. Modification of your vehicle may create dangerous conditions which could cause roll-overs resulting in serious bodily injury or death. Buyers and users of these products hereby expressly assume all risks associated with any such modifications and use.

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