CJ-7 Projects


Lightforce Lights - H.I.D. High-intensity discharge Upgrade

HEI Ignition System (GM Style) Installed in the AMC 360 V8
Getting rid of gremlins and improving performance

Installing 23,000 Volt Offroad Lights

Autogage Tachometer Installation

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 Centralia PA
Project CJ-7
Offroaders Guide
to Gearing up
for Offroad

From Basic Equipment to Well Equipped.  An extensive list guide to help you prepare your vehicle for the offroad.


Onboard Air
Converting a York
AC Compressor
to Pump Air

Trailering Safety and Trailer Hitch Information


Off-Road Truck Driving Techniques and Safety

Off-Road Lights
by LightForce Product Review / Installation.
from Off-Road Lights


Jeep Dana 300 TeraLow - 4:1 Gearset for the Dana 300 Transfer Case

AMC V8 Engines
GEN-1 Nash/Hudson/Rambler V-8s (1956-1966) through to the GEN-3 AMC Tall-deck (1970-1991)

Chevy Small-Block V8 Engines
Chevy Small-Block V8 Engines Manufactured by General Motors - Production: 1955?2002

Hemi Engine - All about the Hemi Engine

Ford Engines
4 Cylinder, 6 Cylinder, 8 Cylinder, 10 Cylinder, 12 Cylinder Ford Engines

Ford V8 Engines
8 Cylinder Engines manufactured by Ford

Ford 351 Cleveland V8 Engines
351 cubic inch V8 Engines manufactured by Ford

Chrysler Hemi Engine

AMC V8 hp/Torque, Compression & Bore/Stroke by year

Engine Size Conversion Table
Converting engine displacement from CID, Liters, C.C.

Engine Overheating Basics - 16 Common Causes of an Overheated Engine

Fan Clutch Diagnosis
How to tell if the Fan Clutch in your Cooling System is failing or has failed.

Automotive Gauges & Instrument Functions
Information they display & their importance.


From the
Department of Cheap   Tricks and Useful Tips

Ultra-Cool Hand Throttle for Free!

Jeep V8 Swap Tips

The Exploding Clutch

Radiator Protection using 6 bucks worth of material

Cracked Under Pressure - Fixing a smashed fingernail

A Cheap, effective alternative to undercoating

Home-built Saginaw Gearbox Brace for the cost of lunch!

Ammo Box Storage - Mounting Them for Quick Disconnect

Home-built Serious Skid-Plate protection for the Oil Pan for under 20 bucks!

Ramp Travel Index
RTI / Ramp Travel Index  What it is and how to calculate it, with and without the ramp.





Project Jeep CJ-7
TeraLow Gears
Grinding the Case

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Disassembly of the Dana 20
Breakdown of the Dana 20 case

Grinding the Case of the Dana 20 Transfercase
Grinding the metal to clear the Teralow gears

Reassembling the Teralow Dana 20
How it all goes back together.

Teralow Dana 20 Reviews
What people think of the Teralow Dana 20 Kit

Crawl Ratio Calculator


Grinding The Case

Most Dana 20 cases will need grinding to clear the Rear Sliding Gear (TL20-E) of the Teralow gearset.  Teralow suggests some will not need grinding.  If it does need grinding, the question is how much.  To check clearance I attached the rear output shaft assembly to back of case and attempted to put the Rear Sliding Gear on.  For my case, it wouldn't go on so grinding was necessary.  Below are the examples of where Teralow suggests you will have to grind.

Dana 20 case
before grinding.
Dana 20 case
after grinding.
Note: Most Dana 20s require grinding. Even if your case doesn't seem to need grinding, be sure to check the Slide gear through positions with shaft and sliding output gear in place to make sure case clearance is complete.
The area that needs grinding can be tricky to get to.  I tried this idea below attached to a drill which worked somewhat however the wheel seemed to get chewed up quickly, probably because I wasn't spinning it fast enough.



After some initial grinding I was able to get the gear into the case for a test fit.  I rolled the gear and marked contact areas with a black sharpie.

I had contact in several places.  It took several rounds of marking and grinding to get it right.

For better grinding, I resorted to my favorite tool, the angle grinder.  I took the shield off and was able to get it into the case to where the grinding was necessary.

CAUTION: When grinding and removing material from the case REMEMBER!  You can take material off the case but you can't put it back on!  Only grind a little at a time and test it.  Don't go crazy and grind a hole right through the case!  You only have to clear by a very small amount so trim lightly!

This is where most of the grinding was necessary.

I also found that it might be possible that the gear could make contact when fully engage the other way so I trimmed a very small amount of material off the other side.  CAREFUL!  There isn't much material there.  I didn't want to risk a hole in the case.


I was making final checks on clearances.  When I was happy that the gear cleared, I was ready to clean it up and start the assembly process.


Cleaning and inspection


I washed all transfer case components except the
Rear Output Housing assembly.  With the Rear Output Housing, I was careful not to get it dirty because I wasn't taking it apart.  Only the removal of the gasket on the Rear Output Housing was necessary. 

The rest of the transfer case including the housing and re-used parts were washed in hot water and Simple Green.   I also cleaned the gasket material from all gasket surfaces and dried all components with compressed air.

At this time I inspect all parts that were to be re-used including bearings, thrust washers and gears for excessive wear, pitting, and scoring. If any part is damaged or worn, it must be replaced.


Painting Parts


If you're like me and you live in an area where rain, snow, ice and road salt are constantly assaulting your vehicles, then you'll know why I like to paint everything.  I hate rust.  So after the parts were cleaned of the grease and dirt, I gave everything a coat of gloss black.  I like to use Rustoleum.  I've been using it for years and it seems to hold up pretty well to the elements.

Everything else was cleaned well and painted.  Don't paint the machined gasket surfaces.  Either tape them up or spray carefully and wipe off over spray.  Since I wasn't disassembling the rear output housing, I cleaned the surface and kept the gears and bearings dry and clean.



Disassembly of the Dana 20
Breakdown of the Dana 20 case

Grinding the Case of the Dana 20 Transfercase
Grinding the metal to clear the Teralow gears

Reassembling the Teralow Dana 20
How it all goes back together.

Teralow Dana 20 Reviews
What people think of the Teralow Dana 20 Kit

Crawl Ratio Calculator


Tera Manufacturing, Inc.
5251 South Commerce Dr.
Murray, Utah 84107


Torque Specifications:

Torque Specifications     Foot-Pounds
Front and Rear Output Shaft Yoke Nuts   225-250
Right and Left Shift Fork Setscrews   12-15
Shift Rod Housing to Case Bolts   28-30
Front Output Shaft Rear Bearing
Cover to Case Bolts
Intermediate Shaft Lock Plate
to Case Bolts
Rear Bearing Cap Assembly
to Case Bolts
Lower Cover to Case Bolts   12-15
Transfer Case to Transmission Bolts   28-32


Click to zoom in

Items underlined and bold below are included in the Tera Low20 low range gear kit

1. Shift Rod    33.  Intermediate Gear Shaft
2. Shift Rod   34. Thrust Washer (2)
3. Shift Rail Seal   35. Bearing Spacer (3)
4. Shift Rail Interlock   36. Needle Bearings
5. Shift Rail Interlock   37. Intermediate Gear (TL20-B)
6. Detent Springs         38. Cover Gasket
7. Detent Balls   39. Cover
8. Front Output & Shift Rail Housing Seal   40. Drain Plug
9. Washer   41. Main Drive Gear (TL20-A)
10. Front Output Bearing Race   42. Rear Sliding Gear (TL20-E)
11. Front Output Bearing   43. Set Screw
12. Shift Rail Caps   44. Rear Wheel Drive Shift Fork
13. Case Housing   45. Rear Output Shaft
14. Tranny to Transfer Case Gasket   46. Rear Output Bearing
15. Front Output & Shift Rail Housing   47. Rear Output Bearing Race
16. Front Yoke Seal   48. Speedometer Drive Gear
17. Front Output Yoke   49. Rear Output Shaft Shims
18. Yoke O-ring   50. Rear Output Housing Gasket
19. Flat Washer   51. Rear Output Housing
20. Companion Flange Nut   52. Breather
21. Washer   53. Rear Output Bearing Race
22. Front Output Gear (TL20-C)   54. Rear Output Bearing
23. Front Sliding Gear (TL20-D)   55. Rear Output Yoke Seal
24. Shift Fork Set Screw   56. Rear Output Yoke
25. Front Wheel Drive Shift Fork   57. Flat Washer
26. Front Output Shaft   58. Companion Flange Nut
27. Front Output Bearing   59. Speedo Driven Gear Busing
28. Front Output Bearing Race   60. Speedometer Driven Gear
29. Front Output Bearing Cap Set   61. Speedometer Driven Gear Sleeve
30. Front Bearing Cap      
31. Intermediate Gear Shaft Retainer      
32. Intermediate Gear Shaft O-ring      


Other Teralow Resources:
Great deal on the Tera Low20 from OK4WD
Dana 20 Tera Low20 for Manual Transmissions

Related: Dana 300 Tera Low Install
There are several models of the TeraLow, there are TeraLow's for Dana 300 (4:1), Dana 20 (3.15:1), Dana 18 (3.15:1), and NP 231 (4:1).

Transfer Case Upgrades, Modifications, and Options
Jeepfan.com - There are several modifications that can be performed on a Jeep transfer case.  Most involve replacing the gears in the case to lower the gear ratio to improve slow trail performance.


Teraflex Dana 20 Low Range Kit install / Review
Pirate4x4.Com reviews the Teraflex Low20 Kit including Case Grinding, Installing and testing

Installing TeraLow Gearset - Dana 20 Transfer Case
For hard-core 'wheeling, slower speeds mean greater control and less strain on your drivetrain...Swapping in lower (numerically higher) gears into the axles will certainly help..

Tera Low Dana 20 Gears Review / Install
JeepWire.Com product Review of Tera Low Dana 20 gears.

Project Jeep CJ-7 ~ The Dana 20

Back to Project Index




Offroad Tire Info
Tire Terminology
Wheel Terminology
How to Pick the Right
Tires for your Truck
Truck Tire Info
Tires - What Hits What Fits
All Terrain  Mud Terrain
Tire Reviews & Info
Mud Terrain MT Tire Reviews
All Terrain AT Tire Reviews
Super Swamper Bogger
Super Swamper SSR
Super Swamper SX
Super Swamper Vortrac
Interco IROK TSL
Super Swamper LTB
Super Swamper TSL
Super Swamper TSL Radial
Super Swamper Narrow
Interco SS-M16 Swamper
Thornbird TSl Radial
Thornbird TSl Bias
Thornbird TSL
Parnelli Jone Dirt Grip
BFGoodrich Krawler
BFGoodrich MT T/A KM
BFGoodrich MT T/A KM2
BFGoodrich AT TA KO
BFGoodrich Mud King XT
Bridgestone Dueler MT
Cooper Discoverer ST
Cooper Discoverer STT
Cooper Discoverer ST/C
Firestone Destination MT
General Grabber MT
General Grabber AT2
Green Diamond Icelander
Ground Hawg Mud Tire
Hankook Dynapro MT
Hankook Dynamic MT RT01
Hercules Terra Trac MT
Hercules Trail Digger MT
Kelly-Springfield Safari DTR
Kelly-Springfield Safari MSR
Kumho Road Venture MT
Kumho Road Venture KL71
Kumho Road Venture AT
Dick Cepek Mud Country
Dick Cepek F-C II
Dick Cepek Fun Country II
Dick Cepek Fun Country Nylon
Dick Cepek Fun Country Kevlar
Mastercraft Courser MT
Mastercraft Courser HTR
Mastercraft Courser HTR Plus
Maxxis BigHorn Radial
Maxxis Creepy Crawler
Maxxis Trepador
Maxxis Buckshot Mudder
Maxxis MA-SW
Maxxis M-8080 Mudzilla
Maxxis MT-754 Buckshot
Maxxis MT-753 Bravo
Maxxis MA-751 Bravo
Maxxis MA-S2 Marauder II
Maxxis MA-S1 Marauder
Maxxis MT-762 BigHorn
Nitto Mud Grappler
Nitto Dune Grappler
Nokian Vatiiva MT
Pit Bull Rocker Extreme
Pit Bull Maddog
Pit Bull Growler
Goodyear Wrangler MT/R
Pro Comp Xterrain
Pro Comp All Terrain
Pro Comp Mud Terrain
Pro Comp Xtreme AT
Pro Comp Xtreme MT
Toyo Open Country MT
TrXus Mud Terrain
TrXus STS All Terrain
Mickey Thompson MTZ
Mickey Thompson MTX
Mickey Thompson Baja Claw
Mickey Thompson Baja Crusher
Competition Claw
Dunlop Mud Rover
Yokohama Geolandar

Latest trips Offroad
... trail reports with the Project CJ-7
click here.

Sounds System, Raised the Rear Seat
Storage below and a great place to mount 6x9 Speakers for Great Bass ... In a Jeep!

York AC Compressor Conversion.  What used to pump Freon, now pumps compressed air to the front and rear bumpers.  125 psi,  2 gallons of storage, air fittings at the bumpers, enough CFM to power air tools!.  Click Here for more  Details


Dick Cepek's 2008 F-250 Super Duty Project Vehicle ? Project CRUSHER

Warn X8000i
Winch Installation

ARB Air Locker Install
Jeep Wide Track Axles Swap

Mud Tire Reviews

Building a Garage?
Need a Garage Plan?

Reader's Rigs and Seriously Stucks!


Jeep Trans Swap Info
T-18A Transmission Rebuild & Short Shaft Conversion