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Installing 23,000 Volt Offroad Lights

What are HID Lights?

Onboard Air
Converting a York
AC Compressor
to Pump Air

Warn 9500i Winch Installation

HEI Ignition
Installation & Review

Lockers, Limited Slips &
other Differentials Explained

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

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

For all the Jeep
Fans out there!

Offroad Reports

Jeeps at Rausch Creek
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Wheeling in the Valley of the Ferns

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 Model Low Range Type/Output Drive Years Application Avail. Modifications
Dana 18 2.46:1 gear/offset part ‘45-71 CJ,FC,PU,SW,C101 Notes 1,2,3,4,5
Dana 20 2.03 gear/center part ‘63-79 CJ,SJ,C101 Notes 4,5,6,7
Dana 21 1.00 gear/center part ‘63-69 SJ N/A
Dana 200 1.91 gear/center part ‘67-69 M715 N/A
Dana 300 2.60 gear/center part ‘80-86 CJ Notes 8,10
BW-1339 2.57 chain/offset full ‘73-79 SJ Note 9
NP219 2.60 chain/offset full ‘80-82 SJ N/A
NP208 2.61 chain/offset part ‘80-91 SJ N/A
NP229 2.61 chain/offset part/full ‘83-86 SJ N/A
NP228 2.61 chain/offset full ‘85-91 SJ N/A
NP207 2.72 chain/offset part ‘84-87 YJ,XJ N/A
NP231 2.72 chain/offset part ‘88-97 TJ,YJ,XJ Notes 12,13,14
NV242 2.72 chain/offset part/full ‘87-97 XJ,ZJ Note 12
NV249 2.72 chain/offset full ‘96-97 ZJ N/A
NV247 2.72 chain/offset full ‘99 WJ N/A
Atlas II 3.77 or 4.33 gear/center part Aftermarket from Advance Adapters Note 11

CJ=‘45-86 CJ-2A-CJ-8, YJ=‘87-96 Wrangler, TJ=‘97-up Wrangler, PU=‘47-65 Willys pickup, SW=‘49-65 Willys Station Wagon, SJ=Wagoneer, Grand Wagoneer, J-Series pickup, C-101=‘67-73 Jeepster Commando & C-104 Commando, XJ=‘84-up Cherokee, ZJ=‘93-98 Grand Cherokee, WJ=‘99-up Grand Cherokee




Note 1: Advance Adapters Saturn overdrive. This unit fits on the Model 18 ‘45-71 transfer case, though Advance Adapters is working on a version to fit the WWII military transfer cases. It‘s a 25 percent overdrive (0.75 ratio), meaning it drops rpm by 25 percent. It‘s capable of handling up to 300 lb-ft of torque, according to the manufacturer. Note 1
Note 2: TeraLow builds a replacement gear set for the Model 18 with a 3.15:1 low range. The conversion works only on a ‘66-and-later Model 18 cases, ‘63-79 Wagoneer cases, or ‘72-9 Model 20 cases. The Model 20 case can be used with the offset output of the Model 18. Note 2
Note 3: O‘Brien‘s 4-Wheel West makes four replacement gear sets called the JP Rock Eaters for the Model 18 in 3.0:1, 3.6:1 4.10:1 and 4.86:1. The 4.10 and 4.86 kits require significant case modifications. The detailed instructions outline the necessary mods to be performed by competent machinists and certified welders, but O‘Brien‘s can supply modified cases or complete kits. Note 3
Note 4: Hicks 4x4 Specialists offers a kit to drop the Model 20 low ranger from 2.03:1 to 2.46:1. Installation involves only very minor clearance grinding of the case and parts that are stronger than stock. Note 4
Note 5: O‘Brien‘s 4-Wheel West makes a tapered roller bearing kit to replace the roller bearings and thrust washers of the original setup. this is an option to the company‘s Model 18 and Model 20 Rock Eater kit, and it significantly quiets the Model 18 unit. O‘Brien claims a 300-325 percent over design compared to the stock setup. Note 5
Note 6: O‘Brien‘s 4-Wheel West offers two replacement gear sets for the Jeep Model 20 in 3.0 and 3.6:1 ratios. No welding is required, and only minor mods are necessary to the case and shift rail. Note 6
Note 7: TeraLow offers a 3.15:1 low-range gear set for the Jeep model 20 in a kit that contains everything needed to do the swap. It requires only minor clearance grinding of the case for the larger gears. Note 7
Note 8: TeraLow‘s Dana 300 kit offers a whopping 4.0:1 low-range option. These quality gears are said to be very quite. Normally, clearance grinding isn‘t necessary for installation, but a tiny bit of grinding in one strategic spot will make assembly easier. Note 8
Note 9: MileMarker‘s part-time conversion for the BW-1339 Quadra-Trac eliminates the fuel-sapping full-time system, annoying clutch chatter, and need for special oil. It includes a new chain and locking front hubs. Note 9
Note 10: Currie Enterprises Twin-Stick shifter for the Dana 300 evolved as an answer to automatic lockers up front. It allows the front axle to be uncoupled from the transfer case while in low-range. This is easier than climbing out and unlocking a hub to make a tight turn or shifting out of 4WD and low range at the same time. Note 10
Note 11: The Atlas II transfer case is manufactured by Advance Adapters and can replace nearly any transfer case in nearly any Jeep. It‘s an aluminum cased, gear driven design that‘s based on the best features of the bulletproof NP205 and Dana 300 transfer cases. It‘s available with 3.77 or 4.33:1 low-range gearing. Note 11
Note 12: Short-tailshaft kits for NP231s, and NP242s have appeared from a variety of manufacturers to answer the needs of lifted rigs with drive shaft angle problems. They‘re all variations on the same theme: conversion of the sliding rear output shaft to a fixed yoke and the loss of about 4 inches of drive line length. In the case of the JB Conversions kit, the replacement rear-output shaft is at least 50 percent stronger than the stock one. Note 12
Note 13: TeraLow‘s 4:1 low range kit for the NP231 includes a new heavy-duty rear case as well as a six gear planetary gear set that offers a 4.0:1 low range gearing. Note 13
Note 14: If you combing an NP-231 and an automatic front locker, you may experience the need for a 2WD low position on the transfer case to make trail maneuvering easier. Both TeraLow and JB Conversions supply suck a kit to add and extra position to this popular New Process case. Shown are the TeraLow pieces. Note 14




The preceding data was from "Jeep Transfer Case Encyclopedia" an article found in the November 1999 issue of Jp Magazine.

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An ongoing Budgeted Rebuild/Build up of a Rock Crawling Machine.

Jeep Wrangler JK
Jeep JK Specs

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


Offroad Tire Info
P-Metric Tire Sizes Conversion to Inches
Tire Terminology
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Tires for your Truck
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All Terrain  Mud Terrain
Tire Reviews & Info
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Super Swamper Bogger
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Federal Couragia MT
Firestone Destination AT
Firestone Destination MT
General Grabber MT
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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 Terra Grappler
Nitto Dura 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 AT
Toyo Open Country MT
TrXus Mud Terrain
TrXus STS All Terrain
Michelin LTX A/T˛
Michelin LTX AT2 Press
Michelin LTX AT2
Mickey Thompson MTZ
Mickey Thompson MTX
Mickey Thompson Baja Claw Radial
Mickey Thompson Baja Claw Bias
Mickey Thompson Baja Crusher
Mickey Thompson Baja ATZ Radial SLT
Competition Claw
Dunlop Mud Rover
Federal Couragia M/T
Nitto Dura Grappler
Yokohama Geolandar
Dick Cepek's 2008 F-250 Super Duty Project Vehicle – Project CRUSHER
Mud Tire Reviews

Strange and Unusual Vehicles & 4x4s

Jeep V8 Swap Tips

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.

The Jeep Timeline

Jeep road car timeline, 1945 to Present  -  Jeep, A subsidiary of DaimlerChrysler

1940s 1950s 1960s 1970s 1980s 1990s 2000s
5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Traditional CJ-2A
Wrangler YJ
  Wrangler TJ
                                                                        CJ-8                                   LJ      
                    CJ-5 - 1955-1983                                             Wrangler JK
                    CJ-6 - (stretched CJ-5) - 1955-1981                                                   JK Unlimited
                    Jeep DJ Postal / Dispatch Jeep / Surrey Gala Package                                                  
Mid SUV       VJ
                              C101 C104                                                       Liberty KJ
Large SUV                                     Wagoneer / Cherokee SJ Grand Wagoneer   Gr. Cherokee ZJ Gr. Cherokee WJ Gr. Cherokee WK
                                                                              Cherokee XJ         Commander
Pickup                                     Gladiator Honcho
                                    J-Series Pickups                                            
Truck                       Forward Control
FC-150, FC-170
                                  FJ-3, FJ-3A Fleetvan                                                                    
Crossover                                                                                                                             Compass
Other                           JEEP Concept Vehicles - Experimental, Prototype Concepts