Marlin Crawler Dual Case Adapter (21 and 23 Spline)

Marlin Crawler. Definitely the most respected name in the Toyota off road industry for the amount of time and effort put into an affordable and effective way to lower your gearing..

If you have heard of the term "Rock Crawling"? Chances are you have. But what you may not know is that this now household term was created by Marlin Czajkowski of Marlin Crawler. Invented in April of 1994 (the "MC01"), Marlin has invested more time and energy than any one else in the world on Toyota dual case setups.

The backbone of Marlin's revolutionary design is the Double Roller 32-ball mainshaft bearing which prevents coupler failure and keeps you moving on the trail. This is one single 32 Ball bearing, its like 2 bearings in one (30 mm wide, approx 1 3/16") with a static load rating of over 11,600 lbs! Countless Big block V8s, 350s, V6s, Vortecs, Supercharged 3.4L setups in Tacomas, 4Runners, and T100s, and a 4.7L V8 Tundra - all are using Marlin Crawler Adapters with the Double Roller Bearing and heat treated output shaft.

Shipping Weight 15lbs.

Frequently Asked Questions:

Question: Do I need 21 or 23 Spline?

Answer: If you have a Turbo 4CYL transfercase with a 23 Spline input then you would use a 23 Spline coupler.

OR

If you are purchasing either a 23 Spline (stock) input gear (available through Low Range Off Road) or 23 Spline 4.7:1 Transfercase gearset, you could use the 23 Spline setup in the back transfercase.

If you do not plan on running a turbo transmission (R151F) then your best option for gearing would be to: Buy a 23 Spline Dual Case Adapter and a 23 Spline 4.7:1 gearset to run in the back case.

If you are on a budget and are trying to run dual cases then your best option would buy the 21 Spline dual case adapter.

In order to run a dual cases, your second case must be top shifting. What does this mean? If your transfercase has a steel plate on top covering the shifter hole, and the shifter forks are protruding out of the front of the case, then you have what is called a forward shifting transfercase.

To find out what your factory installed transmission is, and whether or not yours has a forward or top shifting transfercase, please click here:

VIEW TRANS RATIO/TCASE CHART

What you are looking for is a top shifting, gear driven transfercase. The most desireable would be the transfercase found behind a W56-A and B, found in 1985-1988 Toyota Pickups and 4Runners, but as you can see in the chart there are others. that are gear driven- they would just have to be converted to be top shifting.

Obviously we didn't cover all the combinations here, so if you need help in what you can and can't convert please call us and we will be more than willing to help you out.