The difference between Dana20 T& the J

[RedLeg0811]

I was trying to figure out how to tell if I have a Dana20 T or a J. How do you tell?

Thanks
Martin

 

[76Broncofromhell]

There's a bar connecting the T-shift rails together and a different style yoke. I recommend searching as this has been covered many many times before. Check the tech section as well.

 

[DonsBolt]

What year is the truck
J started in 73

When you shift yout transfer case, is it a straight push/pull. or do you have to swing the shifter back and to the left(in a backwards J pattern)??

 

[rjlougee]

Sometimes shifters get replaced, either a twin stick or somethingelse, so that may not be easily recognizeable as a T or J shift pattern.

In that case, take a look at the shift rails on the T-case. If they have (or had) what appear to be welded on tabs, then it's a J-shift. If the shift rods have a hole drilled in them for the pins to pass through (roughly 1/4" diameter), then it's a T-shift.
Joe

 

[jbbies]

Im assuming the J is better because its in the newer broncos like the (dana 30 and 44) Is there advantages to either?

 

[trailpsycho]

NO advantages...the T- actually has slightly lower gearing, but its not much.

Like most things, its taking advantage of what you have/want. The J-shift advantage is...cut the flags on the shift rails and the TC can shift either axle independantly of the other (be careful not to have one in high and one in low) allowing for front wheel drive hi/lo or rear wheel drive hi/lo.

With the T-shift, you have slightly lower gearing, which is a good thing. The detents are reportedly different however and will not allow independant operation of the front axle, if I remember correctly, without the rear axle also being in that gear...so you would have rear hi/lo but not be able to shift the front in hi/lo unless the rear was there. And I could be slightly wrong on this....but to get the same truly independant shiftability, my understanding is you need to modify the shift rails--this is documented several times here in the archives. Some have removed the pils from the T to get the desired action, but this also promotes the popping out of gear.

Any of these cases are good...oh yeah, one more thing, IF you wanted to convert over to the Jack Obrien JeepEater gears (4.86) in the TC, then you need the internals of a T-shift...a J-shift internals will not work. With the Terra Lows gears (3.18) either case can be used.

Someone please correct me on any of the above if I mis-spoke. Good luck.

 

[RedLeg0811]

Thanks all.