Dana 20 Problem

[Harlen Shaw]

I have a Dana 20 that only shifts 4h 2h and 2l (no 4l). I'm not sure exactly how they work and was wondering if any of you might know whats wrong before I take it out and start taking it apart to try and figure it out. Its not stock and was put on the Jeep before I bought it. Other than not shifting into 4low it seems to work great.

 

[Saddle Tramp]

If the 20 is not original to your jeep then it could be the FSJ version which pushes to the side and then forward; the CJ version is straight front to back. See Pictures.

 

[BajaEdition]

the Dana 20 is closely related to the D18
and it has a simular shifting pin setup, If you have a twin stick that will not go into 4 low a good place to start is in the shifter pin area.
what I mean is there are 2 pin things (shifting rails)that the shift forks are connected to, if they are blocked from moving properly they will inhibit the shifting process.
Now if this is not the case I strongly suggest pulling the tranny and case at the same time and opening the case up, it seems that you can drop parts if not careful when handling them separate. Or maybe I am just a fumble thumb.
Anyway once out and connect to the tranny, operating the case is easy and if the case needs internal help you have everything together to see how it fits back together.

 

[Harlen Shaw]

If the 20 is not original to your jeep then it could be the FSJ version which pushes to the side and then forward; the CJ version is straight front to back. See Pictures.

Its definitely not the FSJ version only move straight forward and back. I looked underneath its not possible for the side movement.

 

[Harlen Shaw]

the Dana 20 is closely related to the D18
and it has a simular shifting pin setup, If you have a twin stick that will not go into 4 low a good place to start is in the shifter pin area.
what I mean is there are 2 pin things (shifting rails)that the shift forks are connected to, if they are blocked from moving properly they will inhibit the shifting process.
Now if this is not the case I strongly suggest pulling the tranny and case at the same time and opening the case up, it seems that you can drop parts if not careful when handling them separate. Or maybe I am just a fumble thumb.
Anyway once out and connect to the tranny, operating the case is easy and if the case needs internal help you have everything together to see how it fits back together.

Its a single shifter that is connected to two input shafts. I'm not sure which one affects which part of the Transfer Case . From what I can tell nothing is blocking it. Gonna play with it a little more hope fully its something simple.

Thanks for the advice on dropping the Transmission at the same time, guess that'll be a good time to replace the cracked bell housing.

 

[BajaEdition]

ok there may be a interlock between the pins sticking

and I am not sure if it is true with the Dana 20 , but a D18 shares fluid with the tranny

 

[IOPort51]

there is not a 2L unless it is twin sticked.

I would want to check the front output shaft shifting fork set screw. I would definatly say it has something to do with the front output shaft gear not moving weather from linkage or the fork being loose on the shaft. If the shaft is moving there has to be something loose or missing inside.

 

[BajaEdition]

that is right

check the shfter mechanism for sure

 

[Harlen Shaw]

View attachment 4879

This it what it looks like in 4H all the way forward. When I shift it one position back to 2H the shaft on the left moves back one position and the one on the right stays where it is. When I put it in N the shaft on the left stays put and the shaft on the right move back again. When I put it all that back into 2H which I believe should be 4H the shaft on the left stays put and the shaft on the right goes back another position.

Hope it makes sense how I described it. A little chart below kinda describes the position on each shaft in each setting. 1 is the most inward position and 3 is the most outward position. I'm pretty sure that just the left shaft should have one more position but I'm not sure exactly which way it should be for 4L

Left Right
4H 2 3
2H 1 3
N 1 2
2H 1 1

 

[IOPort51]

the point is that the shafts move when the shifter is moved, is this right ?? If this is the case the front output shaft shifter fork is not moving the sliding gear into the 4 low position. the 4 H position is a completely different set of gears.

please fill out your profile .

 

[Harlen Shaw]

the point is that the shafts move when the shifter is moved, is this right ?? If this is the case the front output shaft shifter fork is not moving the sliding gear into the 4 low position. the 4 H position is a completely different set of gears.

please fill out your profile .

Profile filled out.

So, basically I need to drop it and open it up and see whats going on in the inside, right?