D20 Popping out of 4 wheel drive

[Johnnyb]

Took the old EB out Wheeling today on a fresh rebuilt Dana 20 with JB Fab twin stick, rails and adjustable detents. Had a mixed experience as it would not stay in 4-wheel drive. The symptoms we're a bit puzzling because when it popped out both axles went to neutral. It was worse in low range, in fact I could barely keep it in low range for a few seconds under load, and high four wheel it would stay in under most circumstances, thankfully I have granny in the new process so I was able to get by.

I've looked at the similar threads and of course I'll look at the linkage and the JB Fab adjustable detents. Jon at @JB Fab suggested I might reverse my springs.

Just wondering if anybody had some fresh thoughts on where I might start diagnosing.

THX,
JB

 

[mrdrnac]

Check to make sure that the shifters are not contacting (or very close) to the body metal of the tunnel. Trim more if needed. And did you set the output shaft up with clearance or with a preload?

 

[Madgyver]

I have the same issue, I use a short bungie cord and go shifter to dash.
hook to underside of dash and loop around low shifter and then back to other hook under dash.
It works so I never got around to doing anything about it.

 

[JB Fab]

Reverse springs? No the adjustable detent kit springs are the same.
If it is popping into neutral from 4L or 4H that means BOTH front and rear shift-rails are moving. Assuming that all of the shim packs (VERY important) were properly set-up, I would tighten the adjustable detents until it gets almost too hard to shift, then back off a little.

Try that and give me a call....

Jon

 

[Johnnyb]

Reverse springs? No the adjustable detent kit springs are the same.
If it is popping into neutral from 4L or 4H that means BOTH front and rear shift-rails are moving. Assuming that all of the shim packs (VERY important) were properly set-up, I would tighten the adjustable detents until it gets almost too hard to shift, then back off a little.

Try that and give me a call....

Jon

Thanks Jon!
I thought you suggested turning the springs upside down in case one end had become larger and was not supporting the ball properly?

 

[bmc69]

I have the same issue, I use a short bungie cord and go shifter to dash.
hook to underside of dash and loop around low shifter and then back to other hook under dash.
It works so I never got around to doing anything about it.

My fix too ^. On the EB race truck, nothing we could do to the t-case would prevent it from popping out of 4-low during a race. Bungee did the trick though.

 

[JB Fab]

Thanks Jon!
I thought you suggested turning the springs upside down in case one end had become larger and was not supporting the ball properly?

Yes! I misunderstood your post, I thought you were swapping locations. If the adjustable detents might have gotten overtightened, the spring can expand around the detent ball and jam the shift-rail. flip them over to use them until they can replaced.
Jon

 

[JB Fab]

Bungee cords are ok in a pinch, but a healthy case will stay in gear by itself.
Constant pressure on the the shifter means your shift-fork is riding on the sliding gear under pressure.

 

[Viperwolf1]

Bungee cords are ok in a pinch, but a healthy case will stay in gear by itself.
Constant pressure on the the shifter means your shift-fork is riding on the sliding gear under pressure.

And this will wear out the fork and sliding gear over long term use, creating a bigger problem. The bungee would be a trail fix, not a solution.

 

[Johnnyb]

It is a fresh rebuild. I removed T-Case and installed it, so if it is a linkage or clearance issue, it is on me. If it is not fully-engaging detents, it should be warranty.

In any case, I would rather have optimal functionality at this point and avoid the bungees if possible!

-JB

 

[Madgyver]

And this will wear out the fork and sliding gear over long term use, creating a bigger problem. The bungee would be a trail fix, not a solution.

I'm hardly ever in 4 low for long durations on our trails..

 

[Johnnyb]

I'm hardly ever in 4 low for long durations on our trails..

I use it all the time! With the NP435, 3rd (of 4) is the power gear, and I can control the speed perfectly just by selecting a gear, hardly ever need to touch the throttle. Plus for obstacles 1st. (granny) or 2nd. are perfect. And If I feel like taking a leak, I can put it in first, get out, P, and the truck hasn't even passed me.

-JB

 

[Johnnyb]

I am going to pull the boot and tunnel-cover off and go out wheelin' again next weekend. Maybe I am contacting body metal at some point, but wheelin' with the tunnel open (if windy and hot) will eliminate that! I'll let everyone know the outcome!

THX,
-JB

 

[Johnnyb]

Well I went out again with no possibility of interference from body metal or the shift Boot and it is still popping out, especially the rear axle in low range.
There's a clear detent in the shifting, in fact I have the detents set tight enough that I have to really pull on the shifter to get it out, yet it's popping out of low range on the rear axle almost every time I get on it.
I guess it's time to pull the case and see what I can see.

-JB