Dana 20 shifting issues with C4

[genthree]

Update:  rebuilt Dana 20, rebuilt C4, rebuilt 302....  All by me, so confidence is a little in question.

Question is this....  How hard should it be to shift into 4WD?  It is a 73 with a T shift handle.  I have to force the lever REALLY hard to get it to shift.  Anyone else have this issue?  What do you do to get rid of this?  I bought a twin stick today from Tom's to see if that helps, but there must be something I am missing.  Put the twin stick on tonight on the bench and I can shift pretty freely between everything except 4HI front.  I have to give it a pretty good "pop" with my hand to get it to move.  4LO seems to be pretty good, but it is not hooked up to the C4 right now. 

Will update within the next couple of days, but just wondering if there are some secrets...

 

[Bully Bob]

Seems we used to have many guys with driveline experience/knowledge here but, they seem

to remain silent these days..??  Sooo.., you're-da-man.. >< <'>  

We're depending on you ...  /

What I can tell ya is with the unit being cold., shifting may be tighter.

BTW.., is the gear oil in the case..?

Roll it upside down & back up to wet the shift-shafts..? (they're up high & out of the oil.)

Also, try having your son wiggle/turn the yoke(s) a bit while shifting to see if that helps.

New parts may need breaking-in..?

Actually, effort between indents in shifting is good in the sense that it will stay in that gear.

With eng. running & warmed up.., moving trannie in-n-out of gear helps T-case shifting.

(I've had to do this on occasion)

Same goes for unlocking hubs.  Forward/reverse bumping frees them up.

 

[genthree]

Thx Bully... still on the bench and i installed the TBP twin shift on it. Not

Connected to the C4 but i can do all the shifting i want right now. 4hi on the front shaft takes anpretty firm tap with the wrist, but 4lo is pretty easy. Matt at Toms said his dad had a bronco with a C4 and it was always tough to shift at the dana. He gave me some tips to try that may help. Hopefully just separating the two shafts will help. I will update when i get the TC hooked back up to the C4.

 

[Bully Bob]

That was my understanding.., that the shafts moved seperately, with the connecting tab removed.

RU saying yours are still  connected with that flat tab thinge..?

 

[genthree]

no, it one stick controlling both selector shafts.  it was a real bear to get to shift.  hoping that by going to the twin shift it will be easier because one shifter, one shift rail...  we will see...

 

[Bully Bob]

Yes in deed.., (stock T-shift, same as mine)

However, your posts #1 & #3 above states you already had/have the twin stick set-up on..?

Post #1  (Nov. 1) "Put the twin stick on tonight on the bench and I can shift pretty freely between everything except 4HI front.  I have to give it a pretty good "pop" with my hand to get it to move."

Post #3  (Nov. 5)  "... still on the bench and i installed the TBP twin shift on it."

Sooo., I'm guessing you are having equal issues with the "T-shift" AND the "Twin" ...???

 

[genthree]

I added the twin shift as I was finishing the rebuild on the engine and the C4.  I had everything out so I put a twin stick in and haven't got everything put back together to give it a try yet.  I remember that my '69 (3 spd) wasn't that hard to shift, but my '73 (C4) has always been hard to shift.  Just wondering if there is a genetic flaw with these two (C4 and Dana 20) and what other tips people may have to make it easier to shift.

BTW, the twin stick install required a little cutting at the opening and a little modification of the metal tabs that attach to the shift rails.  Pretty easy project if you have everything apart.

I will keep you posted, because I KNOW you want a set /emoticons/[email protected] 2x" width="20" height="20" />

 

[Bully Bob]

Hmmmm..., I can't imagine the D-20 knowing what trannie it's hooked to.

Over the yrs., I've not heard anyone say "the D-20 is EASY to shift"

I think it's just the nature of the beast.

Seems switching to the "J" shifter in later yrs. made it easier BUT., they get sloppy after time.

My "T" works fine. A bit fussy on occasion but, I won't change to the "twin"  unless I

have a serious issue requiring  T-case removal.

          (Really do like the idea of the twin shifter though..!!)

I think you're the 1st. on this board to provide info. on this mod & the proceedure....

 

[genthree]

I did not separate the shift rails inside the TC.  This would give me full independent selection of all options, (ie: Front wheel drive only in HI or LO range).  This would also allow my kids to select HI in the rear and LO in the front and destroy the drivetrain.  (I chose NOT to do this modification.)  "If it is foreseeable, it is preventable."

With the shift rails still "connected" I can select rear-only 2L, which I can see wanting.  I have read some comments that the torque may be too high for this configuration, so I don't know if I will spend much time in 2LO.

I will post some comments as soon as I get it back on the road and I can play with it a bit.

 

[Bully Bob]

WOW..., I did not know the shift rail/shafts were connected internally....

I'm going to have to re-disasemble my spare D-20 & check that out.

The twin shifter nobs are marked;

          (top to bottom)

     FRONT  low-neutral-high

      REAR   low-neutral-high

If one were in low & the other in high.., one *** would be way forward.., and the other way rearward.

Wouldn't it be difficult to make that mistake...?

The way I view it.., the nobs are side-by-side when in proper gearing.

-OR- one *** in neutral (center) & the other in either low or high.  (for one axle drive only)

Maybe talk to TBP & let us know if the "twins" are that much of a problem (req. T-case disassembly, etc.)

TKS.,

Bob

 

[genthree]

They were VERY up front with the issues of making the modification and disconnecting the connecting pins.  You only need to open the case if you are going to remove the interlock pins for full independent shifting.

You are correct that it would be very obvious to anyone with knowledge of the bronco, but I was talking about my kids...

The shift rails have two interlock pins that travel in recessed notches that don't allow travel out of a certain sequence.  That sequence is rear drive to either HI/LO then the front drive to the corresponding HI/LO.  Then when shifting out of 4WD the front drive need to come back to neutral before the rear drive can move.

Very simple design when you look at it....  It would be nice to have the ability to have just front wheel drive (out on the trail and blow up a rear driveshaft), but I felt that the risk was too high...