The Stovebolt Site Forums The Shop Area Driveline Shifter Box

1953 3100 1/2 ton truck.

Do any vendors keep the rebuilt shifter boxes in stock? Apparently, Jim Carter's does not. Thanks

if Carter doesn't have any already rebuilt I doubt anyone does, cores all gone .... but not at all hard to 'rebuild' yourself unless it's really hooped, mostly just needs cleaning out and replacing the seal at top and the spring, if the fork 'U' is noticeably worn [rare] they can be built up with weld and reshaped

Bill

I went though mine myself in June.

I have no idea why anyone would need for one to be "re-built".

The design is pretty robust and simple...there is alost nothing which could go wrong with it.

My vehicle had 215,00 ( or maybe 315,000 ) tough urban miles on it, most of that with Route drivers who were likely unkind in their shifing...and the Shifter Box was about 'Like New' once I cleaned it up and put in fresh Grease.

What is wrong with yours?

It is jamming in 1st gear. I have already replaced all of the bushings on the linkage, and adjusted (and re-adjusted) the linkage at the shift box.

What is happening is, the dog on the shifter column is jumping out of the R-1 fork, inside the shift box, making it impossible to shift out of 1st. You can see what I mean in the picture below:

http://lymanhall.smugmug.com/Trucks/1953-Chevrolet-3100-Truck/i-CFJgbdM/0/L/0815140951-L.jpg

This is what it looks like inside the shift box when it's stuck in 1st. You can see that 1st gear is engaged (top shift fork is moved to the left in the picture) and the dog has dropped down to engage in the 2-3 fork.

Looks to me like the box is worn out, but if anyone has any suggestions, I would be grateful for the help.

can't really see clearly for the grease, but what happens very commonly, is folks get sloppy about following the "H" and at certain points the pawl can get jammed, try concentrating on following the exact H that the box requires and see if jamming goes away

the box doesn't 'wear out', it gets gummed up, the spring breaks, the forks sometimes may get worn down by sloppy shifting, but that can be fixed with some weld - there should be no way the pawl can 'jump out' of a selected position, the thickness of it is greater than the space between the forks

Bill

Can you post an iage of it with no Grease? I can not see anything the way it is.

None the less, I have to suspect the problem is not in the Shift Box, but, is somewhere in the Linkage set-up/adjustment...may be at the Tranmission end.

All the Shift Box does is allow left-right top mode, left-right bottom mode, according to how one is moving the Column Shift Lever.

If the Linkage adjustments are off, the Box may not have full travel of the Dog.

Mine sometimes gets stuck in 3rd Gear...and I am going to look to the Linkage sometime soon.

To get it un-stuck, I have to manually move the Lingake Arm...so, I am still learning, still wrapping my Head around the whole Column Shift set up, but, I am pretty sure my own issue is one of Linkage Adjustment, ( and not the Shift Box ) and I will start at the Transmission and work my way forward, dis-connect the Linkage, see exactly where the two short 'Arms' on the Tranmission want TO be when in Neutral and when in which-ever Gears, and go from there.

I suspect your issue is likewise about Linkage/Arm adjustment rather than internal Box troubles.


The Box itself is so simple and robust, I can not iagine anyhting being amiss, unless there is really outrageous wear and slop or a broken Housing or something.

Here is a better picture, without the grease (previous picture was taken with my cell phone; I was at the side of the road).

http://lymanhall.smugmug.com/Trucks/1953-Chevrolet-3100-Truck/i-fc4rDLw/0/L/Box1-L.jpg

From the position of the levers, you can see the transmission is in 1st gear, but the pawl has slipped down to the 2-3 fork, making it impossible to shift out of 1st. Numerous re-adjstments of the arms at the shift box have failed to cure the problem, which is why I believe the problem lies with the box itself.

Also, I have about .015" radial play between the rod and the box (up-and-down play). I don't know what the wear limit would be on these. There is no axial play to speak of.

very common problem with this setup, don't need to open the box for a roadside 'fix', just need to pull the arms back into alignment, although you need to be on flat ground or have someone holding in the clutch

the adjustment is off, there should be no way for things to get in that position - where the pawl is in that pic is really 'neutral' with no gear selected, it happened because the shifting was a bit "casual", and if the rod joints are adjusted right the pawl wouldn't be able to slip into the slot, it would hit the fork top

there should be no play to speak of in any direction in those joints, probably need bronze bushings, preferable to rubber, same for the joints at the trans - bronze bushings for hinge pins fit, on the "Help!" rack #38374 at FLAPS - and when you adjust the top ends of the rods, make sure the trans levers are in the exactly correct position and tight as well

Bill

Is the spring in the shifter box? They break sometimes or are installed incorrectly.

52Carl: The spring is in there and it looked new when I first set up the shifter. It looks to me like the spring is meant to force the two forks apart, or maybe to force the pawl downward toward the 2-3 fork.

This has been a real mystery. Get this solved, and I am done (man, I thought I was done; that'll teach me).

Thanks for getting back to me. I appreciate all the help and suggestions I have gotten from everyone.

Bill, you're right, I've done the manual adjustment on the shift levers, to get me back in neutral by the side of the road, many times. I only took the top off the box to get a picture.


The pawl as you say is in the neutral position in the 2-3 fork. Problem is, the transmission is in 1st gear. Other than adjusting the 'gate' to get neutral alignment on the forks, and adjusting the arms up and down at the box (which I have done several times), is there another adjustment I am somehow missing?


Great suggestions, thanks. I'll check out those bronze bushings for the levers at the transmission, where it doesn't look like there is room for the other type (rubber) bushings to go. I've replaced all the other bushings in the linkage.

Thanks for getting back to me. I greatly appreciate the suggestions and advice, I've never owned one of these trucks before.

no other adjustments, just learning the feel when you're shifting, you can't take a 'straight shot' from 1st to 2nd, and can't make a "U" from 3rd to 1st, you need to keep to the squared "H" all the time - visualize that box and how things move, here you're in neutral, but the pawl is in the 2nd/3rd fork, held down by the spring - to get to 1st or reverse it needs to move straight up [against spring pressure] before anything, then it can move the pawl, and once it does, it can't drop back into the other fork, especially if you're holding the pressure against the spring .... but, in your pic it does look like the inside corners of the 2/3 fork are rounded a bit, indicating long term sloppy shifting, it may be that you need to get a spot of weld on those ends and file them back square .... also if the trans arms holes aren't quite big enough to take the bronze bushings you can always ream them out enough to make the fit - also make sure the cotter pin cinches the rod in tight, usually you'll need a washer, the more slack at either end of the rods, the more likely the box will jam

Bill

Start at the transmission. Move both levers back and forth and leave both levers in the middle position (neutral). Now look at the shifter box. The Paws/Forks should be perfectly aligned (neutral). If not adjust rods to transmission until the paws in shifter box are perfectly aligned. This is all the adjustments you can make. If the shifter still does not work properly then you have other problems, worn parts, bushings, broken spring, etc.
RdsLessTaken/Don

Start At The Transmission; put both levers in middle position:
http://i1291.photobucket.com/albums...unning%20Boards/IMG_2704_zpscb1dbb8d.jpg

Check Shifter Box For Perfect Paw Alignment:
http://i1291.photobucket.com/albums...nning%20Boards/IMG_80142_zps5e9171f5.jpg

Bill, you are exactly right. Wear on the forks, combined with the too-big gap between the forks, allowed the pawl to drop out of the R-1 fork, hanging it up in 1st.

My friends at the VCCA found me a NOS box:

http://lymanhall.smugmug.com/Trucks/1953-Chevrolet-3100-Truck/i-3PKS4bL/0/M/DSC_1449-M.jpg

I put it in yesterday, and the problem is solved. You can see how crisp the new forks look, compared to the old ones (for clarity, I took the picture before I put grease in the box; it has grease, now).

Thanks everyone for the help and advice.

but don't scrap the old box, it can easily be fixed up ... and don't over grease the box, they're not meant to be 'packed', and the button plug allows light additions occasionally right where it's needed

Bill

There is supposed to be a Spring inside the Shift Box?

Hmmmm...there is none in mine.

Does it make much difference, having one?

yes it makes a difference, the spring keeps a tension on pieces to make for positive movement, you'll be jamming up quite often - see spring here, if it's totally missing someone has had the box apart

Bill