Hard or impossible shifting out of 4x4 with C60 CMP- Tip

[Phil Waterman]

First I know that this topic has been discussed in the past (I can’t find the thread) but thought it would be worth bring up again.

Problem – C60 series Pattern 12 or 13 at times are very hard or impossible to shift out of four wheel drive they shift in easily and shift through neutral, 4 high, 4 low, and PTO without difficult (or with gentle rocking the truck). First assumption is the axles are just loaded; jack up one wheel should release that, problem still there. Yes, of course I adjusted all the linkages when I assembled the truck.

After puzzling on this for a while I realized that it had nothing to do with transfer case it purely is a problem in the shift tower lever end not traveling far enough to go through the gate to allow it to the full over (to the left) and back position of two wheel drive.

Solution- Disconnect linkage shaft #13 by removing the rear pin note, the alignment of the pin to the lever #14. Now see if the transfer shift lever will move to the full over and to the rear of the correct two wheel drive position. Now push the engagement rod #16 all the way in till you feel it engage the ball and spring detent. Examine to see if the pin and linkage will easily line up now, if not readjust the clevis until it is a nice smooth fit.

Why did it change from original set up to now, I suspect a couple of things, one the cross shaft for this linkage is bolted to the transmission so any slop in mounting holes and bolts will allow the unit to shift, another suspect is as the engine and transmission are bolted to the frame with only 4 bolts where any shift forward or aft will affect the clutch adjustment and the two or four wheel drive linkage adjustment.

I note this shifting problem recently when I started using my `41 C60L Pat 12 to haul wood out of the woods over rough ground. At first figured is was the drive train loading, but once I readjusted the transfer linkage it now shifts easily in out of 4x4 hi or low and back to 2x4 drive.

Moral of the story - Just because you adjusted it once by the book doesn’t mean it is right.

[Phil Waterman]

Well a full week of using my C60L in the woods to gather in fire wood and I can report that getting the adjustment correct really makes shifting in and out of Four Wheel Drive, high/low, and into and out of PTO for the winch a breeze.

I can also see why CMPs found homes as working woods trucks when surplussed, either dragging logs or winching trees out of the woods they are just amazing.

Cheers

[Ganmain Tony]

I for one found this very interesting reading Phil. Thanks for sharing.

I do have a problem with my 2WD/4WD engagement. I suspect it's with the ball, spring and detent on the shaft into the trans case. Have yet to sort it out.

Again, great information, thankyou.

[Bob Carriere]

One adjustment is never enough.

I have readjusted my linkages at least on 3 major adjustment/occasions. Each time it ran well until I bounced around the back field and then "a" shifting problem would show up........

Phil's point that components do shift as we drive them and in the linkages-s-s-s as there are many..... do require tweaking...... I suspect this will never completely disappear....

Once you factor in the frame twist, oval (worn) bolt holes, the many loose pins, yoke, clevis connections it really becomes an art in itself to get it just right.

My particular problem was at the middle linkage ....item 17 in Phil's drawing. That particular rod coming out of the T case is adjusted by screwing in or out..... matching the ball detent ,... and matching the shifting rod inside the tower...... I had to remove the shifting hi-lo-winch lever so many times I could do it blind folded....... (Will come in handy if I break down in the bush one day)..... looking down the greasy hole with a flashlight to see how the gates/rods lined up..... so my middle rod needed adjustment....

So here was my headache.... that little item 17 will not come out without dropping the Tcase..... which is a bitch.... I did it once.... and modified the item 17 which has solid pins coming out of opposite side by fabricating a new one using bolts and lock nuts...... it sure came in handy when my earlier second adjustment needed more tweaking.... I was able to remove item 17 in a matter of minutes.... give it a few twist more and re-instal. The job really is a two man job ... me underneath adjusting slowly and Grant on top with a flashight telling me if I was moving in the right direction and how much was enough.....

For the time being it is working fine...... and I can actually now find reverse the first time I need it...... and shift the 2 to 4 and hi-low winch lever quite well as long as I have a mental picture of the peculiar shift pattern.... I guess that explains why they all had a brass shift plate prominently displayed.

None of these two levers will ever ...ever...compete for fast shifting like a Hurst shifter...!!!

My latest nightmare is finding the right spring tension on the throttle linkage to keep me from lurching back and forth when my foot bounces on the gas button when driving in the field.... the truck behaves like a frog when by big boot punches the gas..... maybe it is just an French ethnic thing...!!!!

How many spring are you using Phil...? How hard does it have to be..?
...oh no it getting worst....

Boob

[Phil Waterman]

Hi Bob

You asked some good questions added some observations. One of the things I've done is made up a cheat sheet which shows where all of the linkages should be for each of the modes, this lets me use a big screw driver to shift it into the correct location when everything else fails.

I really suspect the culprit in my case was a very minor movement of the bracket for the linkage cross shaft. Now that I got adjustment it right again it really works good, and I've been racking the truck around on rough ground.

Though I do remember seeing an old hot rod tip about adding a pair of thrust struts between the engine and frame to keep the engine from moving when stronger clutches are installed to cut down on clutch chatter.

From your test drive video it looks like you have been really twisting your truck around too. Maybe it will sort of settle into a good position and allow adjustment the to work.

Now to your question about the throttle springs best fix the yo-yo throttle was the original one being under powered enough that you just put your foot hard on the floor. But yes it does require a fairly hard spring pull. Like the original I used two springs but I had to try several different ones each a little stronger until I found two that worked.

Cheers Phil

[Bob Carriere]

HI Phil

I grafted the 216 pivot stud and the 216 bellcrank onto the 261..... reason being they were of different size and parts could not be interchanged. since the 261 block did not have the forward stud for the 2 springs I fabricated a small plate which bolts on the 216 using existing treaded holes.... and installed two springs like the 216..... then added another return spring from the bottom connection of the carb linkage dwon to a clip attached to one of the bolts on the oil pan...... this is a common connection on late 58/59 Chev trucks...... also added one ahead of the floor toe board...... all in an attempt to hold back on linkage slop........... and I guess that colecctively they are still tooooo soft.

Now you raise an interesting point..... with a 216 you could probably stomp the gas pedal to the floor and the motor would react a lot slower...... the 261 tends to pick up the revs immediately. I drove M37 for quite a while and except when starting from dead stop in most cases you would floor the gas pedal and the engine would spool up slowly. on rough roads you selected an appropriate gear hi-lo range and floor it hanging on the steering wheel.... engine was always controlled by the governor anyways.

I am now wondering if the angle of my foot.... seat position..... is not too acute in the cab 11/12 configeration..... the seating position in a M37 is much more comfortable.... more erect... with thighs almost parallel to the floor.... in the cab 11 with my long legs and sitting low my knees are actually higher than my hips......

So what do I modify.... the truck or the old guy...?

By the way..... I am waiting for a freshly rebuilt Carter YF 735s from the Oaks brothers in TO..... I had queried them when I had my leaking Rochester issue.
Well out of the blue they followed up with me.... just like the good old days when the owner really cared about business. The carb in question will be totally rebuilt and chromated the NOS yellow green color. According to specs it was used as a replacement aftermarket on 261.... same bolt pattern and will accept the original air cleaner..... The carb is vented differently and should not leak..... only time, test will tell....

One more question..... on the 261 the stock vacuum connections coming off the side of the intake manifold will seriously interfere with the engine cover. Mine has a 1/2 pipe thread six sided huge brass fitting..... which I will need to remove and relocate...... I am scared stiff of drilling a hole in the intake manifold somewhere else..... one is I might mess it up.... or filings from the tapping/drilling will drop in the intake..... not really interested in removing and reinstalling the manifolds.... tell me there is an easier way... lazy way.... what did you do on yours..... ? I do have spare manifolds in case of a disaster....

Bob

[Phil Waterman]

Hi Bob

To your last point about the Vacuum Attachment point on 261 manifold in your Pat 11, look at the pictures below. In the picture of my 261 in the Pat 13 you can see that there is enough room for the side of the manifold. In the second picture you see the original 216 set up in Beauty which I think might be a solution for you. The vacuum for the brake booster comes off a spacer place between the carb and the manifold. Of course you would have to make a special one as the throat size and bolt spacing are different. An aluminum plate may be 5/8 or 3/4 thick would let you tap in with the vacuum facing straight back.

Cheers Phil

[Bob Carriere]

Will see if I can find some soft metal to work with....... will visit COHEN & COHEN to see if I can find a slab of brass or copper....not to keen on using aluminium as it can be hard to grind and I can't welded it..

I have a solid slice off a 8 inch Berylium bar from NRC..... but apparently it is very toxic when you machine or grind.....

I like the idea of a spacer........

Bob C.