Triplex Quandry!

[Draggin8]

Hello, everyone! I've had an account here for a couple of years, and I've enjoyed following the discussions. Thank you for the informative reading.

Now I'm stuck - and it's my own fault. But I'm hoping for some constructive suggestions.

I'm restoring a '59 Mack H653LT with a Triplex transmission. The truck hadn't run for five years or so, when I bought it, in September 2015. I got it running during the Spring of 2017 - that's a story in itself. But it runs great. I've been able to drive it short distances, though I soon determined that the 5-speed was stuck in 2nd, and the 3-speed was stuck in Direct.

Everything was so caked with grease and dirt I couldn't see much, but that clued me that the time had come for some serious clean-up. Got the chassis and underside of cab stripped clean by a friend with "dustless blasting" equipment, this past September. Painted all exposed metal with flat black chassis primer, and moved on.

Both shift levers were badly worn - slotted hole for pivot augured out, pivot pin necked down. A friend tidied them up by TIG-welding replacement metal into the holes and then milling them back to original slot dimensions on his Bridgeport. He even furnished a pair of hardened pins - a complete success. But that's when I discovered that the mechanisms actuated by the shift levers were bound up, due to rust and dirt-packed grease, external to the gearboxes themselves. I got the 5-speed section cleaned up and working smoothly, and then tackled the 3-speed (For anyone not familiar with the geography, that's the portion at the right-hand side in the "TriPlex" photo.)

Based on my experience with the 5-speed, I imagined that the actuator shafts were bound up. These enter the 3-speed at its "lower-left corner" in the photo. After talking with an actual mechanic (not a "hobbyist" like myself) I got up the courage to remove the top cover - simple as pie. No problem. You can see it upside down on my bench, in the "TopCover" photo.

Over a weekend, I dosed the shafts a bunch of times with penetrating oil ("Aero Kroil") and finally they began to free-up. In fact, things were going so well, before I knew it, I'd managed to pull one of the shafts nearly all the way out of the housing! I wanted to inspect it - and also the "detent" mechanism, which seemed way too stiff (Worn out?). And this is where I made the mistake that put me in my "Quandry" - As I attempted to remove the shaft from the case, I inadvertently rotated it to the point where the detent mechanism (ball-and-spring?) found its way into the milled slot near the end of the shaft. (You can see it, if you zoom in on the upper right-hand corner of the "TopCover" photo).

Now the shaft is trapped! I can move it in or out about an inch - until I hit the end of the slot. I can rotate the shaft either direction - until the flat side of the slot runs up against the "ball" - or whatever it is.

Can someone give me the number of the nearest "Triplexes-R-Us" so I can pick up another set of parts? Oh .... No? That's what I thought!

So my "Quandry": The parts I have are irreplaceable! I don't want to risk damaging anything - but I do want to continue making progress.

What should I do?

Thanks in advance!

-Doug-  (The Draggin thing is a nickname from another life!)

[carlotpilot]

don`t give up there had  to be a way to get that ball & spring in the housing to start with and hold it there while the shaft was slid in.  a reverse op should get t out   just have to figure out how  perhaps a very strong  magnet and some jiggiling around will pull the pieces back into the hole they belong in far enough to let the shaft out or turn out of the slot      worth a try  there are some really potent little magnets around

[Lmackattack]

I have no first hand experience working with the detent of this top cover but I do know with other gear boxes that you have alot of leverage when using the gear stick. what seams tight by hand will be easy when moving the stick thru the detent. Are you sure you cant force the detent back up in the housing by hitting the rail with a dead blow hammer or by pulling on it with comparable force when using the stick. Reason I say this is that the detent had to get in there before the shaft was put in so it should force the ball up if pulled hard enough.  Unless im missing the something?

[70mackMB]

3 hours ago, Lmackattack said:

Unless im missing the something?

He's not caught in the detent. It is stuck in the cut out at the end of the shaft. The pix of the cover turned over it's the lower shaft. Look at the right end and it is centered about 1.5 inchs from the end.

Doug, Can you put a small bar in the linkage hole and maybe roll the shaft 180'? ............Hippy

[Freightrain]

Ah, I see the notch now.   I'm guessing getting the ball to pop up in the detent hole is going to be tough with that big flat spot on the shaft(no taper to help push it).  The ball is too big to stay in the flat to get past the detent hole in the top.

Hate to say it, but you might have to drill through the top of the casting to let the ball/spring fall out and then drill/tap/plug or weld it shut?

[eddeere]

Sorry I cant help with your problem. That is one neat truck. What is dustlesss  blasting and what are your tires. 

[Freightrain]

I was watching this video recently.

 

[Lmackattack]

3 hours ago, 70mackMB said:

He's not caught in the detent. It is stuck in the cut out at the end of the shaft. The pix of the cover turned over it's the lower shaft. Look at the right end and it is centered about 1.5 inchs from the end.

Doug, Can you put a small bar in the linkage hole and maybe roll the shaft 180'? ............Hippy

Correct. I guess what im trying to say is that the detent ball and spring had to go "home" all the way when the rod was installed in the cover. So in the perfect wrorld the rod should be able to push the detent ball back up as its pulled thru the large notch. (That is unless the bar needs to be turned 180 when ever installed to avoid this issue?) I do wonder if that large notch was large enough for the spring and ball to fall out as he said? only way to get it back in is to turn it upside down an start shaking it while saying a prayer....  I lent my mack book that the museum sent me to a friend, I wonder if it went into detail with top cover repairs?

[Draggin8]

Wow! Thanks to every one of you for the great replies!!

Carlotpilot: I'm going to try your magnet idea, first.

Freightrain: If that doesn't pan out, I think I'll take your "drill/tap/plug" suggestion.

eddeere: Thanks for your enthusiasm over the truck! Tires are by General, supplied by S&S Tire of Puyallup, WA. Front: Grabber OA 385/65 R22.5  Rear: 11R22.5

Freightrain: Yep - that video shows the process. Soon after I bought my truck, I met Brian Vaughn, owner of Classic Reflections (www.classic-reflections.com), an automotive restoration shop near where I live. He has a big trailer-mounted dustless blasting machine, and I hired him to strip the chassis and running gear.

Again - Thank you all for your input. I'll keep you posted!!   -Doug-

[Draggin8]

17 minutes ago, Lmackattack said:

.... (That is unless the bar needs to be turned 180 when ever installed to avoid this issue?) ..... (O)nly way to get it back in is to turn it upside down an start shaking it while saying a prayer.... 

I think this is an important point. If only we'd had the conversation before I let the ball and spring fall down into the notch!

I'll use your idea of prayer along with a strong magnet, and see what happens.

[Draggin8]

3 hours ago, 70mackMB said:

He's not caught in the detent. It is stuck in the cut out at the end of the shaft. The pix of the cover turned over it's the lower shaft. Look at the right end and it is centered about 1.5 inchs from the end.

Doug, Can you put a small bar in the linkage hole and maybe roll the shaft 180'? ............Hippy

Thanks for helping me make my point. Once I've positioned a strong magnet to pull things in the proper direction, I'll try again to rotate the shaft.

[carlotpilot]

 the drill tap and plug method may turn out to be the best choice     no chance of busting the housing   and you wind up with variable detent pressure

Edited December 7, 2017 by carlotpilot

[steve s.]

I agree you have a very cool truck there. Not a common model at all. Before trying the drill and tap method, I would attempt to rotate the shaft back out of the notch. Pulling it straight out won't work because the ball is probably entirely in the notch. But the rotating  shaft might just allow the ball to be pushed back into its hole. Worth a try anyway.  Drilling and tapping is a good last resort for sure. That top cover is not that rare of a part that you can't find another one.  You might not find an aluminum cover, but there are still triplexes around. Good luck.

[70mackMB]

On 12/6/2017 at 9:05 PM, Draggin8 said:

Now the shaft is trapped! I can move it in or out about an inch - until I hit the end of the slot. I can rotate the shaft either direction - until the flat side of the slot runs up against the "ball" - or whatever it is.

How about this?  The ball is loose and floating around in the slot. It is the spring that is holding the shaft in place.

 Hard telling not knowing............Hippy

[Draggin8]

Well, that wasn't too bad. I drilled through the casting, and removed the ball/spring detent from the top. Photos attached ...

[carlotpilot]

that old mack probably has never been in better hands

[Freightrain]

Nice work on the jig set up.  That kept it all in line.  Glad to see it worked out!!!  Just a lil touch of weld and you are back in bidness......

Edited December 21, 2017 by Freightrain

[Maddog13407]

so I missed this, is that shifting fork BROKEN off and welded back together??? imagine that back in the day,''' hey joe we broke this fork off, I called Mack and they want $20 for a new one''  ... ''screw that , that's a whole night of adult beverage down at the Gin Mill, ill weld the sob!''

[57 bcr]

Welcome to BMT! Nice rare daycab! Best of luck to  you! Looks like  you've got the technology!   Al