PTO question

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Jun 13, 2017 | 08:12 PM

49fordv8f4

Thread Starter

Cargo Master

Joined: Aug 2014

Posts: 2,594

Likes: 72

From: North Central Arkansas

PTO question

As most of you know that have followed my build thread, I changed the T9 spur gear 4 speed for a T98 when I did the Mercedes engine swap. The gear on the cluster gear that drives the PTO is a helical gear. The direction of the helix on the gear has a tendency to kick the PTO out of gear, maybe that is why the helix direction was changed in '56. I can hold light pressure with one or two fingers on the PTO lever as the bed is lifting and it will easily stay in gear. If it was cable operated, I don't think I would have a problem. I am thinking about adding a quadrant and squeeze handle with a lock to the PTO lever to keep it engaged. Does anyone see anything wrong with that idea? The PTO is turning a hydraulic pump, so in theory if it locked up, it could wipe out the transmission. But, a spur gear PTO wouldn't jump out of gear with extreme pressure either. Thoughts?
Thanks, Mark

Jun 13, 2017 | 08:31 PM

raytasch

Believe Nothing

Joined: Jun 2004

Posts: 7,516

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From: W. Central FL.

I would think the small u joints in the PTO driveline would be the weak point, weaker than the T98 gears. The PTO engagement cable had quite a bit of resistance to movement on the PTO in my 56. My guess is, it took a couple pounds effort to move that cable. I would try a cable, mounting it where I could watch the bed come up while my hand was near the cable. Mine was on the left side of the dash. I've seen the ***** on the floor beside the seat.
Edit: My 49 had a dump bed as well but I removed and sold the assembly soon after I bought the truck and I don't remember where the controls were.

Jun 13, 2017 | 09:29 PM

Mixer man

Logistics Pro

Joined: Sep 2014

Posts: 4,920

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From: Bothell & Silverdale, WA

Morse and Teleflex used to make T-handle and **** locking push-pull cables just for that purpose. But liking linear actuators so much, I plan on using one for my PTO.
As far as the weak link goes, I'm not so sure. When I first got my mixer the PTO was hanging by it's output shaft - almost dragging on the ground, and all six mounting studs were broken off, and naturally all the spacers and shims were missing. Strangely enough, the PTO and transmission are in good condition and back in service.

Jun 13, 2017 | 09:41 PM

tinman52

Welder User

Joined: Feb 2009

Posts: 5,269

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From: northwest MT

How about a spring loaded detent....just strong enough spring to keep it engaged, but able to pop out of gear if there is a problem.

Jun 13, 2017 | 09:50 PM

Mixer man

Logistics Pro

Joined: Sep 2014

Posts: 4,920

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From: Bothell & Silverdale, WA

There should be no problem with the hydraulics if they were properly installed. The pump would just go into relief bypass when the cylinder reached the end of it's stroke.

Jun 14, 2017 | 04:41 PM

49fordv8f4

Thread Starter

Cargo Master

Joined: Aug 2014

Posts: 2,594

Likes: 72

From: North Central Arkansas

Thank you for all the replies and ideas. I believe as Ray and Bob mentioned the cable would be the easiest fix and would have enough resistance to hold the PTO in gear. I will probably use a cable as a last resort though, as I would like to keep the lever in the floor if possible. Tinmans idea of a spring loaded detent sounds better than the idea I had of a latch on the handle. I think I will work on the detent idea. I'll let you know how it works out and post pics.
Thanks again all,
Mark