Jump to content

Noisy PTO rattle with MP8's and Allison Auto


Recommended Posts

Hello everyone, I've talked to a few of you before about this problem.  I bought a 2017 GU713 MP8 Allison auto dump truck at the end of last year. The problem I had was the PTO rattle being very loud inside the truck. My dealer had made several attempts to quieten it with no luck.  I know now this is a known issue but today I hit major discovery. Every bit of the sound I was hearing was traveling up my shift or raise/lower cable. The sound is traveling up the cable like a speaker wire and blasting out of my control console.  I remove the cable from the PTO completely, bracket too and no noise what so ever...NONE!

So now, how do I fix this?  I'd love to hear some ideas.  My first thought would be convert to a electronic or air system and eliminate the cable, but I'm not sure whats out there.

Edited by Deere Mack
Link to comment
Share on other sites

I don’t know if it would completely eliminate the noise but we changed out the pto on a truck that had a cable system to an air shift pto and the air shift is 100 tines better. Smoother, faster, easier, cable doesn’t freeze up in winter.

Link to comment
Share on other sites

4 hours ago, RobM626 said:

I don’t know if it would completely eliminate the noise but we changed out the pto on a truck that had a cable system to an air shift pto and the air shift is 100 tines better. Smoother, faster, easier, cable doesn’t freeze up in winter.

I feel like it would make a difference but not sure. I wonder if the air lines could act like fiber optic cables and carry the sound or if it's mainly the vibration from the metal cable carrying the noise.

Anyone out there have the same set up with air controls?

Link to comment
Share on other sites

11 minutes ago, Deere Mack said:

I feel like it would make a difference but not sure. I wonder if the air lines could act like fiber optic cables and carry the sound or if it's mainly the vibration from the metal cable carrying the noise.

Anyone out there have the same set up with air controls?

The air hoses that replaced the cables are hollow plastic 1/4” hoses. The cables obviously have a metal cable with a plastic sheath over them. There’s not really a medium for sound/vibration to travel with the air hoses

Link to comment
Share on other sites

No problem. I can’t gaurantee if it will get rid of your problem but like I said earlier. There’s a night and day difference between the two as far as ease of operation goes. This set up didn’t once freeze up this past winter and it engages the first time every time.

i think the total cost for the pto and air controls costed around 8-900. My in-house mechanic installed it so we didn’t pay labor. I changed out a pto that already had air controls and I paid over 1000 from the mechanic

  • Like 1
Link to comment
Share on other sites

The information below shows how sound travels through different mediums.  Make notice to  steel vs Nylon or Polyethylene. Most air lines are made of nylon or polyethylene and even between the two of those there's a considerable difference. Looks like the polyethylene line wins my vote.

Mild Steel    3235 m/s

Nylon           1150 m/s

Polyethylene  540 m/s

Dry Air (can vary depending on humidity) 346 m/s

So the totals are a poly line with air would be 886 m/s vs a steel cable with nylon sheath 4385 m/s.  The math says the air control hoist valve vs a cable control should be a lot quieter.

🤔

 

Edited by Deere Mack
  • Like 1
Link to comment
Share on other sites

Is the cable for engaging the PTO, or running the pump/hoist up and down.  I myself hate the air operated hoist,  and took it off my truck and replaced with the cable.  The air operated hoist doesn't have the same level of control/feathering  in my experience.  But the air operated pto is the way to go.

Edited by OldRedMack
Didn't finish my thought.
Link to comment
Share on other sites

39 minutes ago, OldRedMack said:

Is the cable for engaging the PTO, or running the pump/hoist up and down.  I myself hate the air operated hoist,  and took it off my truck and replaced with the cable.  The air operated hoist doesn't have the same level of control/feathering  in my experience.  But the air operated pto is the way to go.

It's the control cable for the hoist up & down. My PTO is air operated.  It may be a trade off, feathering capabilities or extremely loud jack hammer sound in cab. 

Don't forget I understand these trucks are known for the PTO rattle with the Allison auto. But the discovery is that it enters the cab through the Hoist control cable.  Remove the cable from the PTO and Bracket, tie it away and no more noise. The only way you'll here it is to roll down your window and hang your head out the cab.

If anyone out there has my setup with air operated hoist control please chime in.  Thanks!

Link to comment
Share on other sites

The setup I had was cable engage/disengage and cable up/down. I absolutely hated it. Now it’s air everything. And the set up is great. I know what you’re saying about the air not being as precise because the regular truck I drive is like that. I feel like the older the valves get they they get loose and leaky and aren’t as precise.

Link to comment
Share on other sites

19 minutes ago, RobM626 said:

The setup I had was cable engage/disengage and cable up/down. I absolutely hated it. Now it’s air everything. And the set up is great. I know what you’re saying about the air not being as precise because the regular truck I drive is like that. I feel like the older the valves get they they get loose and leaky and aren’t as precise.

I'm sure there's a lot to consider, brand, install etc. But I'd be very interested in hearing from someone with the MP8 and Allison auto with the air control.

Link to comment
Share on other sites

4 hours ago, Mackpro said:

I will pass this info on my my buddy who has 3 GU's with MP8/ Allison. I'm pretty sure he has the cable up/down controls. 

If he wants to test it out for himself it will take about 15min to remove the cable completely from the pto & pump, even the line from the bracket so no part of the cable is touching. He'll be amazed,  I swear it was like I was in a different truck.

Link to comment
Share on other sites

Looks like I might make the change, got to see if it makes a difference.  Anyone that has one as loud as mine will understand and hopefully it'll work and help out some other guy down the road.  The air operated hoist control is new to me, I've always had the cable. Is there anything I should know or look for, or is it a just a bad idea for a tri axle dump truck?  Any info would be a help.  Thanks

Link to comment
Share on other sites

Could you get a length of rubber gas line and run the cable through?   It won't eliminate the direct connection between the control lever and pto but may buffer the sound some.  Just a late night idea.   

Link to comment
Share on other sites

8 hours ago, Hobert62 said:

Could you get a length of rubber gas line and run the cable through?   It won't eliminate the direct connection between the control lever and pto but may buffer the sound some.  Just a late night idea.   

Good morning, I appreciate your suggestion. I've tried putting rubber everywhere imaginable. Put rubber o rings in between the pin connection at cable and PTO, thick rubber on and around the cable bracket and in between cable and bracket. I also put extra sound deadening material on the inside of my control tower.  I've been desperate to eliminate this problem.  lol  I think the only way to help with the cable would be to have some type of plastic connection between PTO and cable. Even then sound travels  through hard plastic fairly well.  Installing air shift next week with polyethylene lines, the quietest way to go.

Link to comment
Share on other sites

I would compare going to the air control over cable is like going from mechanical to electric controls on a loader.  Which would mean that a little bit of movement on the stick goes a long way.  Just remind yourself that it is completely different and you will get use to it pretty quickly.  Even though I don't like the air controls, if my truck rattled like what you describe then I would swap it out also.  

Link to comment
Share on other sites

  • 4 weeks later...
  • 2 years later...
  • Deere Mack changed the title to Noisy PTO rattle with MP8's and Allison Auto
2 hours ago, Lema Trucking said:

I am having this problem in my 2021. Its not even 2 months old and im going bat bleep crazy in this cab. 
any update Deere mack? 

Hello, I ended up selling that truck.  The air control made a huge difference but the noise was still there.  It's like that with most Allison's.  Have a friend that just bought a new Pete with the Allison 4700 and it does the same thing.  Some are just worse than others and I've seen some that make very little to no noise.  Good luck!

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...