Excessive off road wheel hop

[DoubleFrame]

I have several dump trucks (Granite E7 350/ EF 8LL/ 4.30 ratio/ Hendrickson suspension) and a couple of AI 400/ maxi torque T310/ 4.17 ratio/ camelback. I’m having trouble with my trucks getting stuck a lot, we are in Florida so the dirt here is sandy. When drivers go off road the trucks start bouncing as soon as it hits a soft spot and we watch other trucks go by without any issues. We have tried the mud and snow button (ATC) and the Off Road button, power divider. Tried driving in low gears, higher gears and the trucks still bounce like crazy like it’s trying to get traction but it can’t so all it does is hops until it gets traction again. I’ve asked drivers to just get pulled out by the dozer or loader as I’m afraid they will break something. I’m not sure what else to do so I’m coming on here to ask for your recommendations. What are we doing wrong? What can we do different to prevent the wheel hop or to get traction? Thanks 

Edited October 14, 2022 by DoubleFrame

[Onyx610]

This one has my interest! 

[Joey Mack]

how many trucks do it?  are there other hired trucks that are doing the same thing?  Is it just because you are on sand?  empty or loaded, or either? jojo

[Swishy]

Some things th@ might 

<1> Spread on tandem drive

<2> Too much weight on steers

<3> Tyre air pressure

<4> Try higher gear and cruise in on site

<5> Use lower gear with lotsa revs on site

<6> check tandem drive suspension for ease of osillation

<7> Parrallel tracking (look along the walls of tyres}

 

A pic of the beast could help

With thanx

cya

[fjh]

5 hours ago, DoubleFrame said:

I have several dump trucks (Granite E7 350/ EF 8LL/ 4.30 ratio/ Hendrickson suspension) and a couple of AI 400/ maxi torque T310/ 4.17 ratio/ camelback. I’m having trouble with my trucks getting stuck a lot, we are in Florida so the dirt here is sandy. When drivers go off road the trucks start bouncing as soon as it hits a soft spot and we watch other trucks go by without any issues. We have tried the mud and snow button (ATC) and the Off Road button, power divider. Tried driving in low gears, higher gears and the trucks still bounce like crazy like it’s trying to get traction but it can’t so all it does is hops until it gets traction again. I’ve asked drivers to just get pulled out by the dozer or loader as I’m afraid they will break something. I’m not sure what else to do so I’m coming on here to ask for your recommendations. What are we doing wrong? What can we do different to prevent the wheel hop or to get traction? Thanks 

If you have rubber frame to diff torque rods try removing them for a day see if this helps! We had customers that said removing these made a world of difference traction wise on dump trucks ! That said Mack at one point offered sealed grease torque rods on certain models MR maybe that had few issues on garbage packers may be an alternative! ! Maybe give it a try! If you have two remove one or both to try it! the down fall being the suspension will dog track some on turns! 

Just something to try!

[DoubleFrame]

15 hours ago, Joey Mack said:

how many trucks do it?  are there other hired trucks that are doing the same thing?  Is it just because you are on sand?  empty or loaded, or either? jojo

All of my trucks do it, I don’t see many hired trucks with this issue. It’s worst when empty. 

[Joey Mack]

do you engage the power divider before you get on the sand, or after wheel hop starts? 

[DoubleFrame]

15 hours ago, Swishy said:

Some things th@ might 

<1> Spread on tandem drive

<2> Too much weight on steers

<3> Tyre air pressure

<4> Try higher gear and cruise in on site

<5> Use lower gear with lotsa revs on site

<6> check tandem drive suspension for ease of osillation

<7> Parrallel tracking (look along the walls of tyres}

 

A pic of the beast could help

With thanx

cya

Thanks for the response, I’ll look at those details this weekend.

here are some pictures of the trucks

[DoubleFrame]

13 hours ago, fjh said:

If you have rubber frame to diff torque rods try removing them for a day see if this helps! We had customers that said removing these made a world of difference traction wise on dump trucks ! That said Mack at one point offered sealed grease torque rods on certain models MR maybe that had few issues on garbage packers may be an alternative! ! Maybe give it a try! If you have two remove one or both to try it! the down fall being the suspension will dog track some on turns! 

Just something to try!

This is a common denominator, they all have the diff to frame torque rods on the Rear Rear. I’ll definitely try removing them on a couple of trucks.

[DoubleFrame]

6 minutes ago, Joey Mack said:

do you engage the power divider before you get on the sand, or after wheel hop starts? 

Power divider is engaged before 

[Joey Mack]

are you able to reach in by hand and move the box rubbers at the ends of the springs? if so, they are worn out.  also look and see if the 'twinkies' are in the boxes at the sides of the spring ends..  

[Swishy]

<8> Try transferring more weight to the drives by raising the pusher axle (or vice versa)

Nice lookn Macks

cya

 

[tjc transport]

#1:  pusher axle MUST BE UP before going any way near sand of loose material. 

#2:  the more power, the more hop. use 2nd gear, NO THROTTLE, and feather the clutch.

#3: steering wheel straight!!!

[The Rubber Duck 006]

Almost sounds to me like the power divider isn't engaging correctly. The dump truck I drove had a system on it that was better than the divider itself. It was almost like a Transfer case that was air activated and locked all axles together and allowed the truck to go through just about anything. I can't remember the name of it but it was a full locker system. 

[Mark T]

Don't suppose it could be something like the type of tires you use ????  They look pretty nice, doubt there's anything neglected on the trucks (worn suspensions) 

[theakerstwo]

What makes one hop up and down in sand is if you notice is with air ride its not so bad as with something that has  rocker between the front and rear like a camel back or hendrickson walking beam.This tells me that when one wheel spends in sand the rocker beam will counter react on the other axle with the opposing wheel of the rocker.one wheel goes down and the opposing wheel comes up till it spins in the sand and it goes down.Now i am mixed up.I had a camel back and it was bad in the sand but not so bad with the CH with air.

[DoubleFrame]

On 10/15/2022 at 9:22 AM, Joey Mack said:

are you able to reach in by hand and move the box rubbers at the ends of the springs? if so, they are worn out.  also look and see if the 'twinkies' are in the boxes at the sides of the spring ends..  

can’t move them by hand, I had the camel back suspension redone a couple of years ago. Twinkies are good. 

[DoubleFrame]

20 hours ago, tjc transport said:

#1:  pusher axle MUST BE UP before going any way near sand of loose material. 

#2:  the more power, the more hop. use 2nd gear, NO THROTTLE, and feather the clutch.

#3: steering wheel straight!!!

I’ll try this out this week. 

[DoubleFrame]

20 hours ago, The Rubber Duck 006 said:

Almost sounds to me like the power divider isn't engaging correctly. The dump truck I drove had a system on it that was better than the divider itself. It was almost like a Transfer case that was air activated and locked all axles together and allowed the truck to go through just about anything. I can't remember the name of it but it was a full locker system. 

I also have an automatic with a Hendrickson haulmax suspension that has lockers and I don’t have this issue with that one. 

[DoubleFrame]

20 hours ago, Mark T said:

Don't suppose it could be something like the type of tires you use ????  They look pretty nice, doubt there's anything neglected on the trucks (worn suspensions) 

We use closed shoulder JKTyre JetSteel Indian drive tires at 120 psi. I’m going to put them at 110 psi and see if that helps. 

[tjc transport]

1 hour ago, DoubleFrame said:

I also have an automatic with a Hendrickson haulmax suspension that has lockers and I don’t have this issue with that one. 

same here. the new t880 kenworth with 565 hp cummins and allison trans is almost impossible to get stuck or wheel hop, because put it in gear and go just enough throttle to move. 

the 2005 t800 with C15 cat and 8ll trans would get stuck every time the driver would go near sand. then i would have to spend 10 minutes getting it unstuck. he had a heavy foot and could not comprehend light on the throttle and feather the clutch. 

he would dump the clutch at 1/4 throttle and then floor it. 

[Mark T]

12 minutes ago, tjc transport said:

same here. the new t880 kenworth with 565 hp cummins and allison trans is almost impossible to get stuck or wheel hop, because put it in gear and go just enough throttle to move. 

the 2005 t800 with C15 cat and 8ll trans would get stuck every time the driver would go near sand. then i would have to spend 10 minutes getting it unstuck. he had a heavy foot and could not comprehend light on the throttle and feather the clutch. 

he would dump the clutch at 1/4 throttle and then floor it. 

Some of these newer things have so much off idle torque even feathering the throttle makes an impressive amount of torque.   

[Mark T]

All those trucks in the pictures have the same cab.  Might sound stupid, but cab shocks and the front cab mounts (which often are wiped out) mean a lot. If it gets bouncing a little then gets telegraphed through a guy's leg to the throttle pedal it just makes it all worse.  There are gas shocks available for them and in my opinion are worth the effort of changing.  And let's not even get into the drivers who like the most expensive air seat and then have to sit on the floor with no air in it.  Believe it or not, after thinking about this I remembered the truck in my avatar used to be able to go under 8 MPH on the switch in the dash (like if it had the idle kicked up)  the other ones wouldn't do it. But I remember it helped in situations like you're describing.  (that truck had Hendrickson RTE) 

[Joey Mack]

I was wondering, after reading all of the posts on this issue..   Lots of good ideas, but what if he lowered his tire pressure from 120 to 95 PSI??  mabey the hard tires spin too easy??   Just a thought..  

[tjc transport]

120 lbs, or 50 lbs. makes no difference. it is all in the amount of power applied.