MFWD shudder

[kwolfe]

My bx1500 has 111hrs on it. I was using the box blade blade and FEL yesterday and noticed a vibration when driving in 4wd. I looked down and the front axle and seemed to notice that it was shuttering a little.

When using the box blade, I dod not notice the vibration. Only noticed it when I was moving loads of dirt to the dump pile in the back of my property.

When I switch back to 2wd, the unit drove smooth. I have check the fluid level in the front and it is fine.

I need some help.

 

[thatguy]

What is when you were turning (normal due to the different speeds the wheels turn) or when going straight? How heavy of a load - could it be to much weight on the front end?

How hard was the surface you are driving on? The reason they say use 4wd on soft ground is so that it can slip..

good luck

Brian

 

[kwolfe]

I was going straight riding on grass. I happened with the bucket full and empty, low or high gear.

 

[kwolfe]

Anyone else???

114 views and only one response? Take a guess, I don't mind.

 

[art]

I'd be looking at the coupler for the driveshaft, I'd be looking at the air pressure to see if the fronts are possibly to hard and the rears to soft. Does it do it any less on grass then pavement?

 

[kwolfe]

Art,
I measured the tire pressure this morning. Both rears are at 20psi. Front right = 18psi, and front left = 20psi. I did not try taking it on pavement, however I am going to try and take off the loader and see how it works without the extra weight up front.

I looked at the front end of the drive shaft and the U-Joionts last night. Everthing looks OK. The short shaft that goes from the mid point of the tractor to the front U-Joint did seem to have a little wiggle in it, but the notching on the shaft end did not look worn.

 

[ejnichol]

If you can securely lift it off the tires and have someone accelerate and run it at different speeds while you look underneath and see if any visual clues appear.

 

[rbargeron]

.....114 views and only one response? Take a guess....

Here are some guesses - any chance it has always done this and it wasn't noticed until recently? Shuddering without other internal noise points to some major connecting point having too much play. If the front driveshaft has u-joints, they have natural fluctuation in angular velocity. It would show up under load and with misalignment - if some part of the system is loose, it can shudder at 2x driveshaft rpm. If a shaft has u-joints at both ends, it runs smoother if the joints are phased. I would take a look at the main front axle pivot in the center - see if it all seems assembled correctly and doesn't wobble in the pivot. Well, you asked for guesses - If a spacer behind the front drive pinion gear is missing, the gear would be under-engaged and would be "hopping" from tooth to tooth on the ring gear - that would shudder under load - faster than a shaft joint problem.

 

[art]

I don't know what you are carrying for rear weight but I'd let the rear tires down to 10 lbs and see if you still have it or if it alters it.

 

[kwolfe]

I took the FEL off todays and tried the 4wd in the same spot. I could feel the 4wd, but bo shudder. I do have turfs, however, the dirt and grass I have been driving across is very firm. I guess I should only put it into 4wd drive when loading the FEL, then take it out for transport. I am going to also try adjusting the tire pressure as well.