Reverse-Crawler Gear Shifting Fork is Breaking

Sounds like you have a new operator?

Seriously tho but in last one month there has been almost 30 nos. you cannot possibly repair one truck 30 times in one month, so I am guessing you are responsible for many trucks.

Are they all the same age (hours)? Is this the new truck from AMW? Only been on the street for a year or two? Were the drivers experienced before they got new trucks? Ride along and see if they are trying to get into reverse before the transmission slows down.

Otherwise I would suspect the fork for the reverse was under-designed and I'd be talking about warranty with the seller.

Hi,

ZF is strictly denying the fact of replacing in warranty,they are saying that drivers are not skilled and they are engaging reverse gear while vehicle is in motion,but i am not convinced with them,because when we dismantle the gear box the reverse-Crawler Fork was in Totally engaged position,and there were very slight rubbing marks on Sleeve teeth.

Regards,

James J

Do you have extra training for your drivers on how to engage a non-synchromeshed gear? If not (do you know yourself???) the ZF is correct in what they say.

I started driving when "SOME" cars had synchro on 2nd, 3rd and 4th, but not on 1st or reverse, you do need to learn how to properly engage the gears.

Your wear findings meant nothing to me till this question is correctly answered!!!

I suspect that your drivers are the problem if any are under 60 years old!!!

Hi Andy,

Thanks for ur reply,I Know in order to engage a gear which is not synchronised we have to do double de-clutching,But when i asked those drivers they said they are following this habit.

What do u say it may be because of the poor Gear shiting mechanism?

Dear James J.

The 2523 tipper is designed for mining applications. Asia MotorWorks launches tipper Features 235 hp Cummins engine and a 9-speed ZF gearbox, which is unique in India. also used in Stralis Light Weight Tractor Massif, Daily 4x4 Iveco LMV Iveco at Hanover IAA Commercial Vehicles 2008.

I take it this is mining equipment worked hard everyday. Number of events can cause bent forks in transmission. One being the clutch is not adjusted to a proper set. It is not releasing or disengaging from the transmission. The trans keeps turning while the operator is trying to put it in the reverse direction or take out of gear. Most likely with a load in the bucket. Could be a cause ? In highway equipment they put in clutch brake for stop the shaft from turning monetarily to put in a gear.

Next is Motor and or transmission mount is broken, cracked in the frame . When there is a load on, this added weight puts extra presser on the shift tower, shifting rods to the transmission and shifting shift in the transmission. The operator has to force the shift, it is not a smooth easy shift. Forcing gears will bend or break something while it is operator error it is also a manufacture defect. The defect is in the nature of close tolerances for the controls. In other words no room for slop.

I would say try putting a load on. Try turning and putting in reverse at the same time and see if the shift tower binds up. I may not even be close to the cause.

Last is the shifting forks are being made with the wrong steel. The steel or cast is weak or springy and bends easy. You may need to reinforce the forks by welding a strip on each side of the fork or use hard plate welding rod to hard plate the sides of the forks to keep them from being bent. I am assuming you have a repair shop with mechanics, on site engineers and equipment dealer representatives to help find cause and a effective repair solution as this is an on hands on site fix.

good luck you are talking costly repairs on high dollar equipment. everett w.

I'm surprised that there seems to be no support for these units. Thirty failures in a month indicate a strong problem. ZF should be willing to look into this regardless of warranty. Do a Prado on this problem. Are the drivers upset about some management change?

It is very unlikely that there is a problem with the ZF unit but not to be ruled out. Independent metallurgical analysis of a fork should rule out or in favor of part failure. I'm sure that you knew all of this though.

We've had vendors forget to heat treat parts before.

Hi Everett,

How you doing?Thanks for your valuable suggestions,i would like to throw some more light for your better understanding of this acute problem.

1. We mount Gear Box onto the rear of Flywheel Housing of engine by bolts,There is no other such support to the gear box,Its a kind of Overhanging beam for Engine.

2.The Gear Shifting Mechanism is Mechanical,With One Link rod used for Gear Engagement and another one for gate selection,the Motion of link rod for gate selection is transferred to Gear Shift Outer lever of gear box with the help of Reaction rod.

I have a doubt that Sometime because of the improper length of the link rod free length from ball joint center to center,the link rod is hitting to some foreign parts in its path causing Reverse gear gate selection not achieved.

Please Help me out.

Regards,

James J

I would check to see that the shift linkage is not being bound or pressured while driving but not shifting. Frame flex or lack of +/- clearance in the linkage could cause force on the fork in otherwise steady-state conditions.

I would also look at the fracture site to see if I could determine what direction the inappropriate load came from. This might put you on the path to finding the cause.

Also, is there excessive play in the shaft that the fork is engaging. Shaft movement could cause the fracture just like fork movement.

Is this shift position held in place by detents? I would be inspecting them for proper function.

If this is a weak link, I would put out an edict that all operators must come to a full stop, push in the clutch and wait for everything to "wind down" before engaging reverse. This is not a fix but if failures drop, it gives you an indication.

Is clutch disengagement complete enough that the input side of the transmission can come to a complete stop when the vehicle is stopped? Hopefully the operators don't have to "crash it" into reverse. Do the shift dogs indicate they are doing this?

Dear james j.

could you post pictures or the equipment, the linkege and trans hook up. Maybe an over all picture. This will help all who are interseted see the problem we may beable to have abetter idea of how to fix.

Everett w.

Dear Friend,

I have made a powerpoint Presentation about this problem but i have not been able to upload that here,can u plz help in this?

Regards,

James J

sEND ME MAIL ID or phone to discuss or forward detail

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Regards,

James J