# Challenger MT555B



## dhalsey5 (Feb 23, 2016)

I would like to ask a question of the group about some problems I am having with my MT555B. I recently had all the injectors and glow plugs replaced now when the tractor gets warmed up it "cams" or surges mainly at low RPMs. The dealer is telling me I need a new injection pump now, does this sound right?

Also, the dealer installed a new clutch slave cylinder and now the tractor lunges forward or reverse, before it changes direction, when using the clutch and shuttle lever. 

Let me know your thoughts.


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## HarveyW (Sep 15, 2014)

Hello dhalsey5, welcome to the tractor forum.

As far as the surging goes, the governor is built into the injection pump, so I guess I would learn to live with it until you cannot tolerate it any longer. Maybe idle it higher, or shut it off? 

The clutch slave cylinder is simply that...a slave cylinder. It is your hydraulic source to the cylinder that is causing your problem.


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## RC Wells (Dec 26, 2008)

From your post I conclude you have the AutoPower IV transmission with the power shuttle. If that is the case you should not need to use your foot clutch when shuttling in the lower ranges. When you press the foot clutch you create a lag as the manual clutch engages, then the hydraulic shuttle will engage afterwards, resulting in a jerk. Also always use your foot throttle and let off the throttle when shuttling, or you will lurch and burn out both clutches prematurely.

The Cat engine you have has an idler gear in the timing gear train which has a bronzed bushing in it with an oil hole drilled through it to allow oil to lube the bushing. If the bushing is excessively worn it allows the gear to drop on the shaft during idle and affects the timing making the engine run rough during idle.

When the engine is revved the bushing centers itself on the shaft and corrects the timing so the engine sounds and runs okay at fast idle.

Pull the timing case and inspect that idler gear for excessive play. If sloppy, replace and your engine will run like a clock.


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