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+--- Thread: Truck doesn’t change gears smoothly (/showthread.php?tid=8289)
Truck doesn’t change gears smoothly - Zocaid - 06-22-2022
Have a 2006 CM870 I don’t know if this is an engine question or a transmission question but on my truck (06 Volvo) when I change gears sometimes it grabs when I go into the next gear. Even though I’m up shifting the truck kind of pulls back like I have downshifted. Even on my best shifts the truck still makes a little movement like it’s just not smooth. You can really feel it Low side and it’s not as bad but can still notice on the high. I have about 15k on a Cm870 long block, 56k on a eaton fuller 10 sp and just got a new turbo and air control box this week. I had these same issues with the previous motor and transmission as well. Any ideas would be appreciated. I’m running out.
RE: Truck doesn’t change gears smoothly - Rawze - 06-22-2022
If you have leaky injectors or if the metering actuators are leaking and worn out, it can be harder then normal to shift, as the engine does not rev down as well as it should when letting off the fuel pedal.
Run an overhead valve adjustment again and then do an injector leak test on it.
http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
A person can also monitor the live fuel flow into the engine to see if it goes to zero mg/stroke while idling.. or fluctuates around up and down like a sign wave. This is an indication that there are issues with a metering actuator.
RE: Truck doesn’t change gears smoothly - Zocaid - 06-22-2022
(06-22-2022 )Rawze Wrote: If you have leaky injectors or if the metering actuators are leaking and worn out, it can be harder then normal to shift, as the engine does not rev down as well as it should when letting off the fuel pedal.
Run an overhead valve adjustment again and then do an injector leak test on it.
http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
A person can also monitor the live fuel flow into the engine to see if it goes to zero mg/stroke while idling.. or fluctuates around up and down like a sign wave. This is an indication that there are issues with a metering actuator.
Thanks! I think I’m leaning toward the actuators. It has done the same thing with two different long blocks. How can I tell which actuator is the one giving me problems. Metering on the outside timing on the inside correct?
RE: Truck doesn’t change gears smoothly - Rawze - 06-22-2022
(06-22-2022 )Zocaid Wrote: Thanks! I think I’m leaning toward the actuators. It has done the same thing with two different long blocks. How can I tell which actuator is the one giving me problems. Metering on the outside timing on the inside correct?
http://rawze.com/forums/showthread.php?tid=110&pid=619#pid619
RE: Cm870 rough shift - tree98 - 02-04-2024
Maybe it's operator error
RE: Cm870 rough shift - Bengy88 - 02-05-2024
Did 870s have progressive shift option?
RE: Truck doesn’t change gears smoothly - Zocaid - 02-05-2024
(02-04-2024 )tree98 Wrote: Maybe it's operator error
I would think that too and I went through thinking it’s me but every other truck I drive is smooth.
My truck Volvo (Cummins cm870) with an eaton 10 spd will not “fall” into gear. It either a. goes in perfect B. goes in and jerks really bad or C. Grinds like a normal missed gear. I have never been able to “tickle” it into gear while the rpm’s are coming down and that’s with 2 motors and 2 transmissions. Could this possibly be shift tower related or is it more ECM/tune related? I’ve changed out pretty much everything on the truck but ECM, wiring harness, CAC, shift tower and a few sensors.
RE: Truck doesn’t change gears smoothly - Zocaid - 02-05-2024
(06-22-2022 )Rawze Wrote: If you have leaky injectors or if the metering actuators are leaking and worn out, it can be harder then normal to shift, as the engine does not rev down as well as it should when letting off the fuel pedal.Hey Rawze,
Run an overhead valve adjustment again and then do an injector leak test on it.
http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
A person can also monitor the live fuel flow into the engine to see if it goes to zero mg/stroke while idling.. or fluctuates around up and down like a sign wave. This is an indication that there are issues with a metering actuator.
I have changed out actuators and I was having power issues that got better. I’m still getting a jerk when it goes in gear. Do you think this it could be shift tower or something in the tune? It’s a white Volvo so I’m sure it has probably had some fleet parameters or something on it. Is there something in the ECM that could mess with your shift like that?
RE: Truck doesn’t change gears smoothly - Rawze - 02-06-2024
(02-05-2024 )Zocaid Wrote: ...
Hey Rawze,
I have changed out actuators and I was having power issues that got better. I’m still getting a jerk when it goes in gear. Do you think this it could be shift tower or something in the tune? It’s a white Volvo so I’m sure it has probably had some fleet parameters or something on it. Is there something in the ECM that could mess with your shift like that?
Without driving it myself, there would be no way tot ell what you exactly are referring to.
if you suspect an ecm program issue and it being a CM870 .. Get with running rough on here... Put the factory program in it temporarily to see if it clears up... then have it re-flashed back when you are sure it is not the program.