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Alexp86

https://youtu.be/ZPSTVV_fusU?si=_ChlUazooNKgbgZJ

This has been happening for a few months now, no shop has been able to solve it.
So far the clutch, actuator, carrier bearing, 3 speed sensors on the transmission and accelerator pedal has been changed and it feels like after they just changed the carrier bearin the jumpin shaking has gotten worse.

It happens intermittently which is why I believe the dealers can't solve it. This video is from this morning. After sitting for 48hrs I warmed up the truck placed it in low and moved about 300 feet, set my brakes went to check in at the shipper. When i got back in the truck hit D and boom threw my coffee everywhere. Its been happening mostly in 1st or 2nd gear. If i speed up to 4th, it'll stop until it decides to do it again. It also sometimes happens when i stop at a stop sign or traffic signal. When it goes into 2nd gear ill feel a slight bump then when i start to accelerate it shakes or jumps violently.
When this happens it feels like the accelerator pedal is super sensitive, lately there has been a lag feels like i have to push it further down to start moving even empty, but when this shake happens the slightest touch it makes the truck feel like its on steroids or something, itll move 40k like its nothing.

Also i feel like I need to add that if the truck is parked over a week itll work just fine for about 1000 miles then itll start with the jumping and shaking in 1st or 2nd gear only other gears work just fine.

If anyone can help or has encountered this issue please help me out. I keep taking it to these shops and they just keep replacing parts and nothing seems to help. Took it to 2 peterbilts 1 kenworth and a few local shops who ends up telling me i need dealer... idk what else to do.

Rawze

keep a close eye on the engine rpm. Is it floating around or creeping up?.

What rpm is the engine set at for idle?.

Alexp86

(01-25-2024 )Rawze Wrote: keep a close eye on the engine rpm. Is it floating around or creeping up?.

What rpm is the engine set at for idle?.

When it did it yesterday I did notice on startup it was 1 higher around 8 for about 5 seconds and it dropped. Its normally a hair bellow 7, 690.

Rawze

(01-25-2024 )Alexp86 Wrote:
(01-25-2024 )Rawze Wrote: keep a close eye on the engine rpm. Is it floating around or creeping up?.

What rpm is the engine set at for idle?.

When it did it yesterday I did notice on startup it was 1 higher around 8 for about 5 seconds and it dropped. Its normally a hair bellow 7, 690.

DO an injector leak test on it to see if it will pass.
ref: http://rawze.com/forums/showthread.php?t...3#pid75483

Also, the rpm for most auto-s$itter trannies needs to be below 650rpm for them not to get jumpy and want engage like that.

Engine could be idling up on its own due to leaky injector(s) or the fuel pedal acting up.

Are you letting those idiots at the truck wash places wash under the hood?... That IS A BIG NO-NO!. and will cause the fuel pedal to randomly act up among other problems, especially so on Pete's and KW's.

Alexp86

(01-25-2024 )Rawze Wrote:
(01-25-2024 )Alexp86 Wrote:
(01-25-2024 )Rawze Wrote: keep a close eye on the engine rpm. Is it floating around or creeping up?.

What rpm is the engine set at for idle?.

When it did it yesterday I did notice on startup it was 1 higher around 8 for about 5 seconds and it dropped. Its normally a hair bellow 7, 690.

DO an injector leak test on it to see if it will pass.
ref: http://rawze.com/forums/showthread.php?t...3#pid75483

Also, the rpm for most auto-s$itter trannies needs to be below 650rpm for them not to get jumpy and want engage like that.

Engine could be idling up on its own due to leaky injector(s) or the fuel pedal acting up.

Are you letting those idiots at the truck wash places wash under the hood?... That IS A BIG NO-NO!. and will cause the fuel pedal to randomly act up among other problems, especially so on Pete's and KW's.

Ok I will try that. I just got the software im ordering the cables today. I did lower the rpm to 650, any lower was feeling like it was going to stall, but it didint jump at all today. It could be a coicedence as it doesnt happen everyday, but ever since they changed the carrier bearing the jump has been more violent.
I also cleaned the plugs on the passenger side hopefully it was something that simple.

No ive never let anyone wash my engine although when the wash the truck it drips cause they have the hood up whos to say it didint splash where it wasnt supposed to.

Rawze

(01-25-2024 )Alexp86 Wrote: ...
Ok I will try that. I just got the software im ordering the cables today. I did lower the rpm to 650, any lower was feeling like it was going to stall, but it didint jump at all today. It could be a coicedence as it doesnt happen everyday, but ever since they changed the carrier bearing the jump has been more violent.
I also cleaned the plugs on the passenger side hopefully it was something that simple.

No ive never let anyone wash my engine although when the wash the truck it drips cause they have the hood up whos to say it didint splash where it wasnt supposed to.

If some complete idiot aligned the carrier bearing perfectly to the drive shaft then that could be a serious issue. It is supposed to be off by about 2-3 degrees (and bearing itself angled slightly) to prevent harmonics and drive-line jumping ... and a lot of people who replace them are completely clueless about this, assuming like fools that they are supposed to be in perfect straightness.

Alexp86

(01-26-2024 )Rawze Wrote:
(01-25-2024 )Alexp86 Wrote: ...
Ok I will try that. I just got the software im ordering the cables today. I did lower the rpm to 650, any lower was feeling like it was going to stall, but it didint jump at all today. It could be a coicedence as it doesnt happen everyday, but ever since they changed the carrier bearing the jump has been more violent.
I also cleaned the plugs on the passenger side hopefully it was something that simple.

No ive never let anyone wash my engine although when the wash the truck it drips cause they have the hood up whos to say it didint splash where it wasnt supposed to.

If some complete idiot aligned the carrier bearing perfectly to the drive shaft then that could be a serious issue. It is supposed to be off by about 2-3 degrees (and bearing itself angled slightly) to prevent harmonics and drive-line jumping ... and a lot of people who replace them are completely clueless about this, assuming like fools that they are supposed to be in perfect straightness.

I think they may have it was done at kenworth dealer, after many people told me they had the best transmission guy in the area, thats proving to be wrong as he didint solve anything, but made it 10x worse. I really dont know whatelse to do. maybe time to give this up.

Rawze

(01-27-2024 )Alexp86 Wrote: ...
I think they may have it was done at kenworth dealer, after many people told me they had the best transmission guy in the area, thats proving to be wrong as he didint solve anything, but made it 10x worse. I really dont know whatelse to do. maybe time to give this up.

If it is not aligned properly... and you look at the replacement bearing mount where it bolts up, ... you should be able to see if there are wear marks or scars from its original install vs where it is currently mounted, if its mounting position or angle got moved.

PolishHammer

Service ranger set up check to see what the starting settings are. Yiur engine rpm is too high to begin with. There are different modes to get going there is also hill assist it holds the brakes untill you get going and basically walk threw the mans they release so you don't roll backwards. First thing that a your rpm. Find out why so high ? Then change it with insite to 550 and test. If that doesn't fix it let us know.