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Author Topic: truck running really rough from 45-50mph  (Read 5816 times)

Offline BackCountry

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truck running really rough from 45-50mph
« on: April 16, 2014, 07:48:45 pm »
truck running really rough from 45-50mph. doesn't do it before or after and doesn't feel alignment or tire related. Someone suggested torque converter. does this sound right? any other ideas? At this point 100 is a lot to spend if I'm wrong  :-\

1985 k10 with a 305

thanks all
« Last Edit: April 16, 2014, 07:51:02 pm by BackCountry »
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Offline SomeTexan

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Re: truck running really rough from 45-50mph
« Reply #1 on: April 16, 2014, 08:07:47 pm »
All the u-joints good?
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Offline bd

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Re: truck running really rough from 45-50mph
« Reply #2 on: April 16, 2014, 08:18:33 pm »
Did it start all of a sudden?  Any possibility you threw a wheel weight?  Does it change any with brake application?  Does the vibration quit if you shift the transmission into neutral and let the engine idle down at 45 - 50 MPH? 
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Rich
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Offline BackCountry

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Re: truck running really rough from 45-50mph
« Reply #3 on: April 17, 2014, 06:20:23 am »
not sure about the U-joints but it didn't start all of a sudden, it's been like that since i got the truck about a month and a half ago. I'll check the shift into N and brake application tonight when I get home. (wife uses it to take the kids to school during the day, my commute's too long for a gas guzzler  ;D )

And I don't think it's wheel related. I've felt/dealt with that shimmy before and this just doesn't feel like that, but as usual I could be wrong.
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Offline bake74

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Re: truck running really rough from 45-50mph
« Reply #4 on: April 17, 2014, 07:37:33 am »
      As what BD said, it also could be the front rotor's, I have a expedition that did the same thing between 45 - 50 mph only.  Could not fix it until I changed out the rotors.  The front rotors had warped and for some reason it only had the vibration between those speeds.
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Offline BackCountry

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Re: truck running really rough from 45-50mph
« Reply #5 on: April 17, 2014, 07:50:04 am »
good to know. I'll definitely check it out. cause it wouldn't suprise me. but nothing with this truck would at this point lol
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Offline Irish_Alley

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Re: truck running really rough from 45-50mph
« Reply #6 on: April 17, 2014, 10:57:48 pm »
when you say rough do you mean a mis or vibration
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Offline BackCountry

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Re: truck running really rough from 45-50mph
« Reply #7 on: April 18, 2014, 07:32:22 am »
honestly, it doesn't feel like a 'miss'. but it doesn't feel like vibration either, at least not vibration from tires, but it's very jerky. I guess that's the best way I can describe it.
« Last Edit: April 18, 2014, 09:18:20 am by BackCountry »
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Online zieg85

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Re: truck running really rough from 45-50mph
« Reply #8 on: April 18, 2014, 07:42:24 am »
A frozen u-joint will do that.  Add a load in the bed to make the truck squat a bit and see if the vibration goes away.
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Offline BackCountry

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Re: truck running really rough from 45-50mph
« Reply #9 on: April 22, 2014, 06:24:28 am »
ok, so I've noticed a couple of things. first, applying the brakes doesn't stop it and it doesn't happen in drive, only overdrive.
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Offline bd

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Re: truck running really rough from 45-50mph
« Reply #10 on: April 22, 2014, 08:29:27 am »
Do you feel it in the steering?  What's the RPM range of the engine when you feel the 'roughness' at 45-50 MPH?  Can you duplicate the roughness in other gears at similar engine RPM?
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline BackCountry

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Re: truck running really rough from 45-50mph
« Reply #11 on: April 23, 2014, 06:25:01 am »
I feel it all over, it's pretty forceful. like someone grabbing you by the shoulders and shaking lol. but I had it up to 55 in drive and it didn't do it at all. rpm's are hard to say as I don't have a tach, just an ear and it's an auto
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