My 98 Sily K1500 4WD 5.7 has 130,000 miles and still runs like new. I am very fastidious about maintenance and repair.

The truck recently developed a noticeable vibration/shudder that only occurs while I gently accelerate from a stop. The vibration/shudder starts at just off-idle speed is only noticeable briefly, then goes away as speed gets above about 10mph.

If I had to guess, I'd say it feels like it is coming from tranny area.

Any suggestions? I'm guessing driveshaft yoke or u-joint??

thanks for all suggestions.

 

My money is on a U-joint. Check the rearward most U-joint right before the rear diff.

 

U-JOINT.

 

Thanks, I am gonna remove the driveshaft today and check...................

 

Many thanks for the replies. I pulled my rear driveshaft. The rear u-joint is less than a year old and was fine. The front u-joint has a teeny amount of wear. One end of the joint had some small wear ridges, so I replaced it. The yoke looks new, but I greased the splines prior to re-assembly.

Re-installed the driveshaft, but problem not fixed. I still get the vibration between 1,000 and 1,500 rpm, then it goes away. I feel the vibration mostly in the gas pedal with my right foot. It's extremely annoying for stop-and-go driving, which is mostly what I am doing.

If anyone has any suggestions, please post.

Thanks.

 

Check your motor mounts or tranny mounts. Most likely your motor mounts.

 

torque convertor?

 

First, one more question. Does it do it when in park and you rev the motor, also can it stay doing it when you stay at the low speed? Or does it just go away right after it starts? If it doesn't do it when you are in park or in neutral and it goes away right after it starts, then I would have to say either the torque converter it locking and unlocking or, the tranny is trying to shift but not quiet in one or another gear. Kinda shifting back and forth between the gears. It is kinda common when the tranny has electronic controls with a mechanical kick down cable. Those are my thought on the issue. Good luck.

 

Well, I found my vibration and wanted to post here. I mostly felt the vibration through the gas pedal.

I replaced one u-joint (the other was new), but that did not fix it.

So I concentrated my focus in the gas pedal area and found the throttle cable laying firmly against the oil filler neck. I used a zip tie to hold the throttle cable away from the filler neck and PRESTO, the vibration is gone.

Thanks for help and suggestions

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