Chevy 1500 mechanical ?

[lotoftoys]

I have a 2004 Chevy 1500 4x4 with 65,000 miles on it. It started "bucking" a little at 50-55 MPH when in overdrive. It idles fine, runs fine all the way up, and runs fine again after 60 MPH plus. When it bucks it almost feels like driving over a vibe patch before a toll both only not as violent. If you hold the speed in that range it will vibe for a coulpe seconds, go away and return from time to time. Could it be an O2 sensor,but i doubt it). It is not in the wheels. I would not think it would be plugs or fuel filter. I was thinking maybe a trans shift solenoid but I would think a "service engine" warning would come up. Any ideas?

 

[garageguy]

I would try plug wires, plugs, dist. cap

 

[snoeatr]

Kinda sounds like the vibration of a bad u-joint.

 

[mxz500rider]

Id start with cap, plug wires, fuel filter, etc. Also check egr valve. Mine was sticky, I have a 94 gmc, and it made the truck have a vibration at 40-50 mph.

 

[burmad69]

Sounds like torque converter shudder, Change the fluid and filter and ad a can of Shudder Stop might fix the problem.

 

[lotoftoys]

Trans

It is a trans issue for sure. I will try the fluid and filter. What do you folks think I should use for fluid? Is there one better than the other?

 

[catguy]

Amsoil ATF not cheap, but good.

 

[ezra]

I had a 04 pos z71. tranny had some kind of valve replaced 2 times in 65k dump that mexacan pos before it is 2 late.I will never buy a gm again after the laundry list of issues with that 04.some fr end drive line parts were replaced at around 55k on that one.2 02 sensors replaced around the same time also but that made black clouds of smoke when you gave it gas so prob not your issue.

 

[snoluver1]

Sounds like a lock up clutch issue. Fluid change probably won't help, but its worth a shot. If that doesn't help, you probably need a new converter or a lock up clutch actuator solenoid.

 

[matman]

My bet is the U joints too-I have 05 Avalanche-experienced similar symptoms and my were sqeakin too.
good luck-

 

[rp7x]

engine miss

does not have a cap just change plugs and gas filter, at 55 that isn't turning many rpm,s = low tourqe

 

[lotoftoys]

Its better now.

Changed fluid and filter. Not an easy job with heat shield on one side and cable support on other side. Anyway, runs like a dream now. We will see how long it lasts. Thanks to all for ideas and advice. Thanks to JD also for the site.

 

[snow_monkey]

Changed fluid and filter. Not an easy job with heat shield on one side and cable support on other side. Anyway, runs like a dream now. We will see how long it lasts. Thanks to all for ideas and advice. Thanks to JD also for the site.

If it comes back suspect a coil pack!

 

[fish633]

I had a 04 pos z71. tranny had some kind of valve replaced 2 times in 65k dump that mexacan pos before it is 2 late.I will never buy a gm again after the laundry list of issues with that 04.some fr end drive line parts were replaced at around 55k on that one.2 02 sensors replaced around the same time also but that made black clouds of smoke when you gave it gas so prob not your issue.

x2