Mechanics

TRUCK "JERKS" AT INTERSTATE SPEEDS AFTER 40 OR 50 MILES.

2003 GMC Sonoma • 145,000 miles

2003 GMC Sonoma 4x4 145,000 miles. The truck has recently developed a "jerk" when driving down the interstate. It is a hard enough jerk that you can feel it in the rear end of the truck (differential gears jerking). It only happens when driving at interstate speed for about 40 or 50 miles. Once it starts, it happens regularly about every 30 seconds or so. You have to pull over wait a minute or two and you can drive another 40 or 50 miles before it starts again. Over the last week or so it is getting more frequent (happening at a shorter distance 30 miles or so). I have checked the transmission fluid and it appeared ok. I have changed the differential fluid and I did not see any metal shavings in the old oil. The gears appeared to be ok (no obvious damage to any of the teeth). The driveshaft feels tight when I grab it and try to move it. I am not sure where to go from here. I initially thought it was in the drivetrain, but now I wonder if there is something electrical that is getting hot (but only at interstate speeds seems to eliminate that). Please help.
Avatar
Kiffin1
July 5, 2012.




The TCC solenoid may be kicking in and out. You will have to get a tech to drive it to verify that.

Wrenchtech
Jul 5, 2012.
Are there any tests I can do to confirm that is it or narrow it down in any way? Thanks.

Tiny
Kiffin1
Jul 5, 2012.
Drive it in 3rd gear and see if it stops.

Wrenchtech
Jul 5, 2012.
Thanks for help so far. I will try to recreate the problem over the weekend and follow-up with you.

Tiny
Kiffin1
Jul 6, 2012.
Believe it or not it took this long to recreate the issue. Friday evening it began to do the same thing I described above. I shifted down to 3rd gear and it continued to do the same thing. I noticed it did not "jerk" when I coasted (foot totally off the gas). I pulled over and it drove down some side roads and it eventually stopped (after about 5 miles). After that it seemed to drive fine.
AD

Tiny
Kiffin1
Jul 23, 2012.
Sounds like the engine is just misfiring. Check it for tune up.

Wrenchtech
Jul 23, 2012.

AD