2000 Gmc savana van 1500. It occasionally will shift hard from first to second gear usually only when its hot or in a traffic jam. This then triggers the service engine
light. The shift hard is hardly noticeable but it has prevented me from getting the van Echecked. Most of the time it shifts smooth with out any problems, Is it an over sensitive sensor or is it a shift module. the check engine light will go out for days but it never fails every time i take it to get it e checked the light comes back on with code p1870
JA: Do you have the trouble code? Do you have a code reader or scan tool?
Customer: had it read by a mechanic .p1870
JA: Are you hoping to fix this yourself?
JA: Great! What have you tried so far?
Customer: I had some other issues with the van shutting down when hot. I replaced the crank position sensor. I also had a blown intake manifold gasket that was leaking anti freeze. Boy was that a job on the van. I tunes up the van hoping that if it ran better it would shift better,I also put an additive in the trans fluid. Lucus, like I said it is hardly noticeable. it never slips out of gear. if im stuck in a traffic jam it will shift a bit hard in and out between 1st and 2nd gear depending on my speed in a traffic jam 0 to 25 miles an hr
JA: Is there anything else important you think the Chevy Mechanic should know about your Chevy?
Customer: 220,000 miles on it on original engine and transmission. I also replaced the radiator
. In the winter the symptoms go away
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and then connect you two.