When driving the transmission shift slams / bucks for 2nd to 3rd gear at the 20 to 30 miles per hour. The transmission revs and then bang?S into the next gear. This also happens when slowing down and coming to a stop, you can feel it bucking / jolt (as if it was slipping) as I apply the brake. I had reported this to the Volvo dealer several times and they said that nothing came up on the codes or diagnostic equipment. I had the transmission overhauled too in April 2013 and it ran good for about 12 months and that back to same symptoms / issues. I also brought it back again around August/September 2014 time frame to have the software updated and explained the transmission shifting problem and again no fault codes. My concern is that when driving the vehicle it could be a hazard if trying to accelerate quickly or trying to stop quickly and it does not respond as it should and an accident occurs, and a possible fatality could result. I also did speak with Volvo customer services and register a complaint with them. This is not my first Volvo, I have owned Volvo since 1988. Please advise of findings and resolution.

- Broomall, PA, USA