Computer geek/IT Student
Join Date: Jul 2010
Location: Upstate NY
ComputernerdBD is offline
Pop or bang from underneath truck when put into gear
Hey everyone. This totally confuses me in several ways, so here it goes. It is around 10F here in upstate NY with 40mph winds. When I put my car into reverse after moving forward and sometimes into drive after moving backwards, I hear a pop or soft bang coming from under the car. I can hear it if the window is open and yes, I do feel it going into gear. The car seems to be driving normally with no other sounds. This has been happening over the past couple days, especially when it is cold. I just had the transmission fluid changed with a deep pan installed plus a 1/2 qt of Lucas put in (full quart was used last fluid flush). I also had a transmission cooler installed last year. Just recently, I also had to have the rear diff pinion seal replaced and I just changed the fluids in both diffs and the transfer case (and there are no leaks). A few months ago I changed the throttle position sensor and it improved shifts a bit.
The real confusing part is that after driving it around for 10-15 minutes, I tried shifting it again between R-pause in N-D and back and it was 90% quieter but with the same jolt going into gear. What could this be?
1998 GMC Jimmy 4.3L/4L60E/NP233 SLT
Mods: Fog Lights, eBay Eurotails, Spectre Cold Air Intake, B&M transmission cooler, deep trans pan, interior LEDs, Posi-Lok