Hard slam when accelerating?

when i am driving down the road and i let off the throttle and coast, then resume onto the throttle there is a hard slam coming from either the rear end or something along the drivetrain. anybody experienced this, tried searching but no luck, any help would be greatly appreciated. thanks

 

Maybe axle wrap?

 

I notice something similar if leave the shifter in "2" (say, when crawling through a traffic jam). If I leave it in "3" or higher, it doesn't exhibit this symptom.

 

Automatic or manual?

 

slip yoke needs grease maybe

 

I had this issue going from 0-20 took it to the dealer and they reflashed the ECM, they had to recalibrate something it was in a TSB.

 

If your truck has been to the dealer for the brake override recall, it already has the latest ECM software with all the shift logic fixes in it.

 

^ You thinking low transmission fluid in the automatic tranny?

 

automatic

 

trans mount or engine mount?

 

Fuel slosh in the tank. It sounds like the rear cab wall caving in whenever I put my foot into the brake. 4 cyl too slow to have it happen when accelerating.

 

sounds like a bad torque converter.

 

I had something similar happen to me on Friday on on my way to work. Mine felt more like a tranny slip though. I was on the gas cruising along, let off the throttle to slow down to get off the highway. Then when i slowly got back on the gas the tranny had a hard time hooking up, felt like a major slip.

 

hey, where teh boobs go?

 

My 09 did that. I asked my wife WTF was that? It felt like my truck downshifted on me. My 2012 has yet to do it though so hopefully everything is ok.

 

bad piston return spring...

 

Curious as to the logic on this one. How would a bad return spring cause a harsh shift (assuming it IS a hard shift, and not something else)

 

A lot of the transmissions do this. My 2004 Matrix did it. You get used to it.

When you are cruising along and let off the gas and coast for a bit then hit the gas again it seems like it slaps back into gear. The harder you jam on the gas the harder the slap.

I think it is designed that way for gas conservation, like the opposite of torque converter lock up at speed. Let off the gas and it goes into a coasting mode, jam on the gas peddle again and it jams it back into gear.

That said I drove my Matrix for 8 years with no problems.... I have noticed my 2012 does it just a little, but hardly noticeably at all. Meh, no big deal.

 

i was just joking haha no such thing as a piston return spring.. its like blinker fluid or a muffler bearing

 

Axle wrap?