Strange Transmission Behavior

[esckjc]

My '08 AWD has about 42k miles. Recently I pulled into the driveway after a freeway run of about 40 minutes @ 75MPH. The temperature was in the 60's. Thirty minutes later, I started the car and backed up. The car felt like the brakes were still on (they weren't). The engine was straining, but the car wasn't moving easily. Once in the street, I put it into drive with the same results, engine working hard but not moving very fast. I went slowly around the block with no change and no shifts occurring. There were also no warning lights showing a problem. Back in front of the house, I shifted into reverse and was treated to a loud bang (or wham). I put it back into drive and parked it for about 15 minutes. Before I shut it off, I checked the fluid, it was full, clean and smelled normal. After 15 minutes, I started the car. It was fine and has been so for the last 3 days. Any ideas?

[TnDEdge]

Brother is senior maaster tech at a dealership in CO I will link this to him in an Email and see if he can paint any pictures with this information.

[esckjc]

Brother is senior maaster tech at a dealership in CO I will link this to him in an Email and see if he can paint any pictures with this information.

 

Excellent, and thank you. I dropped off the car at the dealer today. I'm not optimistic.

[CorporateEdge]

Do you using the parking brake ?

 

Were you able to "locate" the sound of the bang? (was it in front/middle/rear of the car?).

 

I still think the parking brake does not release fully based on the "feel" I get occassionally from my 08. Seems like something is holding it back. And before anyone comments, no there are no warning lights and yes the pedal is fully up/released. Supposedly the tranny "learns" how you drive and adjusts shift patterns to match it somewhat. I get a sudden hard shift when starting off on cold mornings, usually going from first to second. As I don't go screaming up the street (live by a school zone) I think the tranny does its own thing every now and then just for the fun of it.

 

Hopefully someone will help you out.

[esckjc]

Do you using the parking brake ?

 

Were you able to "locate" the sound of the bang? (was it in front/middle/rear of the car?).

 

I still think the parking brake does not release fully based on the "feel" I get occassionally from my 08. Seems like something is holding it back. And before anyone comments, no there are no warning lights and yes the pedal is fully up/released. Supposedly the tranny "learns" how you drive and adjusts shift patterns to match it somewhat. I get a sudden hard shift when starting off on cold mornings, usually going from first to second. As I don't go screaming up the street (live by a school zone) I think the tranny does its own thing every now and then just for the fun of it.

 

Hopefully someone will help you out.

The dealer found nothing, of course. I thought about the parking brake so I tried moving with it engaged. Immediately the warning lights came on. That still doesn't mean that the brake wasn't engaged even though the brake pedal had relesaed. Sounds unlikely, but still the best suggestion so far. Thank you.

[akirby]

The dealer found nothing, of course. I thought about the parking brake so I tried moving with it engaged. Immediately the warning lights came on. That still doesn't mean that the brake wasn't engaged even though the brake pedal had relesaed. Sounds unlikely, but still the best suggestion so far. Thank you.

 

Should be easy enough to test. Next time it happens, jack up and test each rear wheel and see if it turns freely. If not then the brake is stuck.

 

And just FYI - these transmissions don't learn your shift habits. It only learns how your transmission responds to each shift request and it constantly adjusts the shift pressures to maintain optimal shift times. How you drive doesn't matter except that it determines which shifts (from/to gear, rpm and throttle) get learned and which don't.