So I had a lightweight, under drive crank pulley installed a couple weeks ago. Ever since the pulley has been installed, I am noticing a slipping of either the pulley or transmission at low RPMs in first gear. From a dead stop, when I press the gas pedal, the car will rev up to about 2500-3000rpm and then catch gear. No other gears are affected, upshift or downshift... only accelerating into first from a stop. Any suggestions? Belt is tight and transmission fluid is filled.

 

Sounds like the belt slipping

 

The pulley and transmission are not related to each other.

 

^ what they said, get the belt and the tensioner checked out, most effort is made when you accelerate form a stop thus the belt is more likely to slip then if its not on right. Report back with results

 

+1
I thought that the serpentine belt only drove "auxiliary" equipment like the power steering and alternator. The new pully underdrives these non-timed items. I wouldn't think that the belt slipping could not affect the way that the engine and transmission interact with each other. Puzzling? Not doubting the OP about what happened, just puzzled by the apparent relationship of a underdrive pulley and trans slip. Coincidence maybe?

 

I'm currently running a K070795 belt, however the recommended belt is a K070786. The belt will be switched and I will get back to you guys. Hopefully this solves the issue.

 

i'm very confused.

slipping accessory and alternator belts make a squeal

they have nothing to do with your transmission

you can drive your car without your belts and it will drive perfectly normal until the battery runs out of juice. and obviously you would have no power steering or air conditioning either.

if your transmission really is slipping and your automatic, i would suggest you check the ATF level first. If its stick, then you may have a certain clutch and pressure plate issue.

 

How pronounced is the "slippage"? Could be the engine is revving up faster(reason for the pulley) and then hitting lockup on the TC a little different than you are used to. Is the car standing still till 3000 rpm?

 

Sorry for the delayed response, but I got everything working in order again. I changed the belt to the 070786, as recommended and I also noticed the Trans Fluid was actually a bit lower than it should have been so I added trans fluid. I'm guessing it was the trans fluid that was causing my gears to slip? To install the pulleys, the shop had to remove the radiator, so I am guessing the trans fluid drained from the trans line that runs to the radiator since the 2007 model does not have a trans cooler.

 

RIGHT ON THE MONEY, thank you.