my truck started slipping on the interstate today. the tc locked up a few times and it seemed to run right, but the rest of the time it was slipping pretty bad. i thought it was tranny or converter trouble, but when i stopped to check my fluid, the motor was shaking a lot more than usual. i don't have a service light on. could a motor problem cause the transmission not to lock up?

 

a misfire will cause the converter to not lockup or lock and unlock. I'd start be checking your plugs and wires or just replace them if it's been a while...

 

i'll check that, but won't a misfire throw a code?