Hey guys, in the past week I have started to notice a problem beginning and progressing in my truck's driveline but I can't pinpoint it and I need to ASAP to prevent further damage. What will happen is when Overdrive is on and the truck is in a low RPM range when I give the truck gas it will cause a bucking feeling, possibly like the transmission slipping but I'm nowhere near an expert being only 18 and this being my 1st vehicle. I'm really scared this is going to be a costly repair and I'm close to broke, so if any of you know what this could be please let me know!

Thanks in advance!

 

When you are going down the expressway and your truck is in overdrive does it make a really hard downshift out of overdrive when you step on it?

 

What engine and what year is your truck? Does it do anything else strange like hard shifts or is it just the bucking at low rpms? Also does the bucking only occur when you press the gas?


Sounds to me like a C.O.P or Coil On Plug. They are notorious for going bad, and are most noticeable at low rpms, and especially when going up hill. They also don't immediately set a check engine light. I've had two go bad myself so far and it took over a week for the first one to set off the light.

 

Mine does....

 

It only does semi-hard shifts 2nd to 3rd it seems and it does downshift when I stomp it at interstate speed but not hard. It is just somewhat of a bucking seemingly around the time it goes to downshift when I stomp it, or even when it doesn't downshift. It's a 2002 with a 4.6L auto trans, 2wd with the 4R70W.

 

It sounds to me just like a C.O.P. Especially since its just before the shift out of overdrive, thats when the motor is under the most load and a misfire is most evident.

The next time (or couple times) it does it, don't throttle out, or let off the gas, just allow it to continue doing it, and eventually you'll get the check engine light telling you which coil it is. Also, it may not show a check engine light until shortly after you turn it off and then restart. Mine always waited for the "misfire within first 1000 revolutions" code, to show the check engine light.

Good luck and let us know what happens!

 

Just an update, I took it to the trans shop Friday and they pulled the pan Monday and saw shavings so it's getting rebuilt at the moment :\.. I've been without my truck for 4 days ((

 

that sux man, i went thru the same thing with my explorer i had. but my truck did a similiar thing, whenever the engine was under load it woud feel like its bucking and it turned out to be a couple bad C.O.P.s. hope you find your problem and good luck

 

Thanks. Today my brother called cause he knows the shop owner, and the guy said it overheated and fused a bunch of parts together so it needed a full rebuild.. Ugh I've been without it for 5 days now. And it's undoubtedly gonna be at least a full week :\\