Rough idle in Drive

I have a Gen 3 with 700 miles on it. Besides the constant head unit resets and howling noise from the rear diff, I have noticed a rough idle when in Drive. If I shift to Park it goes away. Anyone else notice this? I feel it mostly in the seat. I have searched for this on the forum and the only thing I could find is the shudder when slowing down, but this is different.

 

agree...


OP, take it to the dealership and voice your concerns.

 

Save yourself the trip to the dealer. They'll tell you it's normal for the truck.

 

ahahahhhhhhaahaha, it's possible

 

On a serious note, it's probably the otto/atkinson cycling on or off. One of those fancy doohickeys they have on the motor to self-clean injectors. Sounds like a small diesel motor idling. Others have reported it as ticking or knocking. Essentially the RPMs kick down and it seems to run rough at idle but it is designed that way.

 

Yeah, I am afraid they are going to blow it off as "normal". I'll add it to my list of gripes when I bring it in to get the head unit replaced.

 

OP, sorry about your truck, definately get the dif noise checked out. Best of luck with getting your issues resolved.

 

I had some of the same issues. My diff was replaced and I have the rough idle as you describe, they say normal and it prob is.

 

@bulldog did they give you any issues about replacing the rear diff? Do you have a TSB? Just want to be prepared if I have to fight them to fix it.

Thanks

 

https://www.tacomaworld.com/threads/2016-tacoma-dcsb-or-rear-diff-replacement-other-stuff.423712/

That's the TSB they told me, but when I search it I can't find anything, so I'm not sure if they made it up or it's real.

 

Are you sure its not the AC compressor cycling on and off?

 

In my case, yes, I am positive.

 

Tried shutting off AC. Still vibrates. Doesn't do it in park, so might have something to do with tranny. Not sure.

 

The diff noise is "a characteristic of the truck" unfortunately. Anyone with a Tacoma can get it up to ~60mph and feather the throttle and induce the diff howl. I spent 2 hours at the dealership with a service manager driving various models SR5, Sprt, OR, Limited...and they ALL do it. They also ALL have the rumble strip on stopping. Some worse than others. So, when I hear people say they dont have the issues--I find it incredibly hard to believe. I think they either dont notice them or dont care.

They replaced my rear diff and its not any better. It might actually be a little worse. I haven't noticed a rough idle in drive, but I did notice the other day, while in park waiting on the gf to run into a store, that the truck would go from 500-600 RPM to 1200RPM for about 15 seconds then level off again. Rinse and repeat about ever minute or so.

 

My rear diff basically had no fluid in it for 400 miles. It was so loud that it was undeniably loud, similar to my dads old 60's Chevy 3/4 ton that you can't drive over 55 mph. My new one has 1200ish miles on it and it is quiet.

 

Is the idle rough in reverse too?

 

I hear the droning/howl noise from rear diff too when at freeway speeds. If I take foot off the pedal it goes away.

 

Are you sure it is from the rear? I had a rear differential go out on a previous truck and i could turn my head back (ear towards the rear) and really hear it. I have a howl too at highway speed when on the gas, but it doesn't seem to be from the rear. If I turn my head back I can't hear it as well. Seems like it is coming from the front, but sounds can be hard to diagnose.