I bought my T100 a few months ago and Changed the oil, oil filter, the oil in the transfer case, front differential, and rear differential. Within a week or so I started noticing the truck would vibrate, only when the truck is not moving, and only if the truck is in Drive or Reverse. It does not vibrate in Neutral (sounds like its under the hood), I know when the truck is in Drive or Reverse it Idles lower at a stop than when the truck is in neutral and that is when i hear/feel it. I checked the oil level today and it looked fine.

Any Ideas?

Need more info...

2WD or 4WD? Lifted? What year?

Can you shoot some vid and post it up? <img src="/forums/images/graemlins/wink.gif" alt="" />

Its a 98 and 4wheel drive. I will see if i can shoot some video of it but tonight I noticed when I turned off the lights and radio it went away and when i turned them back on it came back, or when i used the power windows so i think it has to do with the battery or something else not getting enough voltage to the motor

OK, so it's an idle vibration. Has nothing to do with driving. And as things lower the engines idle, the vibration gets more pronounced. Idle in neutral, it's fine. Put it in drive (or reverse), and the idle drops and there is vibration. Turn on the lights, and it vibrates more.

This may well be normal. The engine is not perfectly isolated from you, and as things pull it down, it will get a little rougher. More so on an engine with years of service. You may be reacting to a non-problem.

But, there are some basic things you can check and deal with.

1. Clean the throttle body. A whole lot of idle roughness happens here when it's dirty. A few dollars on a spray can of throttle body cleaner and some paper towels.

2. Check the base idle. I don't remember the steps off the top of my head, but you jumper and make sure the base idle speed is correct. This makes sure the air motor that adjusts idle for different loads can do its job correctly.

3. Check for obvious dumb loose things. From that screwdriver left beside the valve cover to a broken hood support clip. Things that would rattle and vibrate.

4. Check for lose and broken vacuum lines and such. Fix what you find, if you find anything. Don't forget to check the switching valves for the front axle!

5. Check the battery and its connections. If they are bad the alternator has to work extra hard, and this can pull the engine down.

By "vibrate" do you mean in makes rattling noises or can you physically feel the whole truck vibrating?

i can feel it and hear it, its idling too low or something because when i give it a little gas the vibration goes away, Also in Neutral and Park when the truck idles slightly higher there is no vibration. I was told it could be the battery causing the alternator to work to hard and taking power away from the motor

What's the RPMs at idle? Have you hooked up a OBDII diagnostics device/computer to it? Might help a little. <img src="/forums/images/graemlins/smile.gif" alt="" />

Well, that would be very easy to check! Just measure the voltage at the battery and see if it is dropping when the vibration is happening. I doubt that's the problem, but its a very easy one to check and eliminate.

I would suspect it just has something to do with the low idle when its in gear. Maybe a torque converter or transmission problem?

I took the battery to autozone and had it load tested and it failed. So i bought a brand new Interstate MTP-24F battery and man not only did it fix the weak starting problem, the vibration is not nearly as bad. Im not worried about it anymore.

thanks for all the replys