We currently own a 2002 LS Trooper (43K miles). We bought it new and have had zero problems with it. I've been trying to stay on top of all necessary service items.

Just took it in to an Isuzu dealer to have the tranny flushed and refilled. They also lubed the telescoping drive saft (grease fittings -- didn't know they were there??). It's been a couple of weeks now....and I've notice something that I've haven't noticed before. When the Trooper shifts into OD, the vehicle shudders (i.e., small vibrations). It doesn't happen every time, just when the RPMs are low. For example, if I take away quickly from a stop and keep up the revs, the vehicle shifts smoothly, as expected. However, if I take away easy and keep the RPMs lower (I would consider this "normal" driving), the vehicle will occassionally shudder once it goes into overdrive. It doesn't do it all the time, but it does it enough to cause concern.

I took it back to the dealer and they test drove it and checked all the codes. Everything came back normal. One of the main reasons I bought the Trooper was for the outstanding warranty. However, I would rather not have to use it to replace the tranny, etc. Has anyone else noticed their Trooper shudders when going into OD. If so, what did you do to fix the problem?

First I would check for proper ATF level. Check amigo-2K's FAQ's for that, or seach this or the rodeo forums for '4L30E' or 'ATF level' A bad intake manifold gasket has also been known to cause RPM fluctuations just large enough to randomly lock/unlock the torque converter at odd times. Make sure you and your dealer document the heck out of this for your protection! I wouldn't sweat it as the 4L30E will last a long time if you keep good clean ATF in it & address any issues right away.
G/luck
Joel

First I would check for proper ATF level. Check amigo-2K's FAQ's for that, or seach this or the rodeo forums for '4L30E' or 'ATF level' A bad intake manifold gasket has also been known to cause RPM fluctuations just large enough to randomly lock/unlock the torque converter at odd times. Make sure you and your dealer document the heck out of this for your protection! I wouldn't sweat it as the 4L30E will last a long time if you keep good clean ATF in it & address any issues right away.
G/luck
Joel

The dealer has double checked the tranny and stated that everything looked good.

So now I'm focusing on the IMG.

Went to Autozone yesterday and they pulled the codes...nothing.

Does a bad gasket trigger a code?

sometimes there will be a code and sometimes not. Usually it is a misfire code.

Have you ever ran a bottle of Injector cleaner (Techron Concentrate)?

You could have the Intake manifold gasket leaked check.

Be happy you have a 10yr 120 warranty! all of them gaskets are covered!

.....Be happy you have a 10yr 120 warranty!

No doubt about it. Keep on the dealer in regards to this issue. I know it's a pain, but try another dealer if you have to!

G/luck
Joel

Did you change the filter? Mine did the same thing - 40mph, light throttle, shudder - I changed the filter, put synthetic fluid in it, added a cooler - problem went away. Good luck.

Did you change the filter? Mine did the same thing - 40mph, light throttle, shudder - I changed the filter, put synthetic fluid in it, added a cooler - problem went away. Good luck.

Made an appt. to see the dealear. The vibration/shudder is still present.

I took it in a few weeks ago and they checked the codes and verifyied the Tranny fluid level. Everything checked out OK.

When I called them back to make the new appt. I told them that I had done some research and found that it might be the IMG. They said to bring it in and they would check it out.

I also asked if they replaced the filter when I had the Tranny flushed and he said there is no filter on the Trooper's. Just a screen?

Does this sound right? I was under the impression that the Tranny had a filter?

Yes it has a filter - it is kinda a pain to replace - but it does. Just did it on my 01 and will soon do it on my Fathers 02