I thought I would provide some information about getting long term service from the 4L30E automatic transmission that is installed inmy 2001 LS2WD Trooper. I've learned through research that you do need to change the automatic transmission fluid at least every 25K miles, even in normal service conditions, regardless of what the owner and shop manuals say. The procedure torefill the fluid includes pumping in the new fluid through the bottom fill plug, which is separate from the drain plug, until fluid starts torun out. Then start the engine with the transmission in neutral and add fluid again until it just starts to run out again. Install the fill plug while the engine is still running with the transmission in neutral while the torque converter is still full of fluid. Don't remove the fill plug with the engine stopped. A lot of fluid will run out that is normally in the torque converter while running.


Regarding the mode switch on the driver side of the transmission, remove the switch, open it up after removing the star screws and clean thoroughly with electrical contact cleaner. While the switch cover is still open, plug the vent tube hole in the switch body. That's where most of the water comes from that causes the switch contacts to corrode and the transmission controller to misoperate. The symptoms for this problem are random gear position in the instrument cluster and hard down shifting, plus occassional sticking in the same gear and not shifting

 

Great Info! My 97 trooper has the same transmission. Yesterday it started staying in gear longer and shifting really hard. I unhooked the battery to reset the computer and it seems to have corrected the problem.


But bet the real problem is the mode switch.


I have been looking for some info on servicing this transmission. What do you use to fillit with fluid? Was a filter and gasket kit easy to find?


There is a cross member on the back of the transmission I assume you have to support the transmission and remove that cross member to get Pan off since the cross member covers part of the pan?





Thanks for the info!

 

I haven't replaced the filter yet. I used a hand pump to pump the ATF through a piece of tubing that I made into a J-hook shape to hang on the inside of the fill hole - it takes some patience, especially during the second part of the filling while the engine is running.

 

What kind of hand pump? Is it something they have at the auto parts store?

 

It's a plunger type that I got at ACE hardware that is rated for petrochemical liquids

 

Is the 4L30E a GM transmission?

 

Yup, the 4L30E is a GM transmission. GM used to or perhaps still does own 51% of Isuzu. I believethe 4L30E is also used on some years of the BMW 3 series cars. It's an OK transmission, but you have to change the transmission fluid on regular intervals, regardless of what the Isuzu owner/shop manuals say.

 

im not sure, but is that only isuzu america... i belive that early isuzu models are all isuzu but im not sure...