1998 Isuzu Trooper



June, 29, 2008 AT 8:32 PM

Transmission problem
1998 Isuzu Trooper 6 cyl Four Wheel Drive Automatic 71000 miles

1998 Isuzu Trooper. 71k miles. 6cylinder. 4wd. Auto trans. We recently moved from California to Maryland and drove the Trooper the 3000 miles loaded with two adults, 2 dogs, 2 cats and bare essencials. We had a trusted family mechanic do a full workover on the Trooper before we headed out and I asked him to take special interest in the auto transmission. He did so and said everything was ok and since the fluid was still clearish-red that he wouldn't recommend a fluid change until after we got to Maryland. Trooper drove superbly during the trip and for two weeks afterwards.

Just the other morning, (temp in the low 80's like it's been for a while) we got in and it shifted real hard from 1st to 2nd, 2nd to 3rd and when we slowed down shifted hard from 3rd to 2nd but normally from 2nd to 1st. The hard shift is like a " jerk" as the engine revs a bit higher than normal (not extremely, but noticeably) and then the transmission shifts. As for downshifting, it seems to wait a bit longer before downshifting than it used to before a " jerk" as it downshifts. Doesn't miss any gears as it shifts though and no weird sounds or movements in steering. No loss of power and the accelerator is just as responsive.

I checked the transmission fluid (no dipstick so I read online on how to check it from below) and the fluid is SLIGHTLY darkish red but still very redish. No smokey smell, no streaks and no metal flakes in the little bit that dripped out on a clean paper towel I held underneath. BTW: I know what smokey transmission fluid smells like as our Ford Explorer trashed it's auto transmission a year ago.

Another strange thing is the gear selector indicator in the dash isn't always correct. For example, sometimes when I move from Park to Drive, it flickers between P and D before settling on D. Sometimes, there is no indicator light denoting a gear when I shift from P to D. Also, when I shift from P to D, the transmission shifts harder than it used to.

Any idea what could be going on? This doesn't seem 100% like a transmission problem, but then again I'm not a mechanic. I've made a $10 donation in the hopes you guys can help us out.


3 Answers



June, 29, 2008 AT 8:39 PM

Did another test drive around the apt complex and the behavior this time is slightly different. Normal shift from 1st to 2nd, hard shift from 2nd to 3rd. Normal downshift from 3rd to 2nd and from 2nd to 1st. Dash gear indicator still doing the same indecisive thing between P and D. Also noticed that L and 2 do not show any lights at all (this may be old behavior as we have never used those gears via the shifter).

BTW: Trooper has seen all the usual PMs (oi, filter, suspension, engine, transmission services, etc). Has never towed anything other than two mountain bikes and never did any REAL offroad. Used it a few times on dirt roads to/from camping sites but nothing serious.



July, 4, 2008 AT 6:14 PM

Every single time I get a trooper with weird shifting problems the problem has always been a bad throttle positioning sensor. They are real inexpensive and are easy to install. Give that a try



July, 6, 2008 AT 2:23 PM

The range mode switch attached to the driver side of the automatic TOR transmission was the culprit. I combed the web and found a few other car repair websites with great information and followed their tips.

The range mode switch actually had some water in it and the dielectric grease was dried out and crusty. I used a can of contact cleaner and an old cotton t-shirt to clean the range mode switch after removing it. I then caked the switch and the electrical contacts inside liberally with new dielectric grease, reassembled and slowly changed gears while the vehicle was parked.

All the gears show up now (including L and 2 that didn't show up as mentioned in a previous post). Took it for a test drive and she shifts like brand new!

Keep the 10$ I donated guys and have a case of Pearl on me!

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