Transmission only drives in first and second gear

LINDA COVINGTON

MEMBER
1996 ISUZU TROOPER
V6
4WD
AUTOMATIC
230,000 MILES

My vehicle has no pressure line for my three or more gears. If I start out in second gear and dog it up to 4000 rpm's and hold it all of a sudden my transmission light will come on but then my truck drives somewhat like normal in second gear. What could be the problem? I am literally burning through transmission fluid driving like this. Now my check engine light has come on showing P1391. Which I believe is my G Sensor. I have been driving like this for some time now and the check engine light is new. Can anyone tell me why my transmission. Is doing this? Could it be my VSS sensor? Also, I have a power and winter drive push button for the transmission deliver-ability. If that is important to know.

6 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,526 POSTS

It does sound like a VSS that is going out.

Here are some diagrams (below) to show you where the sensor is:

Please let us know what happens.

Cheers, Ken

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Wednesday, August 30th, 2017 AT 11:55 AM

LINDA COVINGTON

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14 POSTS

Thank you for responding. I will definitely try that. One more question, will I need to change out my speedometer when I change out the VSS?

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Wednesday, August 30th, 2017 AT 3:15 PM

LINDA COVINGTON

MEMBER
14 POSTS

Two more questions. Lol. Is there a tool I can use to pull that sensor without having to drop the transmission?

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Wednesday, August 30th, 2017 AT 3:17 PM

KEN L

MASTER CERTIFIED MECHANIC
47,526 POSTS

Hi,

You will not need to replace the speedometer when replacing the VSS, to replace the sensor you should be able just to remove the rear cross member and lower the unit with a jack to get top the sensor without removing the transmission.

Please let us know.

Cheers, Ken

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Wednesday, August 30th, 2017 AT 4:42 PM

LINDA COVINGTON

MEMBER
14 POSTS

Hello Ken
I hope things are going well with you. I do apologize for the delay in response. I had some other life matters that came up. I am still in the same predicament when its comes the trooper. I changed out the VSS, Crankshaft Position Sensor, Neutral Safety Switch, and the Solenoid. When I pulled the VSS I can plainly see that the teeth on the gear have begun to CHIP away literally. I did not change out the speed sensors per hub. Could it be the Winter Mode Switch by chance? Or the other sensors? Even if I decide to just get a rebuilt transmission I honestly would like to know what the issue is? Again, thank you so much for your time and knowledge. Hope to hear from yoy soon!