hey guys (please don't hate me cuz i'm new (and a bit mechanically ignorant). i just bought my 97 expy 4x4 last week (and i think she's great! - and so purty) and her A4wd light blinks (4wd hi & lo seem fine).

so i DID do some searching here...

i've checked the dash switch itself - took it out and apart and it was very clean (just a little clean grease to help the ball move)

so i bought a speed sensor from autozone ($45!) and switched it with one on the transfer case. cut the battery for 10 minutes (to clear the error code)...and still no dice (still blinking).

now i've read that there are two speed sensors, one forumer said it was near the first one (but i sure don't see it) another said it was on the rear diff. i did find a plug on top of the rear diff just like the plug going into the transfer case speed sensor, but it plugs into something that doesn't look like the speed sensor i bought. i tried pulling it out to get a better look but it's kinda stuck in there and i don't want to mess things up without a second opinion.

my questions: is there another 'regular looking' speed sensor that i just can't seem to find? is the thing on top of the rear diff just an odd looking speed sensor (and should i pull it out and try to replace that?)?

any help would be greatly appreciated,
alex

 

i think that the one on the rear end only does the abs system, not sure about a4wd trucks though. the one on the tranny/transfer case is what does the shifting.

 

thanks for the input steve - so does anyone know exactly where the other one on the transfer case is? i read it was behind the transfer case motor. but there appears to be no space behind the motor, so....

 

There is one right behind the transfer case shift motor that monitors the front driveline speed. You have to remove the shift motor to access it which only takes a couple minutes.

 

thanks mtitech - i'm assuming the transfer case shift motor is one of the motor looking things on the end of the transfer case....it really doesn't look like there is any space behind what i'm looking at back there, but i'll give it a try...