4wd won't engage

help, I have an 02 Taco 4wd. the front hubs won't kick in, the forward shaft turns but that is it. My boy tells me it will engage sometimes but hasn't for me. The dealer told me to change the oil in the front diff. with 75-90 but this didn't do any good. Is the problem in the diff or one of the switches on the transmission (if so how do I check) sjd182

help, I have an 02 Taco 4wd. the front hubs won't kick in, the forward shaft turns but that is it. My boy tells me it will engage sometimes but hasn't for me. The dealer told me to change the oil in the front diff. with 75-90 but this didn't do any good. Is the problem in the diff or one of the switches on the transmission (if so how do I check) sjd182






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I'd say a vacuum line got disconnected. I dont know how the 02's are setup but take off the skid plate a look around. If someone has the manual they may be able to give you the 411.
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redtoy92, thanks for the reply. I traced out the vacuum line from the diff. it dead ends on the firewall with an end on it, I took it off blew it out but no difference. sjd182

The hubs always turn, even in 2wd. If the front drive shaft is spinning then you DO have 4wd. If you turn sharp on a hard surface, you will find out really quickly. If you have the rare manual hubs, then perhaps they were reassembled incorrectly or need a little grease. A little grease, don't pack it up. If they are packed up with grease they wont won't work at all--maybe that is the problem!

The hubs always turn, even in 2wd. If the front drive shaft is spinning then you DO have 4wd. If you turn sharp on a hard surface, you will find out really quickly. If you have the rare manual hubs, then perhaps they were reassembled incorrectly or need a little grease. A little grease, don't pack it up. If they are packed up with grease they wont won't work at all--maybe that is the problem!
03DC3.4TRD4x4 The hubs are automatic, but when everything hooks up the 4wd light on the dash comes on. When I raise the truck in the air the light is not on, the front axel is turning and the front wheels are not. Could my problem be in the auto hubs themselves? Thanks for the reply, sjd182

when you say the front axle is turning, do you mean the drive shaft? Or do you mean the cv shafts going from the differential into the hubs? (on my truck these shafts are lime green--whose big idea that was I don't know!) If the drive shaft turns and the cv shafts (actual axles) don't then somehow your differential is not transferring power-- I have never heard of this happening but I suppose it is possible. post more info when you get a chance.

when you say the front axle is turning, do you mean the drive shaft? Or do you mean the cv shafts going from the differential into the hubs? (on my truck these shafts are lime green--whose big idea that was I don't know!) If the drive shaft turns and the cv shafts (actual axles) don't then somehow your differential is not transferring power-- I have never heard of this happening but I suppose it is possible. post more info when you get a chance.
03DC3.4TRD4x4, my mistake, I said front axel but I meant the forward drive line. It is not transfering power to the cv shafts. The dealer says there are six switches that could be the problem but I don't know how to check. sjd182

I have no idea buddy. you have an electrical problem of some sort. That is why modern techs get the big money. I think you will have to put up the money to get a real diagnosis. On the upside, electrical problems are generally cheaper to fix than mechanical ones--IF they can be isolated.

Thanks, I think that's exactly where i'm headed

FYI, the tech at the dealership did a diagnostic check 47.00, and said it was the 4x4 position switch on the transfer case. I ordered the part and fixed it in 5 minutes, Thanks sjd182