I found out the hard way that my four wheel drive had cut out on my(stuck in some mud). The driveshaft turns but it doesn't seem to lock in the front differential. Anybody know of any tests so that i can get my 4wd back?

How are the systems setup, vaccum or electrical?

 

We need some more info.

1. What year/vehicle?

2. Do you have manual hubs or ADD?

If your front end is stock then you be "locked". It is an open differential so you could just be spinning one tire.

If you have ADD, then you may have a vacuum leak. Check the vacuum hoses.

If you have manual hubs and the CV's look good, then you probably have a bad R&P.

 

Sorry 93 4runner, stock. Open differntail so four wheel drive is really two wheel drive. Light doesn't comme on in the dash. I went to go through some mud on trail that wasn't too bad and when i put the truck in four wheel drive the rearend bogged down and got stuck. Front tires didn't spin but the driveshaft turns. To make things worse i had to get pulled out by a jeep.

 

Hmm, doesn't sound right. The light should go on if the driveshaft turns. I believe the 4x4 light sensor is located at the transfer case. So as far as the light is concerned, check to see if the wires have been cut or if the plug on the transfer case has come out.

As for the actual problem.... I'd definately look for vacuum leaks. Check your front ifs inboard axle. On the drivers side will be the ADD clutch fork mechanisim that engages. Look at all the vacuum hoses coming out. If the hoses look good, or you don't have ADD. Then I'd say you might have a toasted R&P. Drain the front diff and check for metal chunks.

 

Checked all vaccum lines at work. All held a vaccum. Next step is to drain the front end then.

 

I've heard of people switching the vacuum lines at the diff and finding that the one that engages the ADD system was plugged up and switching them actuated the fork and engaged the front diff. you might try that before you drain it. You can access the lines at the back of the diff above the steering rack. wait, I'm thinking of my '98, well, maybe this info will help anyway.

J.

 

Could the actuaator be bad? My freinds did this on his jeep. Just wondering.

 

hey I had that same problem a couple weeks ago. The 4wd sensor I'm pretty sure is located on the front of the differential on the ADD fork mechanism. It should be a white plug that runs up into the engine bay. But I had a local drivetrain shop install my new 4.88 gears and some how they reversed the vaccum hoses on the top of the differential and I found that the sensor wires were crimped and cut the wires. Whenever I put it in 4wd the light on the dash would blink and click a couple times and then go off. I fixed the vaccum hoses on the differential and replaced the sensor wire and now the cv axles engage and turn with the front driveshaft when I put it in 4wd. Hope this helps.