Mechanics

FOUR WHEEL DRIVE WON'T ENGAGE

1993 Toyota 4Runner

Tires and Wheels problem
1993 Toyota 4Runner Four Wheel Drive Manual 170000 miles

When I shift into four wheel drive I can hear a click, but my car does not switch into four wheel drive. Also the light on the dash does not come on. I am not sure if it is controlled by vacuum or by a motor.
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Cevanoff
December 18, 2008.




Hi cevanoff,

Thank you for the donation.

The system uses manual shifts and the gear lever does all the work of shifting into 4L, 4H, N and 2H. The indicator would tell you whether it is in 4W mode.

I would require some info to understand the problem better.

Are you able to shift into each position without any difficulty?

Are both 4H and 4L both not engaging?

Are you able to shift to Neutral?

There are 2 types of transfer case used and would you be able to identify which is equipped for your vehicle? VF1A or RF1A?

KHLow2008
Dec 18, 2008.
I have no difficulty shifting into each position including neutral. Neither 4H and 4L are engaging. How would I identify what type of transfer case I have?
Thank you for getting back to me so quickly.

Tiny
Cevanoff
Dec 18, 2008.
Hi cevanoff,

The identification is on the transfer case assy. The diagnostic procedures are similar so we shall forgo that first.

It is possible the shift fork sleeve lock pin has detached and the sleeve is now stuck in 2H only. The lever might be mving but the shift fork is not, the reason the dash ligh is not showing.

You need to remove the gear shift lever to manually check the shift fork movement.
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KHLow2008
Dec 19, 2008.
Am interested to know if you were/are able to diagnose this issue - my 4Runner developed the exact same issues earlier today. Click under the dashboard when shift into 4-wheel drive, but no engagement. Tomorrow I'll pull the shifter and take a look as well. With a foot of snow I need this to work! : -)

Tiny
Tschmidt
Dec 27, 2008.
I started at the top: Inspected the relay (located above your right leg as you sit in the driver's seat). I pulled the black cover off the relay and then activated it just to make sure it was working, even though I could hear it click (it was).

Blocked the wheels, went under the 4Runner and inspected the shift linkage (had my daughter shift both levers with the car turned off). It all checked out and was tight (no missing pins/clips).

Located the actuator, which is mounted directly to the front differential, inspected two small vacuum hoses that connect the actuator to the metal vacuum lines (they were fine). I had to remove the protective plate on the underside of the vehicle to readily access the vacuum lines (four bolts).

Started the engine and tested the lines at the actuator for vacuum - the pull was almost non-existent. This was the first real clue to the issue. Be sure to have the emergency brake on and someone who wants you to live in the car doing the shifting. Come up under the car from the rear to avoid the spinning fan blade.

Noticed that the metal vacuum lines were connected into the system via rubber vacuum lines that run up the side of the engine. At the top, they connect into one blue and one red electrical vacuum control.

Upon inspection, found the protective casing had been partially melted away. Pulled the old vacuum lines out and found one of them melted shut and the other one melted open. Replaced both lines and everything came back online and the 4-wheel drive works perfectly again. By the way - when you replace the vacuum lines, be sure to note which goes to the red switch and which goes to the blue. Down below, I found a red and blue mark on the metal connecting tube, so it was easy to keep it straight.

So. My advice is start in reverse order from my repair! Weakest link is the rubber vacuum hoses running down to the actuator.

Good luck!

Tiny
Tschmidt
Dec 28, 2008.
Hi tschmidt,

Thank you for the input and is very much appreciated.

Happy New Year.

KHLow2008
Dec 28, 2008.

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