Hello, I've had my 92 fj80 triple locked 3fe for about 6 months now and the center diff light has always been on and the switch wouldn't engage it nor would switching to low range. It didn't bother me much as I wasn't doing any off-roading, but now I'm getting ready to sell it as I have a good deal on a Tacoma coming up and I don't have the space for it anymore sadly, and I was knocking off all of the weird problems with it.. and while replacing the stereo I found that the diff lock switch was unplugged. I plugged it in and switched it and I started rolling down my driveway. I turned the truck on and tried to drive it and all I heard was a massive grinding sound so I switched it back and turned it off and it started driving fine. I'm gonna poke around when it's dry again but does anyone know what that could be? the sound was definitely coming from the center diff or somewhere near it. I'll update when I get a look under the truck. This was just about the last thing wrong with the truck before I posted it for sale.
Center diff grinding.. (1 Viewer)
- Thread starter Jesseonaboat
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Check your front drive flanges
Agreed with above.
If the CDL switch was disconnected and the light on when you bought it, you've bought a pup.
Someone was covering up an issue with the front drive line. Most likely stripped out splines in drive flanges on the front hubs, and/ or stripped splines on the birfields
You've effectively been driving around in a rear wheel drive vehicle.
If the CDL switch was disconnected and the light on when you bought it, you've bought a pup.
Someone was covering up an issue with the front drive line. Most likely stripped out splines in drive flanges on the front hubs, and/ or stripped splines on the birfields
You've effectively been driving around in a rear wheel drive vehicle.
- Thread starter
- #4
I've checked the drive flanges, and they look good. It sounds like the sound is coming from right below me.
Could be that the LF birfield has been munched. Would give similar symptoms. I would think you would hear it regularly unless the PO removed the junk parts and just threw it back together. That's been known to happen as well.
You're focused on the transfer case grinding, which is the result, not the cause.
If anything in the front driveline is amiss, you essentially have an "open" in the driveline. When you put the truck in gear, all drive will go to that open. Then when you try to lock the center differential, since one end is spinning and the other is stationary, you will grind the gears in the transfer case as the locking collar tries to slide into position.
I would suspect drive flanges/stub axles as they are known issues. You can't "look" at a drive flange and say they "look good". That means nothing. Pop the grease caps off, chock the wheels, unlock the center diff and put the truck in gear. If you can see one of the stub axles rotate, then you need to replace the drive flange and possibly the birfield.
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