Member Since: 27 Dec 2020
Location: Pocatello
Posts: 42
Sticking Rear Locking Diff Solution
So, I’ve had a recurring “Transmission Fault - Traction Reduced” error message at startup for months now due to my locking rear diff seizing in the open position. It seems the vehicle tests it at startup each time and evaluates whether or not it’s operational.
Since mine was sticking, it threw the error each time it was started. I have noticed for a while it would also struggle to open after coming to a complete stop then making a 90 deg left turn; it would make a rumble until it could unlock fully. At first I thought it was the ABS activating but if the transmission fault message was thrown and the diff lock motor was deactivated it never would rumble on turns. So I knew it was the locker.
If I ever needed my rear locker for off roading I could crawl underneath and smack the motor housing with a hammer a couple of times to break it loose. It would usually work for a few climbs then bind again but could get me through some tough spots if needed. It always came back quickly however.
I’m very frugal and since I bought this rig for only $5000, I’m not going to pay $1000 to get a new factory motor installed. I generally look for the DIY fix first before replacing parts and even then I’m going to do it myself. In my research I figured out that the likely culprit was the bearing and wheel at the far end of the motor which rested inside a bulge in the housing. I heard of someone drilling out someone drilling out somewhere on the housing and spraying lube inside but didn’t know exactly where. So I made an educated guess and decided to test the theory myself.
I crawled under the rear of the vehicle under the rear diff. Above the diff, on the right side is the “bulge” in the housing where the wheel and bearing were located. I wriggled my drill up there and slowly worked it until it broke through, trying to keep any debris from getting shoved inside once the bit broke through. There seems to be enough space that you don’t have to worry too much about drilling into the actual motor bearing. I then got a bottle of lube with a straw and shot a fair amount of lube in there. But not so much it flooded the unit.
Ever since doing this procedure I have struggled to hear a single sign of it binding. I have done one fairly technical off road outing, the majority on off-road mode which seems to make the locker activate more easily. So far there’s still no transmission fault on startup!
My next step, if this didn’t work, was to attempt to remove the black motor housing WITHOUT removing the entire locker motor. It seems the bolts are accessible enough that it can be done. I haven’t had to go that far yet. I also just covered the hole with duct tape as I tested it so I could reapply if necessary. I will soon cover in JB Weld epoxy putty to restore its waterproof state.
Hope this helps someone else out and possibly saves them a few hundred dollars!
1st Nov 2022 6:26 am
discophil36
Member Since: 17 Jul 2014
Location: Renfrewshire
Posts: 142
I wonder if you could tap a thread were you have drilled, and fit a rubber coated bolt or cap. Then you will be able to access it for regular maintenance and would also keep it water /debris tight.
I so hope I Have a locking rear diff on my V8 when I get it on Friday, I forgot to look while viewing it.
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