Scary lock-up on motorway

Diffs, axles, lockers, transmissions, portals, that kind of thing.
Bermo
Posts: 13
Joined: Thu Dec 21, 2006 12:11 pm
Location: Ireland

Re: Scary lock-up on motorway

Post by Bermo » Mon Feb 26, 2018 6:17 am

Could anyone guide me on how to troubleshoot the front diff lock actuation? Is there a way to manually disengage the front diff lock?

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Jimm391730
United States of America
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Location: Idyllwild, CA

Re: Scary lock-up on motorway

Post by Jimm391730 » Mon Feb 26, 2018 10:07 am

Is there a way to manually disengage the front diff lock?
Remove the locker slave cylinder and manually move the locker mechanism (assuming it is free to move). You should be able to lock it with pressure, a spring should return it to the unlocked position - the slave only activates the "lock" (through a spring, in case the splines are not yet lined up) and when released, a separate spring should push back against the slave as it releases.
Jim M.
712W and 710M

Bermo
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Joined: Thu Dec 21, 2006 12:11 pm
Location: Ireland

Re: Scary lock-up on motorway

Post by Bermo » Mon Feb 26, 2018 11:57 am

Thanks, will give that a go.

Bermo
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Location: Ireland

Re: Scary lock-up on motorway

Post by Bermo » Tue Feb 27, 2018 7:44 am

I removed the slave cylinder that locks the front diff, I could see the springs and everything looked OK as far as I could tell. I remounted it and drove the truck forward and backwards and was able to engage and disengage the front diff. That is, I flipped the lever and I felt the diff lock engage and the light came on. When I returned the lever the light went off and I could feel the diff lock disengage, as in, I could steer again. So, miraculously, everything seems normal, I can drive around OK and can steer as normal. The only odd thing is that when I jacked up the front axle and turned one wheel the other wheel still turns in sync with it as though it was locked. But when driving the wheel are obviously not locked because I can steer easily. Strange?? Tonight I will drain the oil from the diff, look for metal and fill it with new oil.

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Jimm391730
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Re: Scary lock-up on motorway

Post by Jimm391730 » Tue Feb 27, 2018 11:06 am

The only odd thing is that when I jacked up the front axle and turned one wheel the other wheel still turns in sync with it as though it was locked. But when driving the wheel are obviously not locked because I can steer easily. Strange??
I'm sorry to suggest that the bevel gears in the diff may be damaged (or the shaft that they ride on is bent, I've seen that happen with exec I) in that bevel gears have enough drag that with hand pressure they seem "locked" but with engine force and truck weight they turn with more than hand force. Support both ends of the axle, when you look into the drain hole try to see if the bevel gear shaft ends seem to rotate in the same plane (meaning that one end of the shaft does not seem farther forward or backwards from the other end).
Last edited by Jimm391730 on Tue Feb 27, 2018 1:43 pm, edited 1 time in total.
Jim M.
712W and 710M

Bermo
Posts: 13
Joined: Thu Dec 21, 2006 12:11 pm
Location: Ireland

Re: Scary lock-up on motorway

Post by Bermo » Tue Feb 27, 2018 11:33 am

Thanks Jimmy. Would that be a full diff replacement or just part? Looks like I will have to get it to a shop and get the diff taken apart. I'll have a look through the drain hole ss you suggested and see what I can see. I think the oil may have leaked although I never saw any oil on the ground, but as others have said, it can just go into another part of the drive train. There is oil on the exterior of the diff.

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Jimm391730
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Re: Scary lock-up on motorway

Post by Jimm391730 » Tue Feb 27, 2018 1:42 pm

Well, you have to pull the diff out to both evaluate it and replace what is needed. Execution II improved the bevel gears shaft bearing area and improved lubrication, compared to Exec I. As long as no really big metal pieces damaged any other parts (like be getting wedged in between the pinion and ring gears) if this is the issue then you may only need to do the Exec II upgrade; in this case the cost of the parts is much less than the cost of the labor to fix it. While someone is in the diff it is usually a wise investment to replace bearings and seals - again, the cost of the parts is small compared to the labor.
Jim M.
712W and 710M

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Hotzenplotz
Austria
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Re: Scary lock-up on motorway

Post by Hotzenplotz » Wed Feb 28, 2018 1:08 pm

Bermo

As far as I can tell, Dale at Haflingertechnik or Greg at SGB would be the closest ports o call to you.
Cheers
Albert
========================
My Pinz has NEVER been with any army

Bermo
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Joined: Thu Dec 21, 2006 12:11 pm
Location: Ireland

Re: Scary lock-up on motorway

Post by Bermo » Tue May 08, 2018 7:09 am

I drained the oil from the front diff and this is what I found. Very fine steel filings, and some larger pieces of gold coloured filings. Is this normal wear? Only about 1 litre of oil drained out, but at least 2 litres went in on refill. There were black streaks through the old oil, fine iron filings I imagine. The gear oil was 80W90 GL-5.
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