My 1995 80 series 24valve, automatic, front diff studs holding actual diff to front axle housing have started loosening off or shearing. This is the 2nd Landcruiser VX where this has happened and despite rebuilding with new studs, it continues to happen. Nothing else wrong with the diff, axle etc. Any advice? Am tempted to weld the two together!
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front diff housing studs loosening/shearing
- Thread starter prowland
- Start date
Well that's a strange one. There isn't any torque or other real motive force being passed through the housing. It's effectively a cover and support for the moving bits. There is a degree of rotation I guess but not enough movement to be able to shear off studs. I have to ask, are the internals of the diff in good order and free to turn?
I've had a lot of diffs on and off and I've never encountered this. I don't even stud lock the studs in. Getting the diff off is often the hardest part too so to have loose or broken studs is an odd one. You could locktite them in and then use nylock nuts I guess but I fear you're only masking the cause. I wouldn't want to weld it.
I've had a lot of diffs on and off and I've never encountered this. I don't even stud lock the studs in. Getting the diff off is often the hardest part too so to have loose or broken studs is an odd one. You could locktite them in and then use nylock nuts I guess but I fear you're only masking the cause. I wouldn't want to weld it.
thanks Chris. I have used threadlock in the past, to no avail. The studs seem to shear not through rotation but through intermittent tension I think. The diff is in good condition. I rebuilt it approx 50,000km ago but previous to that (150k km ago?) a bit of loosening off occurred that I managed to get on top of. And previously on a manual VX, the same happened. In that case I didnt personally do any of the repairs but a local mechanic did.
My theory is that the axle tube actually flexes causing it to "hinge" at the housing area, thus pulling away from the diff. The studs usually tend to start failing at the top. Could weld a web across the top and/or front of the housing to stiffen it up perhaps.
or just weld the diff on - unlikely to have to rebuild or dismantle again.
I have had the vehicle for 9 years now and mileage is 365000km plus however much they would it back before I got it.
My theory is that the axle tube actually flexes causing it to "hinge" at the housing area, thus pulling away from the diff. The studs usually tend to start failing at the top. Could weld a web across the top and/or front of the housing to stiffen it up perhaps.
or just weld the diff on - unlikely to have to rebuild or dismantle again.
I have had the vehicle for 9 years now and mileage is 365000km plus however much they would it back before I got it.
I see no physical reason why the front axle would tend to flex at a hinge point at the diff, the axle casing is much bigger in that location and thus likely to be stronger. The main forces on the the axle casing are between the hub (upward or lateral force from the road and rocks) and the spring perch (downward force from the chassis/body). The flex point here is the weakest part of the casing (IMO) where the cannonball is welded to the casing skin.
I appreciate that each side connects at the center and there will be a “hinge” effect, but I would think it minimal. AFAIK, the reinforcement of the casing widely used on extreme Offroad trucks and buggies is to protect against rock damage.
As Chris suggests, this one is a bit odd. I’ve never come across this on any vehicle I’ve worked on, front or rear...
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Where abouts on the studs was the shearing ?
I know this isn't helpful, but there's a million 4x4s out there with axles and diff just like that and welding them is not, I'd suggest, commonplace. Something is wrong. Perhaps your prop is out of phase for example and causing an issue where it's putting uneven pressure on the case - just for instance.
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I have seen an 80 axle bent after rough use (abuse), but there had not been any issues with the studs and thus guy drives hard.
Whilst I have not seen this, I would be inclined to use loctite and a calibrated torque wrench.
Do you have any particular mods that might exacerbate the problem, or a particular driving style thats a little viscous?
Hmmm.........having said that I am hardly the vicars wife when off roading.
Only a thought, have you considered putting a couple of extra hardened mating dowels in?
This does not help with why its happening but may be of future use?
Regards
Dave
Whilst I have not seen this, I would be inclined to use loctite and a calibrated torque wrench.
Do you have any particular mods that might exacerbate the problem, or a particular driving style thats a little viscous?
Hmmm.........having said that I am hardly the vicars wife when off roading.
Only a thought, have you considered putting a couple of extra hardened mating dowels in?
This does not help with why its happening but may be of future use?
Regards
Dave
I had an RTA where some idiot hit me at 80 km/h when I was stationary, dead center on my left front wheel, which unknown to me very slightly bent the axle at the weld between the cannonball and the hollow casing...
They can be bent...
But at the diff housing? I can’t accept that easily...
To shear a stud, it’s either been overtightened causing a fracture or its suffered a huge rotational shear force, which is very unlikely as there are plenty of other studs sharing that force, again it doesn’t add up even if there is a fault with the diff (IMO).
And surely, a fault in the diff to cause such a rotational force would surely simply lock up the front wheels or at least be physically evident (or go with a bang) when driving ...
They bend from the diff casing outwards Clive, you can have them reinforced, there are companies that sell gussets...oooer...you weld them in place.
EDIT: Here you go Clive
https://www.google.es/search?q=land...e-mobile&espv=1&ie=UTF-8#imgrc=UPTT4BUjoXo2TM:
Regards
Dave
EDIT: Here you go Clive
https://www.google.es/search?q=land...e-mobile&espv=1&ie=UTF-8#imgrc=UPTT4BUjoXo2TM:
Regards
Dave
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- Mar 1, 2010
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- 5,515
It's either poor fitting and/or poor driving.
Ive bent the front axel on my 80. If you read up on it its a common fault the aussies have alot with there corrugated roads. First sighn is the biff bolts slacking which happened to me and also depending on how bad its bent you can deform the inner hub seal on the longer side which will pull the grease into the axel and vice versa oil out.
I swapped the axel out another one I reinforced.
I did it in Morroco. The funny thing was a few days before we stopped in Allies garage in Zagora, when he was looking over the trucks he said that reinforcing the front axel is a good idea and showed us a load of axles he had in the shop ready to go. So i blame him for tempting fate
I swapped the axel out another one I reinforced.
I did it in Morroco. The funny thing was a few days before we stopped in Allies garage in Zagora, when he was looking over the trucks he said that reinforcing the front axel is a good idea and showed us a load of axles he had in the shop ready to go. So i blame him for tempting fate
Folks, these 80 VXs have been my everyday vehicle for the past 17 years. They are common vehicles out here because of the road conditions. There are no mods apart from replacement springs which, as with all current 80s, raises the height a couple of cms. Cracked axles (usually along the seam) are not uncommon out here. I suspect that the axle is flexing/bending slightly. The studs generally shear flush with the axle housing - the top ones are where it starts. Kingtom - I think I will have to look at reinforcing the axle
Mmm, always ready to learn something.
Like the look of the reinforcing webs and those tabs for the cannonballs...
At least this explains the popping studs...
