SJ410 rear diff housing....again

[Wooky]

HI All,

My SJ410 has cracked the spring perch weld on the rear diff again. This is the 2nd diff housing it has done it to and in the same place both times.
I think it is a factor of both the age of the diff housings (fatigue) and the amount of flex I have in the SJ suspension over torquing the thin side tubes.

Does anyone know of someone who can make up a new diff housing (upgraded and strengthened) for me?
Preferably in Gauteng but at this point anywhere in SA will be good.

The obvious solution would be to swap in Toyota diffs but I am reluctant to go that route as it would require swapping both the diffs to match.
I have two good diff center portions with lockers installed and swapping in the Toyota diffs would require starting again with the lockers which is going to be costly.
Possibly the cheaper option would be to have a new diff housing made up.... so want to explore that first.

Thanks

W

[jakeslouw]

I'm a little confused: the SJ410 is Spring Under Axle?
How do you get so much movement in your axle tubes to break the spring perch? That would imply loose U-bolts as well as some insane torsional forces.

Pics would help.

Anyhoo....

What I've seen is that on thin axle tubes like the SJ, some guys take thick wall tube with an inside diameter roughly similar to the outside diam of the SJ axle tube, spilt the thick wall tube in half length wise, and weld that OVER the SJ tube as a sleeve.

I think it would be easier, cheaper and faster to swop out for Hilux axles but I understand the locker investment.

And then completely left field: Maybe a 3- or 4-link suspension conversion if you're pushing those leaves to those extremes.

[Wooky]

Hi Jakes,

Yep, the SJ is still spring under but I have quite a bit of travel with the set up I have.
Combine that with narrow axles and I think I am over torquing the thin walled tubes.....pic attached is not quite full stretch

The u bolts are tight. Torqued to 100Nm as per the manual....Could these be tighter?

Would love to go with a linked stetup but just fitted new OME leaf springs the end of last year.
Also why I am keen to stay with the setup I have.
Have quite a bit invested in it so far and it works well if I can just stop cracking the spring perches

Will attempt to brace the diff if I can't find anyone to make a new / upgraded one.
My only worry with that is keeping the axel straight while doing a backyard job on it

[jakeslouw]

I haven't heard of any company in ZA that can competently build axles outside of maybe Gearmax and they will charge more than the value of the Suzuki.......

I'd consider a set of Dana axles from a rusted out XJ Cherokee..........at least they will be cheap and you'll be able to find many upgrades for them.

[Wooky]

I have been looking around for the past month and have come up short on anyone who would be able to do it.
Gearmax didn't even respond to my enquiry.

A new housing would be option 1
Option 2 is to try and beef up the housing I have
Option 3 will be an axle swap

[jakeslouw]

Well I reckon you can throw Option 1 out the window.
Even Option 2 would be a challenge unless Grips can provide info on suitable fabricators.

I suggest you become firm friends with a local engineering shop.

[Asjas]

Wooky. the best way to mod the std axle imo will be to grind the brackets off completely and install a wider and deeper sitting perch like the ones from Rocky offroad.

Going full coil over has plenty of issues on its own, and like you said, everything is basically new. why change everything for one failing part.
As for welding on the diff housing, its not as bad if you alternate your weld and stick to roughly 15mm beads at a time.

[Wooky]

Thanks for the input guys.

Will give option 2 a go and see what happens.
Asjas....Good point about the depth of the stock spring perches, Will look at that.

Anyone have a simple method of checking the straightness of a diff housing?

[jakeslouw]

Anyone have a simple method of checking the straightness of a diff housing?

Ideally you need to strip it down and use a laser, but I've seen guys use thick wall DOM tubing, with a slightly smaller diam than the axle tubes, pushed all the way through and then measure the clearance at several points between the axle tube and the DOM tube at the pumpkin.

Here is another way:

https://www.youtube.com/watch?v=ilx6TOXIN1w

[Wooky]

Thanks jakes..... will give that a go

[grips]

Anyone have a simple method of checking the straightness of a diff housing?

Run it between the centers of a lathe.

Very easy to a tube replacement on a diff. Drill out the welds on the center casting. Knock out the old tubes.
Cut off the bearing flanges on the tubes.

Have thick walled tubes made by an engineering shop. Press the tubes and flanges back in. Put in a lathe and line up. Do the welding while in the lathe to make sure the housing stays true.

[jakeslouw]

Grips, to put a whole axle in a lathe implies a bloody big lathe.............

[Asjas]

Anyone have a simple method of checking the straightness of a diff housing?

Run it between the centers of a lathe.

Very easy to a tube replacement on a diff. Drill out the welds on the center casting. Knock out the old tubes.
Cut off the bearing flanges on the tubes.

Have thick walled tubes made by an engineering shop. Press the tubes and flanges back in. Put in a lathe and line up. Do the welding while in the lathe to make sure the housing stays true.

Will work but might cost a fortune. most Americans with Chrome molys and 35s just weld a full axle gusset on which keeps axle straight and beefs it up considerably.

[Wooky]

Thanks for the input guys....

Checked the original diff housing (1st one to crack the perch weld) and see it is quite bent.
Will strip out the diff from the SJ next weekend and get to work on it.

Plan of action is to pull the spring perch off and repair the crack.
Then brace the diff in such a way as to link the brace with the spring perch.
Then bash on it and see what happens

If that fails I am thinking of modding some jimny gen 3 diffs to fit in a spring under configuration