Bolt head in rear diff..

[Summiitt]

Hi, found this in my rear diff today, 2012 130 ute.. carrier bolt head by the looks?
Diff hasn’t been making any noise or any issues, what’s the best replacement option?

[JDNSW]

I'm thinking it is the head off a bolt holding the crown wheel. If it has broken off, what are the others like? As a first step consider jacking up a rear wheel (chock front), handbrake off, remove the level plug and see what you can see as you rotate the diff. If it is a salisbury, remove the rear cover to have a look. If it is a Rover diff, you can fairly easily remove it by pulling both axles, disconnect prop shaft and drain it.

With either diff type, you need to be certain where it came from. If you are lucky, it is a leftover from a previous repair and no further work will be needed. If it is one of the bolts holding the crown wheel on, replace all of them with new ones, correctly torqued (ff a head has broken off, were they overtightened? or faulty bolts?). I am not sure, but you may be able to do this (one at a time) without further disassembly. If it is quiet, and this is the only repair needed, then you should not need to make any adjustments.

[DazzaTD5]

Yes as noted its a crown wheel retaining bolt (well the head anyway). The P38 diff if you work them, towing, offroad can break them. When you pull the diff out you will likely find bolts next to it broken and bolts on the opposite side of the crown wheel broken.

Good time for a rebuild, while it may not be noisy yet I would say there will be plenty of backlash in it.

[Summiitt]

Thanks, Ill pull the diff out in the morning, definitely crown wheel bolts. its at 200,000k of hard off road and towing, so I think I will go an Ashcroft conversion, but will renew all CW bolts in the mean time.
Are there any Ashcroft diffs available in the country or are they an order in from OS?

[DazzaTD5]

Thanks, Ill pull the diff out in the morning, definitely crown wheel bolts. its at 200,000k of hard off road and towing, so I think I will go an Ashcroft conversion, but will renew all CW bolts in the mean time.
Are there any Ashcroft diffs available in the country or are they an order in from OS?

*Direct from Ashcroft it wont take long to get here, the new ATB for the P38 doesnt need the spacer ring fitted.
*Replace the bearings while you are there.
*Also if as you say hard offroad and towing, its likely going to need a new crown wheel and pinion.
*Once carrier is removed, check the bite pattern and amount of wear on the teeth.

[Killer]

G'day Summitt,
If your crown wheel bolts were like the ones on my front diff, (2002 Td5 130) they have serrations under the head face, the serrations dig into the cast iron carrier over time, and allow the bolts to loosen. I replaced mine with ARP bolts, with a smooth face, after needing to replace my crown wheel and pinion after it chewed though a few bolt heads. In my opinion using serrated head bolts against cast iron was a very poor design.
arp-bolts.com

Cheers,
Mick.

[Summiitt]

Well, every bolt had sheared off, and amazingly none had gone through the CW/P. Given the vehicle is off road nearly everyday, everything is in perfect condition.
Ive put it all back together with new HT bolts and will look into a new locker and fresh bearings etc.
Its incredible that the vehicle showed no signs that anything was wrong with the diff, zero noise or backlash, probably got it just in time before it exploded all together!

[Phil B]

Wow!
Buy a lotto ticket!!

[JDNSW]

Were the bolts sheared (failed between C/W & carrier) or the heads detached? Which would most likely be due to overtensionedor faulty bolts.

[Vogler]

The bolts are often not loctited from factory, although the overhaul manuals mention that it should be done.
My front diff ate a couple of bolts last year, I could remove most remaining crown wheel bolts by hand. It probably isn't a coincidence that this happened a couple of weeks after a trip with lots of corrugated roads.
I used allen bolts with nordlock washers and loctite 270. I didn't reuse the diff housing (installed an ATB instead), but my indie told me to have the serrations milled flush in case I wanted to do so.

Joris

[mfc]

Thanks, Ill pull the diff out in the morning, definitely crown wheel bolts. its at 200,000k of hard off road and towing, so I think I will go an Ashcroft conversion, but will renew all CW bolts in the mean time.
Are there any Ashcroft diffs available in the country or are they an order in from OS?
I got my Ashcroft here... was ordered and not picked up.... they used to be fast as, however call and do a Covid delivery check... if there stocked inau there Likly to be heaps dearer... as s as an example a rear Detroit for a sals I’d be looking at a 30% markup aus sorced versus import from USA and installation cost here ... that’s close to trar maxidrivrs n flanges

[p38arover]

Thanks, Ill pull the diff out in the morning, definitely crown wheel bolts. its at 200,000k of hard off road and towing, so I think I will go an Ashcroft conversion, but will renew all CW bolts in the mean time.
Are there any Ashcroft diffs available in the country or are they an order in from OS?

I thought I saw an Ashcroft locker box on the shelves at KLR Auto last week.
Re CW & P, I have a couple of spare pairs I bought after breaking my P38A rear diff. Having spares in the garage meant I’d never need ‘em. :D

[p38arover]

I had to go to KLR Automotive today and I checked. Yes, they have Ashcroft lockers on the shelf. Two different styles, ASHATB and an air locker.

[4bee]

I thought I saw an Ashcroft locker box on the shelves at KLR Auto last week.
Re CW & P, I have a couple of spare pairs I bought after breaking my P38A rear diff. Having spares in the garage meant I’d never need ‘em. :D


Yeah Ron, that seems to be a rare phenomenon. [bigrolf]

My young bro bought one of those standby battery starter things. When I asked if he'd given it a Test Try he reckoned that now he's got it it's a guarantee that he'll never have a flat battery ever again, so he wasn't going tp push his luck beforehand. He is confident it will work one day.

But he drives a J**P thing so what would he know?[biggrin]

[Toxic_Avenger]

:ttiwwp:

@summitt - make it so.

[ian4002000]

i put Loctite onto the crown wheel as well as the bolts after mine sheared all the bolts off.
The original bolts are very high tensile so reorder genuine if fitting original diff. centre

Ian
Bittern

[Summiitt]

Were the bolts sheared (failed between C/W & carrier) or the heads detached? Which would most likely be due to overtensionedor faulty bolts.
The heads had sheared off, all of the threads were still in the CW/P

[Tote]

Was it clunking between forward and reverse? I had an E locker fitted in mine a few weeks ago and after the replacement it no longer has a clunk from the diff that had developed over the last 20,000K or so. I didn't do anything about it as I knew I was getting a locker, but the fitter said that they didn't notice anything untoward when they disassembled it.
Oddly enough my diff has the Disco 1 style axles with the drive flange on the axle and I had exactly the same clunk on my Disco 1 that the dealer rebuilt the diff on under warranty.

Regards,
Tote

[Summiitt]

Was it clunking between forward and reverse? I had an E locker fitted in mine a few weeks ago and after the replacement it no longer has a clunk from the diff that had developed over the last 20,000K or so. I didn't do anything about it as I knew I was getting a locker, but the fitter said that they didn't notice anything untoward when they disassembled it.
Oddly enough my diff has the Disco 1 style axles with the drive flange on the axle and I had exactly the same clunk on my Disco 1 that the dealer rebuilt the diff on under warranty.

Regards,
Tote

Hi Mate,
Yes it was clucking backwards and forwards, about 40,000km ago!! I thought it was rear control arms, so replaced, and it gradually disappeared..cant believe it held on for so long and didn't destroy anything, given what it does for a living.. now its got all its bolts in, I can't believe how much play was in it!!
Hows your Elocker? I'm looking at the Harrop as my bearings will need replacing given the metal in the oil, thought I might as well do the lot..who fitted it?

[Tote]

Hi Mate,
Yes it was clucking backwards and forwards, about 40,000km ago!! I thought it was rear control arms, so replaced, and it gradually disappeared..cant believe it held on for so long and didn't destroy anything, given what it does for a living.. now its got all its bolts in, I can't believe how much play was in it!!
Hows your Elocker? I'm looking at the Harrop as my bearings will need replacing given the metal in the oil, thought I might as well do the lot..who fitted it?

I found out that the E locker is useless on red clay in the Brindies the other week, mind you after it failed to proceed it slid back about a metre with all the wheels locked. Aside from that I havent had the opportunity to test it but engagement and disengagement work well. I got Johnny from the Series Shop to fit it but I had to book the job in June to get it done early this month....

Regards,
Tote

[fatnold]

G'day Summitt,
If your crown wheel bolts were like the ones on my front diff, (2002 Td5 130) they have serrations under the head face, the serrations dig into the cast iron carrier over time, and allow the bolts to loosen. I replaced mine with ARP bolts, with a smooth face, after needing to replace my crown wheel and pinion after it chewed though a few bolt heads. In my opinion using serrated head bolts against cast iron was a very poor design.
arp-bolts.com

Cheers,
Mick.

did you source your ARP bolts locally???

[Killer]

did you source your ARP bolts locally???

I sourced my ARP bolts from a local engine reconditioner. This is a list of suppliers in Australia, The Official ARP Web Site | Dealer Locator (https://arp-bolts.com/p/dealers.php)
Cheers,
Mick.