We keep blowing diffs.

[cruiserkid]

Ok, my mate has just bought a new 4wd.
It's a fj45 tray with a 350 chev, 5 speed 35's etc.
He has the vehicle for a few weeks and has now blown 3 diffs.
He drives it reasonable hard, but nothing more than normal.
I am starting to think he may have a bent diff housing.

Can anyone offer any solution?.

Whats a stronger option without going to a GQ diff?.

If it comes to the crunch we will either put a GQ diff in and convert it coil rear or get a 9" cut down with a detroit locker.
But we are trying the easy options first.

Hope someone can help us with our problem.

[bazooked]

please elaborate on blown diffs...................... are u blowing up the centre? snappin axles?.................................

[Ruffy]

A bent diff housing will break axles not diffs.
When you say you keep blowing diffs which part of the diff are you breaking. Is it crown wheel, pinion, side gears, bearings????
Is he wheeling or just using it on the street.. Is he doing burnouts or anything silly? Front, rear or both?

[nottie]

Also is it locked (welded or air or auto)

[Gwagensteve]

You can break anything if you try.

It should be cheap and easy to check for a bent housing - get your wheel alignment checked - any camber or toe on the rear diff will be easy to pick.

Cruiser diffs are pretty strong, I'd be surprised if there was enough if an strength increase with a 9" to make it worthwhile.

A H260 Patrol rear diff will be stronger in the centre and splines, could be another option.

As per Bazooked - what's breaking?

Steve.

[cruiserkid]

Sorry guys should have been a bit clearer.
It is the rear diff the keeps blowing.
Keeps destroying the spider gears.
Two have blown on the main road and the other was yesterday up the bush.
The diffs are open, no lockers etc.
He doesn't do burn outs or anything like that.
We put the diff in on saturday arvo and it blew about 3.00pm yesterday.
He had only done one hill, nothing to crazy.

[mickdundee..]

I'd say the carrier bearing is too loose

[GUEEY]

Had a 350 Chev FJ40 SWB for 9 Years.
Open diffs then Twin air lockers.
Never blew a diff.
I would think something must be wrong to blow 3 !!

Grant.

[dumbdunce]

...we will either put a GQ diff in and convert it coil rear or get a 9" cut down with a detroit locker.
.

throw out your 9" idea, a 9" is no stronger than the toyota diff. the GQ isn't much stronger than the toyota job either. (wait for the patrol boys to start whingeing about that, but it's a fact; the main reason patrols blow them less often is less torque from the patrol motors) if you are busting spider gears, it's probably driving habits - not necessarily too much right boot, but too quick on the clutch/changing hard and fast, or lugging the motor in too high a gear, which is easy to do with a motor that makes good torque. an easy fix is to get your hands on a 4-spider diff (which will probably be an LSD) from a later model cruiser, eg just about any cruiser from 1989 on, and if you can get one from an 80 series, they have a stronger case and bigger carrier bearings too. bolt in, although you may have to drill the flange to suit your tailshaft.

Alternatively, fit a detroit or airlocker to the stock diff.

buy yeah 3 diffs in a short time = driving habits. if you were snapping pinions it would be a suspension problem, blowing crownhweel/pinion gears could be bearing problems, spinder gears *might* be excessive spider/side gear backlash but 3 times?

[Gwagensteve]

throw out your 9" idea, a 9" is no stronger than the toyota diff. the GQ isn't much stronger than the toyota job either.

I figured the H260 would have been a fair bit stronger than the cruiser diff, and as a leaf diff should be easy to fit, but agree with your point especially in relation to the 9"

Steve.

[dumbdunce]

throw out your 9" idea, a 9" is no stronger than the toyota diff. the GQ isn't much stronger than the toyota job either.

I figured the H260 would have been a fair bit stronger than the cruiser diff, and as a leaf diff should be easy to fit, but agree with your point especially in relation to the 9"

Steve.

since he's talking coils I assumed he meant H233B? but yes agree a H260 is definitely stronger (if you can handle losing that much clearance ) don't all coily GQ's have a H233B? (I'm no patrol expert!)

think also the patrol leafs are a bit further apart than the cruiser, so would have to move the perches on the axle anyway? also a fair whack wider than the cruiser, which would be coolish - would have to do something with the front to make it match up though.

[Gwagensteve]

I believe the 4.8 GU has a H260 coil, but semifloating (?)
The leaf H260s are full float I think, and I agree would make a cool swap, but a suzuki on stock tyres would probably have more clearance

I don't believe that coil GQ rear H233B is much different to a cruiser in strength.

I didn't realise open cruiser rear diffs were 2 gear - no wonder they're suffering with 35's and a 350.

Steve.

[dumbdunce]

I believe the 4.8 GU has a H260 coil, but semifloating (?)

Nissan calls it 3/4 floating, their argument being there are 2 opposing tapered roller bearings at the wheel end, so although the axle and wheel flange are a unit, a broken axle does not necessarily completely immobilise the vehicle. even 3 litre GU's have the 10" diff.

The leaf H260s are full float I think, and I agree would make a cool swap, but a suzuki on stock tyres would probably have more clearance

yes. strong but aguably less useful off road.

I don't believe that coil GQ rear H233B is much different to a cruiser in strength.

shhhh don't let a Nissan guy hear you say that!

I didn't realise open cruiser rear diffs were 2 gear - no wonder they're suffering with 35's and a 350.

yes, almost all of them. there are a very few 4-gear open diffs in toyotas but the vast majority are 2 gear open (pre '89) or 4 gear LSD. by the time most 'serious' 4WDers upgrade to 35's and/or a V8 they would have added things like diff locks. So this is where I think the problem lies - "gentle" driving with the 350 could well be the equivalent or harder on the diff than revving the 2F and popping the clutch. it's all relative. the bottom line is, if spider gears are the problem, a 4 spider diff may well be part of the solution. even just grab the LSD at out of a 6x/7x/8x series and pop it in the next diff before it gets installed, make sure the backlash and preload on all the bearings is good, and you'll have a happy diff. Even the hilux 8" diffs can handle 400+ horses so a cruiser 9.25 should have no drama with a 350.

[j-top paj]

the 4.5 came with the h260 also. not sure about all of them, but mine did

[jessie928]

...we will either put a GQ diff in and convert it coil rear or get a 9" cut down with a detroit locker.
.

throw out your 9" idea, a 9" is no stronger than the toyota diff. the GQ isn't much stronger than the toyota job either. (wait for the patrol boys to start whingeing about that, but it's a fact; the main reason patrols blow them less often is less torque from the patrol motors) if you are busting spider gears, it's probably driving habits - not necessarily too much right boot, but too quick on the clutch/changing hard and fast, or lugging the motor in too high a gear, which is easy to do with a motor that makes good torque. an easy fix is to get your hands on a 4-spider diff (which will probably be an LSD) from a later model cruiser, eg just about any cruiser from 1989 on, and if you can get one from an 80 series, they have a stronger case and bigger carrier bearings too. bolt in, although you may have to drill the flange to suit your tailshaft.

Alternatively, fit a detroit or airlocker to the stock diff.

buy yeah 3 diffs in a short time = driving habits. if you were snapping pinions it would be a suspension problem, blowing crownhweel/pinion gears could be bearing problems, spinder gears *might* be excessive spider/side gear backlash but 3 times?

mate you gotta be joking when you say that a 9" is no stronger than a cruiser diff.

I spat out diffs in 40's like banjo's behind a big block...
in my first 40 that i put a warm clevo in, spat out transfers to.

the only thing i have ever done to a 9" ford diff with 31 spline axles is twisted the axles with a big arse 351 clevo

patrol diffs however, shit on cruiser and probably better than and at least on par with the 9", and then enter the H260 GAME OVEr.........

before you brush me of as a patrol driver, i have 3 landcruisers.


in regards to the first question, is your mate replacing the entire centre or is he just changing the spider gears and shafts?


Jes

[cruiserkid]

We have been just boltiing in new centres.
The first one was the original one that was in the vehicle when he bought it.
The second one was a spare I had laying around out of a BJ70.
And the one we blew one the weekend is out of the front of a HJ60.

I dont know a lot about the internals of diffs, but from what I have been told it is the cross pin that keeps breaking which is then destroying the spider gears etc.
If that makes any sense to you.

[Ruffy]

Definetly don't waste your time doing a 9 inch conversion.
So far Dumbdunce has given you the best advice. Look for a late model diff centre. If it's side gears then its driving style.
Somoe silly questions.. Both rear tyres are the same brand and size???
I know it's silly but i've got to ask!
Spinning inside wheel arounds corners??
One wheel spinning while the other is stationary will cause it which is a driving style issue. Also snapping form first to reverse when bogged.
Good luck.

[cruiserkid]

It has got all of the same size/brand tyres on it.
I have spoken to a few people also who have recommended the later model diff with either a LSD or put a locker in there.
That looks like the next thing to try.

Thanks for all your help guys, you have been a BIG help.

[-Richo-]

how do people come to the conclusion that ford 9" diffs are weaker than or equal to toyota 9" diffs?

[Cruza62]

Air lockers are designed to outlast the axles....! Go get one and you won't break it, but then you may start shearing hub nuts etc, then buy a kit to convert to tougher hubs...

[ISUZUROVER]

how do people come to the conclusion that ford 9" diffs are weaker than or equal to toyota 9" diffs?

Because a stock 9" really isn't that strong. Sure, when you upgrade to a nodular iron case and 31+ spline axles they are VERY strong, but you are talking big $$$. Stock for stock they are probably about the same.

Not all drag racers use 9" diffs - some use toyota and nissan diffs!!!

[scout392]

how do people come to the conclusion that ford 9" diffs are weaker than or equal to toyota 9" diffs?

Because a stock 9" really isn't that strong. Sure, when you upgrade to a nodular iron case and 31+ spline axles they are VERY strong, but you are talking big $$$. Stock for stock they are probably about the same.

Not all drag racers use 9" diffs - some use toyota and nissan diffs!!!

I have heard the same a 28sp 9 inch is good but it not great.
Also i would have very littel faith in the early cruser diffs running a v8 even a small block. Then you add big tyers and a heavy right foot... there goes and other one

Eric

If you dont want a Nissan diff in your toyota, try a after-market center or weld the spider gears UP

[Shadow]

how do people come to the conclusion that ford 9" diffs are weaker than or equal to toyota 9" diffs?

Because a stock 9" really isn't that strong. Sure, when you upgrade to a nodular iron case and 31+ spline axles they are VERY strong, but you are talking big $$$. Stock for stock they are probably about the same.

Not all drag racers use 9" diffs - some use toyota and nissan diffs!!!

I have heard the same a 28sp 9 inch is good but it not great.
Also i would have very littel faith in the early cruser diffs running a v8 even a small block. Then you add big tyers and a heavy right foot... there goes and other one

Eric

If you dont want a Nissan diff in your toyota, try a after-market center or weld the spider gears UP

There are crap loads of 40 and 60 series getting around with 253's and 350's and they dont have any problem with diffs as long as you'r not pulling line locks or dumping the clutch.

[Gwagensteve]

how do people come to the conclusion that ford 9" diffs are weaker than or equal to toyota 9" diffs?

The only advantage of the 9" diff is the pinion support bearing, and the amount of heavy duty equipment available for them. Otherwise, you have a 28 spline 9" ring geared diff, which is pretty comparable to stock cruiser or patrol.

H260 patrol runs 37 spline shafts and a 10" ring gear and is pretty close to dana 70 in strength.

The very low pinion doesn't make them as suitable for off road use IMHO as japanese diffs.

Sure, there are high pinion versions, nodular 3rd members, 31 spline conversions etcetc, but there are lots of $$$ with all this stuff.

Steve.

[sierrajim]

We have been just boltiing in new centres.
The first one was the original one that was in the vehicle when he bought it.
The second one was a spare I had laying around out of a BJ70.
And the one we blew one the weekend is out of the front of a HJ60.

I dont know a lot about the internals of diffs, but from what I have been told it is the cross pin that keeps breaking which is then destroying the spider gears etc.
If that makes any sense to you.

Part of the problem could also be that none of the above sound like "new" centres. They sound like diff parts of unknown history that have been lying around in the shed for who knows how long after being fitted to a car with unknown use.


Dumbdunce and Gwagensteve, could this be a technical match made in heaven?

[cj]

Dumbdunce and Gwagensteve, could this be a technical match made in heaven?

[DR Frankenstine]

An old mechanic told me that spider gears breaking is caused by excessive wheel spin on one wheel. Apparently cruiser diffs are prone to it.
Because of poor lubrication to that area spinning one wheel up actually causes the gear to seize to the spider gear shaft, then it has nowhere to go but bang.
He says you shouldn't spin up one wheel for any more than 15 seconds, In mud or on bitumen or whatever. Hope this helps and it does make sense.

[Gwagensteve]

An old mechanic told me that spider gears breaking is caused by excessive wheel spin on one wheel. Apparently cruiser diffs are prone to it.

I thought it was a bigger problem for hilux drivers

Because of poor lubrication to that area spinning one wheel up actually causes the gear to seize to the spider gear shaft, then it has nowhere to go but bang.
He says you shouldn't spin up one wheel for any more than 15 seconds, In mud or on bitumen or whatever. Hope this helps and it does make sense.[/quote]

15 seconds

Steve.

Just having a stir

[DR Frankenstine]

Ok lets test this

Anyone who's got blown spider gear diff centres laying around have a good look see. See if there is a seized gear on a shaft.
I'll bet there is.

[jessie928]

a possible easy fix would be to machine down the shaft and install needle roller bearings ?

JEs