truck with expensive tastes, Help with toyota front diff

[skid4x4]

hi guys, well after a long time my project nissan has finaly been driving around for the last few months and beating in new springs nicely, however i started with 4.3 ratio diffs std lux 8inch in back and prado high pinion in the front, went fine for a good 2 months of river/sand/mud/shingle beach, and deep water xings
then...
after blowing a turbo in a water hole i replaced it and lightly boosted her a bit more, took it out that night and shore 4-5 teeth off the front crown wheel,

so had to get a pair of diff nugs from a mates wreck at 4.875 ratio which is good, fancyed some lower ratio ones,

next mild trip was ok, 1 hour cruisy off road,

following trip did a cv and seized a steering box on the same uncomfortable angle, fixed that the next morning after camping out, (not wanting to abandon the ute at this time of year),

went out that night and snowballs chance in hell but this time i blew 6-7 teeth of the crown wheel,

now these high pinion jobs are supposed to be the ducks nuts as they run of the drive side as a pose to the coast side when in the front, well i would hate to think how long a low pinion would have lasted in the front as the second high pinion did well under 100kms with 4x4 engaged????

does any one have any ideas or advice as to why im blowing these things like birthday candles? i set one of them up and was correct with back lash ect, but the 2nd one came strait from a set up truck,

id like to say its my nissan power too much for the yota diffs but i know people run alot more power that a 2.7deisel turbo thru these diffs,
any thorts graciously accepted


91 navara double cab, fliped hilux SAS, rear hilux beam, winch, extreme lift, front, rear and side protection, xtended breathers, a/c compressor, 33's, hi steer kit, rancho adjustables, snorkle, and all round tuff truck

[gimmemud]

Did you happen to be reversing when they went bang? Stronger going forward but weaker going backwards.

[coxsy]

maybe a safari front diff would of been better

[mudlva]

Trails boys are now cutting the heads out and installing cruiser diff heads in there place
Just an idea

[rokhound]

Do you happen to drive like a lunatic? (foot right up it)

[skid4x4]

cheers for that guys,
think the second one did go bang while in reverse, and the 1st i was bordering on getting stuck in soft gravel, so going back and ford but cant say i remember exactly when it went bang,

i have had the thort of a safari or cruiser diff, and now its just a case of how i want to spend a ship load of coin i guess,

either going for stronger gears eg after market hardened crown wheel and pinion,

or getting a front beam from a rustafari, or cruiser,
with the SAS on mine i had to cut the swivel hubs off and flip the beam then re weld outer balls back on in the new position to get the diff head over to the left hand side to meet my drive shaft and stay away from the engine sump,

so changing to cruiser or safari would take a little more than just a beam swap,

unles when you say cutting out the hilux head and putting in a cruiser one do you literaly mean putting the bigger diff head into the original beam??

just a bit pissed as none of the luxes or prados ive gone monster trucking with seem to have any troubles with shearing teeth off, and theyv had bigger tires, motors, lockers and all,

thanks for ideas so far guys, will try get some pics of the beast up in my profile soon

[skid4x4]

And rokhound, good thort but na in my opinion i drive resonably carefully to be nice to my drive line and also i believe that any idiot can get up a bank or thru a hole at 30kph but i prefer to use angles, skill and my articulation to get me places,

[rokhound]

And rokhound, good thort but na in my opinion i drive resonably carefully to be nice to my drive line and also i believe that any idiot can get up a bank or thru a hole at 30kph but i prefer to use angles, skill and my articulation to get me places,

You have to ask the question, there are plenty of dumb farks who think that that is what wheeling is all about
I am running a 5.0ltr inj 8 on 40" tyres through dual transfers and auto (massive amount of torque multiplication) and have never blown a front diff head, and I use a std 4 pinion , 4.56 , 8" lux head with lockrite.
You may want to check that housing you are using does not have deformation issues. Drive shaft is correct length? ( ie not bottoming out).
It seems strange that you should be blowing these with a 2.7 oiler, and I am picking there will be drive line set up problem somewhere.

[IcedJohnno]

cheers for that guys,

with the SAS on mine i had to cut the swivel hubs off and flip the beam then re weld outer balls back on in the new position to get the diff head over to the left hand side to meet my drive shaft and stay away from the engine sump,

What did you use for an alignment jig when you did all those mods and welding?

I am wondering if you housing is misaligned and therefore the 1/2 shafts are fighting the differential carrier.

I bent my rear 1/2 shafts and had issues with that alone. I managed to check those in my lathe and straighten them via both using a press and through peining them.

I have modded 9' Ford diffs before and even using a solid jig on bearing diameters you can get quite a lot of distortion.

[kbjj]

I'm running a 4.8 8" Prado hi pinion diff in the front of my TD27t Navara, and I've done the same to 2 crown wheels within 6 months.
1st one I put down to the fact that my axels were too long (due to setting custom housing up with open head, then fitting an lsd) which side loaded the carrier, spun the bearing on the journal, lost preload, cocked up backlash, bang!
2nd one I blammed on my setup initially. I found it before it went bang while changing a cv. It looks like its been loading the outer tips of crown wheel and cracking off bit by bit. I have just fitted an E locker from an 80 series cruiser, with a 4.8 gear set from Precision Gears USA. Rick at 4wd Accessories brought these in for me. When I set this head up, I asked Rick to check it for me. It was spot on, maybe a touch too much preload on the pinion, but fine for a front diff. So i don't believe my setup caused it.
So... I'm putting it down to weak arsed toyota shit ... I'm really not sure. Rick has told me that the Precision gears are 5 times stronger than factory ones. I'm hopeing they are.
I have rechecked my housing alignment, at it was pretty close to true, but is now spot on. I think it would have to be a wee way out to be a problem. Deffinately worth checking thou. A workmate has told me that some track race cars ( his brothers and others) that are running hilux rear ends, tweak the diff tubes to give them a little positive camber, with no problems that he's aware of.
Hope this helps
Wishing I stuck with a Safari diff
Oh and PHOTOS

[De-Ranged]

I've seen some really bent housings come in... bent enough to make it difficult to get the inner axles out and there has been no problems with diffs...
If anything I'd say you could possibly be binding against the elocker center and the inner axles but you measured that... that could load up the diff carrier changing the set on your crown pinion but that sort of loading I'd expect you to do CV's.... have a look at your brass inner axle bush on the stub axle see if it has odd wear, burnt grease or temper marks from excesive heat thats the only thing I can think off

Seems odd for a desiel and nice driving hmmmm

[skid4x4]

hi again guys, thanks for all your replies, have been away for a couple of days 2wding haha, and talking with mates about the time the diff blew and being reminded of a few bits of the day i forgot may have helped,,

before going i rechecked the allignment of the housing ect the best i could, i was flipped and rewelded by engineers who made a jig for the perpose, the drive shaft definatly not bottoming out on full travel, but the dust cover around the spline was dented and could have prevented full travel, with it off or not dented the travel was fine thou, it has seemed to have taken a knock and front drive shaft may be well out of balance, not siure if this could contribute to blowing diffs at low speeds,

but over this new years away trip my mates did bring up the fact the 2nd diff head was out of a 250000km truck, and also the moment i blew it while being towed out of a sand hole the front brakes were jam packed with enough sand and stones to lock front wheels and break one brake calliper now this must put tremendous strain on a high pinion going back wards,

was thinking of trying a hardend set crown wheel and pinion and hoping like hell my luck changes as well as balance drive shaft again, get diff allignment double checked and fixed if need be, (can any one recomend the best place for that in chch?)
fix a broken engine mount, also noticed this 2wding weekend, and then if still have diff troubles will upgrade to bigger and re think how im going to do it,
putting it down to hopefully a serries of misfortunes that wont keep happening,

engine mount was noticed when reversing in 2wd and sliping a bit i could still hear it from the front which i found weird with no drive shaft in... wondering if a bit of jump then load with brocken engine mount could be attributing aswell to sudden load on diff,

all up still a shit load to check and work on the a crown wheel ect to get from aus, not bad priced, then see how it all goes from there,

please keep ideas and opinions comming as i value them all, thank you and happy new year all

[Bulletproof]

A couple of questions

What were your Teeth marking like when you set the diff up ? were they in the middle of the teeth up and down. It is not as important for toe and heel

How much preload did you have on the side carrier bearings ? Normal is 1 1/2 holes. It is better to increase that for hard 4 wheeling to 3 holes

Are you running a solid spacer?

I'm like Rokhound and have never blown a diff and are running 4.55s with a supercharged 3 litre and 35x11.5 Simex tyres

Cheers Richard

[skid4x4]

the 1st diff i blew i had set up my self with the factory specs and a solid spacer, had my uncle check it (mechanic of 55years)
and teeth markings were good in his opinion too,

2nd diff head was strait out of one and into another i checked backlash and markings but didnt undo anything,

2nd one when it blew it had completely busted about 6-7 teeth but not a single deformation with any of the other 32 teeth,

Bulletproof... are you also running twin cases? wondering although your torque multiplication would be huge compared to my wee deisel burner and std g/box would the low ratios of twin cases lessen the shock and sudden load as your able to ease on where as i can only ease on so much without being hard on my clutch?? just a thort

[Bulletproof]

No I only have one box .

If it only happened to one diff I would say something was bent but because both have had the trouble that would be unlikely.

Have you counted the teeth to make sure you have the same ratios front and back ?

Jafa is running 40inch Iroks on 8 inch toyota diffs without a problem but he has increased his preloads

Are you giving it flat out revs and then dropping the clutch ?

Cheers Richard

[hosehustler]

I had diff problems with my old supra powered hilux shearing off teeth front and rear and of course the blowing of CV's, I was running 5;29's out of old hiaces and there was the problem.....they were all "old" replaced the gearsets in them with some trail gear ones and stuck in a set of longfield CV's and never had a problem from then on.
I'm now running similar set up as Rok, (no dual cases tho) in a hilux, inj 5.0L V8, on 8" 4.88's and Longfield superaxles...been all good you just have to button off when wheels get airborne.

[skid4x4]

yeah definatly the same ratio both with the 1st ones and the second ones were a matching pair from same truck then into mine,

and no not dumping clutch at full note either,

i have noticed the break pattern on the teeth is rather interesting, if this helps im not sure, the pattern the teeth are broken in are as follows,

IF i was in reverse then the outside has chiped off a tooth 1st then the next tooth is missing from outside to about middle, next 2 teeth missing completly then the 5th tooth is broken from the middle to the inside of cw then last broken tooth only missing a bit on the inside,

obviously if i was going foward then that pattern is different and has broken from inside to outside,

this is the 1st diff i blew, will check the 2nd one later as its back in the housing at the mo to keep the dirt out when i was 2wding,,

also got camera on charge and will try get some pics of the break pattern up soon,