8 inch Toyota diffs

[Bulletproof]

Is anyone using one of these gusseted diff housings ? They are used in the states for the tundra's and V6s.

As well as the big bearings the housing is trussed to stiffen the small pinion bearing and the carrier side bearing have the gusset to stop flexing.

The strong one is on the right



Rear View of the gussets



A picture of the gusset




Does any truck in NZ run this type ?

Cheers Richard

[1MadEngineer]

They are really hard to find anywhere apart from the US.

Are you blowing diffs regularly? Are they setup properly?

The problem is 99.999% of guys and diff shops don't know how to set one up! Once they are fitted with a solid spacer and the pinion depth is set, You need to adjust the carrier bearing adjuster with the correct amount of preload. Generally everyone just gets them firm'ish and thats it. BUT!!!! They need to be REALLLLLLLLYYYYY FARKEN tight. EG: the YUKON gear install sheet recommends 150-200ft/lb of torque. So basically we made a little tool with 2 prongs which fit in the adjuster holes and has a socket welded to the center, so we can fit a torque wrench. Then clamp it in the vice and literally jump up and down on it!!! 200 ft/lbs is pretty much my whole weight hanging off the end of a 1/2" breaker bar.

If setup this way it increases strength upto 80%. Due to the fact it pre-stretchs the housing so it can't deflect any more! Don't worry the side bearings can take it..... hey if you little kingpins can hold up the front of the rig then these will $hit it in!!

Try it and see.... you will be surprised. We have done 15+ comps running 37-40" sticky compound comp spec tires and 0 failures.

cheers
Greg

[Jafa]

They are really hard to find anywhere apart from the US.

Are you blowing diffs regularly? Are they setup properly?

The problem is 99.999% of guys and diff shops don't know how to set one up! Once they are fitted with a solid spacer and the pinion depth is set, You need to adjust the carrier bearing adjuster with the correct amount of preload. Generally everyone just gets them firm'ish and thats it. BUT!!!! They need to be REALLLLLLLLYYYYY FARKEN tight. EG: the YUKON gear install sheet recommends 150-200ft/lb of torque. So basically we made a little tool with 2 prongs which fit in the adjuster holes and has a socket welded to the center, so we can fit a torque wrench. Then clamp it in the vice and literally jump up and down on it!!! 200 ft/lbs is pretty much my whole weight hanging off the end of a 1/2" breaker bar.

If setup this way it increases strength upto 80%. Due to the fact it pre-stretchs the housing so it can't deflect any more! Don't worry the side bearings can take it..... hey if you little kingpins can hold up the front of the rig then these will $hit it in!!

Try it and see.... you will be surprised. We have done 15+ comps running 37-40" sticky compound comp spec tires and 0 failures.

cheers
Greg

Well there ya go Richard, someone else who uses the same method as me ya need to turn the adjuster wheels about a quarter turn more than the factory setting, ie about 6-8 holes, not 2 like factory. My piddly little 4cyl hilux diffs have held up to 40's so far.

[vvega]

gear clearance is set by the speed at which the gear rotates at for prolongrd periods
if the diff is seeing 100km/h for prolonged periods it will be set differently to something that never exceeds 50km/h
we have tried the pretention method on drift cars and have had numerious heat failures because of it
we now just set them to the book ... and in that application they last far longer than the pre tensioned ones
i blew my as per toyota setup diffs with ease on 35's but IMO it was due to side bearing flex ... i honestly believe that a gusset would have helped no end

just my thoughts

[Jafa]

Gear clearance isnt affected by carrier bearing preload, you still set the gear clearance ie backlash as per normal. If your setting your clearance by just tightening the adjuster wheels then ya doing it wrong . The backlash is still the same amount after you turn the wheels an extra 1/4 turn. I've been through this all before on another thread somewhere, read "Zuk"s webpage on the gears he does, he's done everything from daily drivers to comp machines, and his setups last.
http://www.gearinstalls.com/freshen.htm
http://www.gearinstalls.com/refresh.htm

[vvega]

gear clearance and bearing tolerances
i never said how you set up a diff gear clearances ... just why we have the tolerances
if you overtention a bearing it will heat up ... thats why we have c1 c2 and c3 etc bearings ... there clearanced on there operational speed
or is there somthing that nachi missed in there development of bearings ?

perhaps there billons of dollars of r&d on preloads was a complete waste of time

[vvega]

i do apreciate what your saying about more preload ... i just dont think its a good idea on a truck thats gunna do 1000 odd km @ 100km/h in the next few months

why not just make a gurdle and do it properly ?

[Jafa]

gear clearance is set by the speed at which the gear rotates at for prolongrd periods
if the diff is seeing 100km/h for prolonged periods it will be set differently to something that never exceeds 50km/h
we have tried the pretention method on drift cars and have had numerious heat failures because of it
we now just set them to the book ... and in that application they last far longer than the pre tensioned ones
i blew my as per toyota setup diffs with ease on 35's but IMO it was due to side bearing flex ... i honestly believe that a gusset would have helped no end

just my thoughts

So when you said "gear clearance", you meant "bearing clearance"? or have I missed your drift again

[Jafa]

i do apreciate what your saying about more preload ... i just dont think its a good idea on a truck thats gunna do 1000 odd km @ 100km/h in the next few months

why not just make a gurdle and do it properly ?

Increasing the preload works, and lasts.

[Bulletproof]

I have just been doing some experiments without the pinion and 4.5 holes of the adjuster equals the pinion preload of about 15 inch lbs and it also takes 50 ft lbs of torque to achieve that figure.

The crown wheel is only going about a quarter of the speed of the pinion so 5 holes would be about right with out damage.

I believe excess pressures could cause the bearing cap to be pushed sideways making the bearing not to run true because there is alot of slack in the bolt holes holding the cap.

Therefore the need of the gusset

Cheers richard

[Bulletproof]

Been doing more experiments on the Carrier bearing preloads and distortion.

I fitted the bearings and adjusting rings and tightened them until there was no slack. I then tightened the cap bolts to 75 lbs.
I then set up my dial gauge to measure the distortion between the bearing caps.



I then tightened the adjuster to the factory 1.5 holes and the reading is 1.5 thou

I now double the factory setting to 3 holes and this is the reading of distortion



I then went to 4 holes of the adjusting ring which gave me 15 inch lbs preload,the same as a pinion.
The dial gauge now is reading 4 thou distortion.



I now go to 5 holes which takes just under 60 foot lbs torque to achieve.

The results are 5 thou distortion and a preload of 20 inch lbs






The advantage of a gusset is that there would be no distortion and the carrier bearings would run true and last longer


I have decided to stick with 4 holes so the preload is the same as the pinion which is still over double what Toyota recommends and the distortion per bearing is 2 thou which I think is not good long term

Cheers Richard

[vvega]

pritty much was my point of the first post richard
the gusset is definatly the way to go in a road going 4wd
the higher rotating speed makes a big differance

10 thou total deflection is a lot when you start talking inclination angles at the bearing surface... more so when the bearing surface is designed to run true ..
the more angle the less of the rollers are touching the supporting surface at anytime the less strenght you have

IMO pretentioning does exactly what jaffa says in reducing the crownwheels ability to flex away from the pinon and adds a great deal of strenght
BUT it wont last the millon km that factory settings would last

a gusset gives you the best of both worlds .... wihtout the compramise

if it wasent a issue ... toyota wouldnt have fixed it with the later revisions

[1MadEngineer]

as for doing a lot of k's , each year we load up the trailer with spares and camping gear and tow it ~1200km each way to compete at TUFF TRUCK. We have done 5 TTC's and with mostly top10 finish's against portal/rear steer truggy's and our poor little lux diffs have never failed.
Economically, tightening them is the way to go! hey a new set of gears is ~$400 and a set of carrier bearings is under $100 so even if you had to change bearings once a year its cheaper than a new set of diff gears every 4 years. $100 a year is cheap maintanence in my book.

[Bulletproof]

Has anyone investigated getting a second hand Gusseted one from the States. They are what is called an 8.5 diff but still run the 8 inch crownwheel with a slightly bigger Dia pinion to stop pinion flex and shims to adjusted the carrier bearing preload.

I doubt that it would be very expensive.

Cheers Richard

[vvega]

what size is ther side bearing ? same as the v6 diff ?
could try to get a deal of tnz just for the gusset/retainer plate
ill make some enquirys and get back to you on it

and as was stated in a previous post
we tried the pretentioning on drift cars and had massive issues with overheating bearings and binding
so in my experance it depends on the application
but really ive yet to see a reasnoble arguement put forward as to why a gusset is not a better idea ...
i mean in terms of numbers and engineering .. its stands miles above just crank that shit up mate.. or is wanting a better solution ... not ok

[1MadEngineer]

but really ive yet to see a reasnoble arguement put forward as to why a gusset is not a better idea ...
i mean in terms of numbers and engineering .. its stands miles above just crank that shit up mate.. or is wanting a better solution ... not ok

I agree, an nice 8.5 would be sweet, but sadly from my research, they are quite expensive. As you need a complete housing due to the third member being larger in diameter. Yes they are super tuff, and i would give my left nut for one, a 30 spline pinion sounds very nice . We prefer $v$ to just make 60/lux diffs ATM as toyota 9.5's are cheap as (eg 60series diffs are ~$50-$100 max) then splice the centers onto IFS lux tubes. We have found the Lux OEM axles to be the strongest option by far. The aftermarket chromos are not as good as the stockos, sure they look beefy, but the material and hardening process is just not right. The other diffs we use are the Nissan H260's - 260mm / 10.25" dia ring gears 37 spline axles mega beef! but the material in the nissan axles is pathetic and are IMO proving to be less than 10% stronger than the lux ones. Also the pinion bearings (small one) is the same size as toyota and H233 so no real strength upgrade in that area.
So after all the $'s and stuffing around our 60/lux diffs seem to be the strongest $v$ so far, and parts are cheap and everywhere....

[vvega]

absolutly
when i blew the 8's in my truck i looked for another alternative (i didnt even know about the 8.5's)
so ended up with 9.5's ... i still kinda regret the loss of ground clearance
..
interesting what you say about hardness .. when i was doing NDT for PAC its was quite comon to get a variance of 15% in rockwell from our manufactured items(from the same material batch) ... ... of all the toyota rods, cranks etc i tested(homers) they would have been within 2% varaiance max

im still waiting on some pricing
cheers

[Bulletproof]

absolutly
when i blew the 8's in my truck i looked for another alternative (i didnt even know about the 8.5's)
so ended up with 9.5's ... i still kinda regret the loss of ground clearance
..
interesting what you say about hardness .. when i was doing NDT for PAC its was quite comon to get a variance of 15% in rockwell from our manufactured items(from the same material batch) ... ... of all the toyota rods, cranks etc i tested(homers) they would have been within 2% varaiance max

im still waiting on some pricing
cheers

Hi Wayne
My neighbours son has the top off roader in this part of the world which is a Tundra and he is a support mehanic for the race across the mexican dessert.

I will talk to him over the weekend about Tundra diffs because they bring in containers from the states for the race to the sky at Queenstown. The last container had 40 sets of 38 inch tyres.

I am personally with you all the way on these diffs, if the price is right because you don't loose ground clearance.

cheers Richard

[Bulletproof]

The gusseted housings are ones are available through Yukon.

I talked to Andrew this morning who has 2 Tundra diffs in Christchurch. He is going to measure the size for me to see if they will bolt straight into a Hilux housing.

If they will bolt straight in a person would only have to modify the bowl at the back to give room for the gusset

Cheers Richard.

PS Andrews Tundra offroader has 550hp and he is running Special alloy 9.5 diffs from the States and blows them all the time .

[1MadEngineer]

The gusseted housings are ones are available through Yukon.

I talked to Andrew this morning who has 2 Tundra diffs in Christchurch. He is going to measure the size for me to see if they will bolt straight into a Hilux housing.

If they will bolt straight in a person would only have to modify the bowl at the back to give room for the gusset

Cheers Richard.

PS Andrews Tundra offroader has 550hp and he is running Special alloy 9.5 diffs from the States and blows them all the time .

the 3rd member face (bolt pattern) is much larger std 8" (almost as big as 9.5"). And they only fit there own housings due to the increased depth as well.