Mythbusters - S and T series diff strength

[myne]

whereas other people with less power (if you can say a K series has powah ) broke MANY axles with a locked diff,..... but never centres....

Blown 3 diffs and 6 gearboxes with K engines. The borg warner diffs were MUCH stronger than the banjo's though.
That was in the period where I was doing 1000+ km a week, in a car with less horsepower power than a maimed melbourne cup loser. What little power it had was thrashed for all it was worth. Never had one die during a burnout though.

[oldcorollas]

for all these people that break centres.....(i mean pinion/crown/whining etc)

how many actually set the backlash and preload correctly?

[Toycrash]

And how meny or you have removed pinion gear flange, and installed it by guessing the right tightnes...

Why blaim some part for weaknes, if the real fault is done by own stupidity (on missassembling or deliberate abuse)

[slide86]

or use of rattle gun or large bar......tightening torque = FT

[TheToyman75]

Incorrect diff set up is easily the biggest cause of diff centre failures in the T series diffs. Lets face it at Less than $100 for a second hand centre how many people pay someone lese to set it up correctly for them.

Given most of these diffs are from the mid 70's to Mid 80's it really is no wonder they fail, poor maintenance doesn't mean its a poor product (Man that sounds familiar )

In saying that a welded diff is a retarded idea for anything but a drag car.

T series diffs are not forgiving to abuse, I have destroyed many a T series cente, all my fault due to abuse (Who doesn't love a nice fat rollback burnout when there young ! My current TA22 is the only one I have ever upgraded the Diff in.

The only T series Axel I have ever broken was when the welded centre was left in the pornstar between drag meets. The centre, reat uni joint and axel let go on the line from a 5000rpm side step of the Extra HD clutch.

On the other side tho a certain turbo charged V8 TA22 had a T series LSD diff in it until its latest recreation

[TheToyman75]

You could argue that the T 6.7" crown wheel is stronger than the 6.38" S type, however I feel that the axles are far more likely to let go due to abuse than the crown/pinion.

There are several good reasons to upgrade to a T series rear end, but don't fool yourself that strength is one of them.

Hen

Back to the original statement tho.

Hen, Anyone agrueing that the T seres centre is stronger than the S series centre will win, You can fool yourself about whatever you like lol.

The diffs are of the same design, made by the same people with assumeable the same process. The T series is gears are bigger, thicker, stronger.... The axels are the "same"

Therefore the T series IS stronger than the S series

[Hen]

Anyone agrueing that the T seres centre is stronger than the S series centre will win

It depends who's arguing which side , but yes, I agree.

I'm suprised to hear the troubles everyone has had with centres. I always thought the axles were the weak point, and given the splines, equally weak in both S and T diffs.

Hen

[skaney]

I agree with the majority here, the centres are the most likely part to break.

I have broken 3 S-series centres, none of them were welded and no excessive abuse of the car involved.

I then went to T-series, I had a open T18 centre for a fair while and this thing was quiet as, best condition diff I have ever heard in an AE86, and it came from a wrecker.
I then went to a TA22 centre with a Cusco 2 way LSD set up correctly at a very reputable diff specialist. This car has since had the living bejesus threashed out of it and the diff has no signs of any complaints yet.

My experiance S-series are more likely to break. Axle strength doesnt really matter as its the centre that usually goes (crown/pinion or spiders gears in all my diffs)

[oldcorollas]

i'm surprised any diffs break at all

seriously, the strength of the materials vs the forces going thru them....

most failures do NOT occur by deformation of parts, ie by distrotion of the housing or bearing or gears etc....

most fail by fatigue... ie, a crack is started from one of the many sharp crack starters present (particularly on the splines) and then constant abuse results on crack growth and then failure... even a few abuse events early in an axle or diffs life can propogate to failure with normal driving over a number of years....

[Robbos_Toyotas]

it all depends on the power you want...for reliability id go a hilux diff (g series 8") or a crown ms112 diff (disc f series 7.5")

both of these have readily available LSD's lurking around the wreckers/ this forum.


A t series is plenty strong enough for a mild 4A, but if you want to experiment and be sure the guts of your diff isnt going to be lying at the dragstrip startline, id suggest you upgrade to a larger one like the above. The hilux diff into AE86 has been pretty well covered i think - do a search.

Blake

[brett_celicacoupe]

i would have to comment on my experience with the T series diff. my 1g (gen 3) celica still has the original T series in it and its still going fine. i installed the engine last october so its had about 5-6 months of reasonably hard,day driving. a couple months there i was running 16psi daily as well

this also includes 2 seperate drag occasions(~15 passes in all), one of which i was running 16psi and semi slick tyres.

ive also been to the local track twice during this period. i also remember driving down a private road doing fishies (in the dry) .i could feel the power being transferred from one wheel to another on each flick

its still open centre though


there is a shitload of backlash(about 15degress on the input pinion ) but hardly any whine

long live the T series

[1JZ-Rolla]

Behind a 3TGTE & 4AGTE, i broke several T series centres, never the pinion or ring-gear though, it was always the smaller differential gears that would strip themselves just at the point where the car got traction after spinning one wheel from a standing start.

Only ever broke one axle, which was hardly surprising at the drags with a welded centre & bad shock loads from axle tramp.

I think that the reason I never broke a pinion or ring gear was because the backlash was always set correctly before installation, and I never touched the front nut on the pinion flange (the crush tube that separates the pinion bearings is just too fragile).

[o_man_ra23]

I would have to pay testament to Brett's abuse of his diff. I remember a certain time on a certain road, he was doing fishies in front of me... and i was doing over 100. I too abused many a T series diff with constant burnouts, reversies, powerslides, compression locks, chirped gears, etc etc... and only had one centre complain. when I pulled the diff in question apart, the axles had only light wear on them, and very very slight twisting, whereas the centre was missing 2 crown teeth, and 3 spider gear teeth (came out in the oil). So I would have to say that the centre was the weak point there. Having said this, the current diff I have, the centre was donated from my RA23, which copped new bearings, backlash adjustment and pinion torquing. Its not complained with my 7000rpm clutchsteps (from the 18RG RA23 days) and more recent powerslide every corner possible adventures. Checked everything out when i swapped it into the RA40... no probs at all.

Still going to go to a G series to take the 3SGTE abuse I intend on inflicting tho

Cheers, Owen

[Steve M]

My brother's RA28 has seen a lot of very hard hills driving, but no intentional burn-outs.
We've gone through 2 T-series diffs, one behind an 18R-C and one behind a mildy worked 18R-G.
both of them were 4.1 ratios and broke teeth off of the pinion gear.
The 3.9 ratio is going great with the LSD, it was professionally set up (after we took it back to the guy and told him to do it properly this time!) Diffs shouldn't make grinding noises and vibrate the whole car after being "professionally" rebuilt.

[Robbos_Toyotas]

im a naughty boy.