AE86 T series diff questions

[Stealer Of Souls]

Okay.

One.
Are the T series known for having a crown wheel and pinion "weakness". I have just worn out a crown wheel and pinion in my T series rear end. The original one in the diff was worn. The first second hand replacement didn't last long (was a little whiny to begin with), and the latest one did better, but is now also a bit goneburger...
In all three cases is seems that the crown wheel and pinion have worn the top hardened surface away and are now grinding.

Two.
Are all RWD final drives helical cut? Why can't the be straight cut? Especially if being used in a more heavy load situation.

Three.
With my Crown wheel and pinion goneburger I'm faced with something of a decision. The second part of my problem is that one axle has a slight bend in it. Just enough to be a pain in the A.
I'm faced with the thought that perhaps i shelve all the current bits for my other car and replace the guts with the late model gear.
Will this work. I have an early model housing and want to put all late model gear on the inside.
Is this a definite 100% guaranteed straight swap. Just buy the late model LSD, axles, and bearings and put it in? Or do you need to change other fiddly little bits?

[Mr Revhead]

1: any diff will if not set up right. the T series is no different. they are known for wearing fast if not getting enough oil, just like anything.

2: noise, strength. helical = more surface area meshing

3: housing is the same, so yes.

[Burning Angel]

afaik helical has less surface area in contact at any one time.
although there appears to be more contact area only a small portion of that is contacting at any time which is why their quiter. straight cut gears contact along the whole length of the tooth and are hence noisier.

im pretty sure this is right but feel free to correct me(or maybe im interprting #2 wrong)

[Stealer Of Souls]

afaik helical has less surface area in contact at any one time.
although there appears to be more contact area only a small portion of that is contacting at any time which is why their quiter. straight cut gears contact along the whole length of the tooth and are hence noisier.

im pretty sure this is right but feel free to correct me(or maybe im interprting #2 wrong)

This is my understanding... It just interests me that no one makes straight cut crown and pinions.
If I've manage to have three sets of crown and pinion that suffered the same fate...

Are the AE86 race cars suffering the same fate?

1: any diff will if not set up right. the T series is no different. they are known for wearing fast if not getting enough oil, just like anything.

This diff was set up by some very reputable and trust worthy people. And neither my mechanic nor his diff person can see why it would be suffering oil issues.


All in all I'm just trying to make sure that my best option is to just get a replacement crown wheel and pinion, and not search for some "custom" arrangement.

[frost]

no its the other way round. helical has 1.5 tooth touching at any one time and straight cut only has 1 tooth touching.

[frost]

you fix will be installing a LSD. and over fill the diff oil from one side of the axle.

[Stealer Of Souls]

I've already got an LSD.
I will suggest overfilling the diff.
Thanks.

[NZ_AE86]

I have never had any Diff problems with mine. It's used for Track/Rally/Sprints.

Straight cut gears have less contact then a helical cut gear of the same width.
They are not always stronger either!

[Drifter4ag]

get a brand new crown and pinion if you love the t series so much .. normal road use wont bust the c&p unless set up wrong or less than fact1ory oil level...

over fill it ...2litres +
get a hilux ! or an f series

[Stealer Of Souls]

get a brand new crown and pinion if you love the t series so much .. normal road use wont bust the c&p unless set up wrong or less than fact1ory oil level...

over fill it ...2litres +
get a hilux ! or an f series

Okay. Because I'm a tard...
What does an F series come from? Whats the differences between an F and a T.
And it's not that I like the T that much. But it is what comes from an AE86. It has sentemental (sp??) value.