MA61 Diff question

[UZA61]

hi guys

quick question,

my diff has gone in my 1UZ power MA61 and i need to repair it or swap it for something else.

now the thing is that when it was working i noticed that it was running too fast for the engine and gearbox, it was accelerating insainly fast but it ran out of gear too quick and cruising along in 5th the engine was revving too high.

I assume an Automatic MA61 diff has a longer ratio so that would bring the revs down at high speeds? i also assume its a direct swap for a manual diff?

Otherwise if i rebuild my manual diff are there any other toyotas that you a 7.5" wheel but with a longer final drive to also bring down the revs?

cheers guys, much appreciated

Lee

[brett_celicacoupe]

RA65 celica, RT142 corona and MZ12 soarer have a F series 3.58 diff

"draven" on these forums can get mechanical LSDs to suit for under $700aus

[Norbie]

Yep, I've got a 3.58:1 ratio out of an RA65 and it works great with my 2JZ. Make sure you upgrade the centre while you're at it, the stock one is pretty weak but the TrueTrac helical LSD centre is very tough.

[Draven]

You've gone through how many gboxes norbie? and yet to kill that diff?

[pete05]

My stock F series has gone down hill very fast since fitting the 1j, what the deal with the tru trac centres do they have to be imported or are they around here?

[Draven]

"draven" on these forums can get mechanical LSDs to suit for under $700aus

I can source the truetracs for under $700.

[Norbie]

You've gone through how many gboxes norbie? and yet to kill that diff?

Four gearboxes and counting, diff still good.

[pete05]

I can source the truetracs for under $700.

Cant see it before christmas now, but once thats over i might have a chat with you about getting one, i hope the stocker lasts that long.

[UZA61]

Yep, I've got a 3.58:1 ratio out of an RA65 and it works great with my 2JZ. Make sure you upgrade the centre while you're at it, the stock one is pretty weak but the TrueTrac helical LSD centre is very tough.

Hi Norbie,

Surely a 3.5 ratio would make my revs higher and my top speed lower?

Looking at this thread - http://forums.toymods.org.au/index.p..._view=&start=0 - it looks like ".778 - MS110 crown auto(F362) diff"would be the one to go for?

It would bring the revs down in 5th and increase top speed wouldnt it?

Im getting the True Trac LSD but would be great to lengthen the ratio a little.

Isnt it just the main cog that goes around the diff the one that i would need to change to use a crown ratio on a true trac lsd?

cheers

Lee

[JustCallMeOrlando]

Surely a 3.5 ratio would make my revs higher and my top speed lower?

You have it back to front. It's much taller, so your revs would be lower and top speed off the chart

[Norbie]

What he said. 3.58:1 is a high-ish ratio which is good for torquey engines. What you probably have now is a 4.1:1 which is a low ratio and good for smaller high-revving engines.

To change the ratio you need to swap the crownwheel (big gear that goes around the diff) and pinion (smaller gear attached to the tailshaft). These come as a set so you have to swap both. This is quite separate to the diff centre, which is bolted to the crownwheel.

[TheStitt]

I run a 3.58 in my wagon with a true trak and its a great combination.

With a W57 i still think that it revs to high and doesn't drop to much revs with a W58.

I still want to go lower a 3.2 or so

Ps I overspeed and blew a tail shaft up with 4.1

[Neal_411]

I can source the truetracs for under $700.

Is that for the centre AND the rebuild kit needed to do everything?

[brett_celicacoupe]

nope, just the centre.

you buy the seals/bearings

[UZA61]

Excellent! Cheers guys

Does anyone have part numbers for either

3.583 - RA65 Celica(F372)
or
3.583 - RT142 Corona (F372)
?

I've checked the Electronic Parts Catalogue but cant tell one gear set from another...

cheers

Lee