Corona RT142 Diff Advice

[Toyocorona]

Hey all,

First post - but I've researched the forums here extensively - has been very helpful.

Okay, to the point -

I've got an 1985 Toyota Corona Avante Auto with IRS, which, from info I've gathered from forums here would be a full imported version (ie. blue/grey interior).

Anyway, I've got issues with the diff - whining slowly getting louder - got it looked at out here and they reckon pinion worn ie. 'needs new diff'.

What are my options? I understand that I should have an F372 diff in my car, with a ratio of 3.583...and I've found that some F series diff centres are interchangeable? Please tell me if I'm misinformed. (I've had the car for about a year now...)

So, in short, what is the least hassle way to replace my diff/diff centre. Should I simply hunt down another identical diff, get this one rebuilt or is there some other mod that would be more effective? Just a note: I use this car mainly for cruising - I've just moved to rural Queensland from Brisbane so I rarely drive under 110km/h for very long...

I appreciate any help!

Thanks,

Toyocorona.

[sleepy1g]

mines running a 4.1 lsd out of a ma61 in it, according to the previous owner.

so they should fit i do believe that some of the celica's run the same centre even though they are live axles.

[wilbo666]

F series IRS.

Many cars come with F series IRS diffs that will bolt in (the whole IRS unit) .

Getting a whole new IRS diff is by far the easiest IMHO...

MA61 Supra
RA65 Celica (Not RA60 or SA63)
RT142 Corona IRS
MZ1x Soarer (Not MZ12 Manual in case you manage to find rocking horse shite )
MX73 Cressida
etc

Cheers
Wilbo

[sleepy1g]

awesome info wilbo widens the field for more spares for mine too

[The Witzl]

If you are doing a lot of highway driving now - i would recommend not shortening the diff ratio, keep the original 3.5:1 or whatever your RT142 originally had.

The MX73 cressie would be my pick - will likely have a longer ratio, and is less likely to have been thrashed during its life.
If you want to have fun, you could put the LSD centre from an MA61 with the gears that match your RT142... and have LSD

[Toyocorona]

Thanks for the insight!

For my current situation I'm going to look at just replacing the whole diff. I really don't want to shorten the ratio at all, but I guess I'll have to take the first option that comes my way.

At this stage I don't have time or money to be picking and choosing...as long as she runs!

[timbosaurus]

what was the difference between buying an IRS and non-IRS avante back in the day?

Was it just a tick in the dealer option chart, or an early vs late thing?

[wilbo666]

what was the difference between buying an IRS and non-IRS avante back in the day?

Was it just a tick in the dealer option chart, or an early vs late thing?

Early vs late (IRS) to my knowledge


Also, this may help...
RA65/RT142 manual is 3.58
RA65/RT142 auto is 3.727
MA61 manual is 3.9 (clutch LSD)
MA61 auto is 4.1 (clutch LSD)
MX73 auto is 3.9 (if I recall correctly)

Cheers
Wilbo

[Toyocorona]

Early vs late (IRS) to my knowledge


Also, this may help...
RA65/RT142 manual is 3.58
RA65/RT142 auto is 3.727
MA61 manual is 3.9 (clutch LSD)
MA61 auto is 4.1 (clutch LSD)
MX73 auto is 3.9 (if I recall correctly)

Cheers
Wilbo

Hang on a second - does that mean that my diff is 3.727 NOT 3.58? Mine's auto and from research I had noted down auto was 3.583...please confirm?

[brett_celicacoupe]

you can use a gearset from a live axle F series if you like.

ie YR22 tarago, MS112 crown etc


another potential IRS diff donor is MS123 crown and MZ10/11 soarer

[Hen]

Easiest way to tell what you have is to read the build plate in your engine bay. Motor/trans should read something like: 22RE/F372. It's the F372 bit which is the diff code.

Then check out one of these pages and see what the diff code means.

Conceivably the diff has been changed in the car's life (so counting revolutions of tailshaft to wheels is the only 100% definite way to tell) but I'd say it's unlikely.

Hen

[old_school_jap1]

in my experience the live axle gearsets won't work in the irs housing- different crownwheel offsets. but the centres bolt straight in

[sleepy1g]

when you say early vs late for the irs what is considered early and what is considered late

[wilbo666]

when you say early vs late for the irs what is considered early and what is considered late

From memory it is 85-> ? (Don't quote me )

Cheers
Wilbo

[brett_celicacoupe]

Easiest way to tell what you have is to read the build plate in your engine bay. Motor/trans should read something like: 22RE/F372. It's the F372 bit which is the diff code.

Then check out one of these pages and see what the diff code means.

Conceivably the diff has been changed in the car's life (so counting revolutions of tailshaft to wheels is the only 100% definite way to tell) but I'd say it's unlikely.

Hen

i think for some reason some of the RT142s dont have the toyota manufactured plate that has that info. ie they have W55s but not many people know because it doesnt say explicitly anywhere