IS300 diff question

[blueck]

Hi, long time reader first time poster.

I have a US IS300 which has the big pile of monkey spunk known as the W55. At 108K miles it has already decided to give up. 1st is impossible to get into while rolling, 3rd grinds when coming from 4th and 4th pops out of gear after coming from 5th. Also the bearings don't sound to hot anymore. (Can anyone explain why Toyota put this tranny behind a 2JZ? Everyone has problems with it, it just seams it can't handle the torque.)

None the less, I was told by many from my.is that the W58 is the way to go. And I plan on putting one in here shortly but I have a question about the rear end. I would like to upgrade to a 4.30 or 4.27 from a MA70 or JZA80 respectfully. Currently my IS300 has a LSD and I would like to keep it as it works well and its already mine. Could I just swap the ring gear from either Supra differentials and replace my 3.727 gear allowing me to keep my lsd center and carrier?

[Robbos_Toyotas]

hi mate, i think the supra highest gearset out of ma/ jza70 is 4.1 out of ma70 auto non turbo.

all are 3.9/3.7/4.1 - there *might* be a 4.3

The GA70 supra has a 4.54 in the manual and a 4.7 or something in the auto

Obviously the hilux and hiace have short ratios ranging from 4.1 to 4.9 as well if you want. But i think your making a mistake putting something so short in, id stick with the 3.7 - a very nice ratio to have!

You need to find out what diff series you have - is it an A series?

[urantia]

yeah a70's came out with a 4.3:1 diff, i have one in at the moment.

That is interesting that they paired a w55 with a 2jz-ge in the is300, i would of thought they'd have A series diff's but now i'm not so sure.

[cambelt]

it needs the w55 with the 3.7 diff , if your going to use a w58 then 3.9 or 4.11 would be ok .
Dave

[Norbie]

W55 and W58 are internally identical (apart from ratios of course), so there's no reason to think a W58 will be any better if you broke a W55. Most NA Supra owners don't seem to have a problem, strange that yours gave up so quickly. Do you have a big clutch on it?

Anyway, it's highly likely the IS300 has an A series diff so you should be able to swap in a gearset from a NA Supra and keep your LSD centre.

[blueck]

W55 and W58 are internally identical (apart from ratios of course), so there's no reason to think a W58 will be any better if you broke a W55. Most NA Supra owners don't seem to have a problem, strange that yours gave up so quickly. Do you have a big clutch on it?

Anyway, it's highly likely the IS300 has an A series diff so you should be able to swap in a gearset from a NA Supra and keep your LSD centre.

i always thought the same thing, but so many people are having problems with this box in the states on the IS300. i am starting to think it might be from the odd clutch/flywheel that toyota used, it has a solid hub clutch disc with a sprung flywheel. might not be as suited as well as the engineers hoped. this is why i have a 11lb flywheel and a new sprung act clutch kit that i plan on using, but do you think if i just cracked open the w55 and rebuilt her and with this new fly/clutch setup it would last longer? this transmission was already rebuilt by toyota back in 2001 when the previous owner had it, so this would be the second time.

[Norbie]

If you can get a second-hand W58 cheaper than a rebuild I'd be going that way.

It is very strange that IS300's keep killing gearboxes when JZA80's don't. You're right the different clutch setup could definitely have a lot to do with it, as could the extra mass of the car (not sure what an IS300 weighs but I'm guessing more than a Supra).

[Mr Revhead]

something very odd there.....

the dual mass flywheel wont be the cause. its used in many other toyotas, hiluxs, surfs, altezzas and this would be the first iv ever heard of g/b issues caused by the flywheel.

so in the states they sell the is300 with a 5 speed? thats odd to! unfortunatly iv forgotten to load the lexus passwords onto my epc so i cant do any parts cross referencing till i get back to work

[urantia]

is200 are about 1400kg, is300 shouldn't be too much more then that. a tad less then a jza80 i think.

(still not sure if an is200 with 1jz conversion is the way to go or not after learning there weight and how the is300 pales in comparison to the is200 in handeling)

[3sgte]

I worked 5 years at an "L" dealer on that contiinent, and I didn't see a single MT break in an IS 300.

Clutches yes, in fact one guy had 3 clutches put in in less than 100,000 kms.
Never had to touch the tranny though...

[wilbo666]

I ran a steel plate W55 for almost a year behind my 1JZ-GTE (suspect a little more power than a 2JZ-GE) without drama. There isn't and inherent weakness with the box IMHO. I was / am running a twin plate clutch as well...

And as Norbie said, looking at a W55 compared to a W58 there is sweet FA difference besides ratios.

A comparison I did....
http://everest.fit.qut.edu.au/~n4150...14-08-2005.pdf

Cheers
Wilbo

[grahamd]

Urantia - IS200 with 1JZ is still very nimble. Was a bag of sh** but just needed a shockie change to cure the problems. Fitted Koni adjustables and it is light and really throws around again.

[urantia]

About time you showed up on the new toymods graham.
;p

Thanx for the info!
Hmm this off subject, but graham do you know the weight difference from the original 1g to the 1jz vvti you installed? (was contemplating the 1uz, but the clearances are too close for comfort)

[grahamd]

Just don't spend as much time on Forums as I used to. Usually check them every couple of weeks.

Weight difference - about 30-35kg plus any change of gearbox - Getrag box alone was 35kg heavier. Sat the front down by exactly 10mm so if you can find the Lexus spring rates you could work it out.

Back on topic - what options are there for IS300 diff ratios. I want to replace my IS200 diff with something a little stronger. Have a new motor sitting in the garage to drop in one day but need to upgrade the diff first.

[Mr Revhead]

http://trdparts.jp/english/parts_lsd_mechanical.html

have a look at the TRD part number, then cross reference it to other models for other cars with the same diff