you could also go the R154 from the mk3. You still need the bell housing and you'll need to extend the shifter as well. Also remember you'll need a new set of pedals as well if you go 5 speed, i believe the brake and clutch
there is no 1jzgte w58, the mk3 in the US had a 7mge and a w58 or a 7mgte and a r154. In japan the 1jz's cam with r154's, maybe there is a non turbo version with a w58 but I have not seen one anywhere really. if you get one from a w58 mk3you will also need the JZ bellhousing and the shifter will need to be extended to fit in a mk4/SC300/sc400.
If you get a w58 from a mk4 or sc300, then it will have the right bellhousing and the shifter wont need modifications and will be more straight forward of a swap.
Ok I got another Question, Do I need to get a new flywheel when doing the swap? Can I use my 2JZ Auto Flywheel with the W58?
For a W58 you'll need a W58 JZ flywheel which is available in the USA.
For an R154 you'll need a JZ R154 flywheel which is kind of available but only from importers. Cost is so-so. There are aftermarket lightweight R154 flywheels available but the best option is still an OEM JDM R154 flywheel. Or maybe a JUN chromoly.
What do you plan to do with the car? Just swap to manual and do suspension work or go turbo? If the latter, look into an R154 regardless of which version. MKIII R154's are fine to use but will need a JZ bell housing, Soarer shifter extension (or extended MKIII housing) and either a Driftmotion trans mount adapter... or a modified SC crossmember to fit the MKIII trans mount... or an SC W58 trans mount connected to only two of the four mounting holes on the trans tail housing (I don't recommend), OR... you could do what I did and find a 1982-85 Celica W58 transmission crossmember which fits the MKIII mount and have that cut and welded to have it extended 1" on one side. Unfortunately there is no elegant OEM solution to the rubber trans mount and crossmember when using an MKIII R154 on an SC/MKIV but don't let that deter you.
You also might as well get the correct transmission tunnel per type of manual transmission so that you have the correct opening location: SC300 92-94 early tunnel for W58/R154 with metal extension housings & Supra MKIV 6-speed tunnel for all "tripod" style W58/R154/V160 transmissions. Plenty of people cut their tunnels but it helps more if you have a tripod manual transmission.
And as has been mentioned above, the MKIII Supra and earlier W58's are indeed weaker than the ones found in the SC300 and MKIV Supra due to the later ones having a steel intermediate plate.
1993 SC300 5-speed NA | Built R154 | Gixxer_Drew Susp. 600/325 | TT: brakes FR, rims, rear sway, seats | Koyo rad | 4.272 TT Torsen LSD | 2JZGTE in progress
i'm planning to do this as well. a buddy of mine has a tripod w58 he had in his sc400 but he blew 2nd gear, he only wants 275 for it and i almost bought it last week. i found rebuild kits on ebay for like 140 for a complete overhaul of the tranny. besides pedals, shifter, dash pieces, and the transmission itself, i'm guessing you need a different ECU as well and i heard the powersteering, and a few other luxuries are lost then? is that true?
I would get a working w58 it will cost less than rebuilding one unless you know how to do it yourself, even then its risky when a working one costs only a few hundred more than that. parts are $140 but the labor will be ridiculous if you haven't factored that in already. maybe if he was giving it away.
you will need the trans, clutch pedal, master/slave cylinder, shifter, shifter trim, automatic ecu will work fine with manuals it just won't be perfect. I am running my 5spd on an auto ecu right now, it just cannot be done the other way around (cant run auto on manual ecu).
powersteering is not affected at all, no other luxuries are lost, cruise control can't remember but not important whatsoever.
you can also get a 5spd brake pedal as they are smaller to accomodate the clutch pedal, or some just saw a portion of the original one off to match.