Been checking the net for it and looking at a few vendors but cant seem to find one. Does anyone know where to get a new or rebuilt one? Most places i find that sell jz tc are high performance units which are very expensive.
If you mean you're building for 600hp or something in that area with a big single then yes, you're going to have issues with a stock A340E or A341 automatic transmission. Having it beefed up at an auto trans specialist like Level Ten might be an option if they work on those models but if you're a fan of manuals over automatics I'd definitely say the R154 is the obvious choice if any transmission work is to be done. I do believe some Supra guys have strengthened their automatics but there is still probably a horsepower limit even there.
R154's also need some strengthening out of the box to reliably take the 750whp they're supposedly rated for (and no one has ever mentioned what torque level that equates to in a JZ since it's torque figures that matter most when rating a transmission's maximum power threshold).
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 | USDM 2JZGTE in progress