I have a 92 SC300 5 speed and am having trouble with the transmission. It pops out of 4 gear about 25% of the time. After talking to a couple of reliable shops, I am faced with repairing this trans or replacing with a used one. My question is, will a Supra 5 or 6 speed fit the SC without any modifications? There seem to be more Supra 5 speeds than SC 5 speeds available.

TIA,
David.

 

It is the same tranny, the W58. But yes, a 6spd will also bolt right in, althought you will need a custom driveshaft, gears will be a litte short (6spd normally has 3.13 rear end versus the 4.10), master cylinder may need to be upgraded depending on clutch, need a 6spd clutch, etc

 

with a 6spd on a 92 you also need to cut out the tranny tunnel to allow it to fit...and make a custom plate

 

I think Clint's right...I think Jeff's right...they should get in a fistfight! haha jk

 

Damn Clint....good to know you're still breathin' guy!

How's everything?

Marken, aka Lexlyf
CMO, Swift Racing Technologies
www.swiftracing.com

 

clint is right about the drive shaft and need for upgrading gears......and if you have a 5spd sc300 the master cylinder will do fine with the 6spd tranny..you just need the slave cylinder for a 6spd.....i have an upgraded RPS clutch on my 5spd mastercylinder for a while now and its doin fine...Jeff

ps...how the hell are ya clint...the man...the myth....the legend....

 

Our 92 sc300 mit five speed just had a new clutch; feels good. Only thing is that we still feel the gears when shifting; ie, like the syncros are not working that well. This does not inspire confidence in high speed driving when shifting in awkward situations is required; makes one want to double clutch all the time.

Is this just a crappy transmission or is mine getting a little worn with 96k on it? How much does a rebuild of a stock tranny run? Estimate range?

How difficult is putting a six speed tranny in? Has anyone published detailed instructions?

Regards,

Carl

 

Sounds like the recent work may have included the wrong,or insufficient fluid back into your gearbox,or that the clutch disc is hanging up a bit.

 

We used Redline synthetic for the gearbox and rear end; Mobil 1 in the engine. The clutch definitely works better now but the gearbox changing feels pretty much the way it did prior to changing the clutch.

Perhaps I am expecting too much from this car; I am used to 911 manual gearboxes which feel more robust. Only other jap cars I've owned are low end toyotas and hondas and the second to third syncros are a joke in most of those.

I'll take it back to the mechanic and ask him about it. I suspect I'll be double clutching a lot.

Carl

 

I use a little(1/2 to 1 quart)of GM "Synchromesh Fluid" in my cars,and it has helped more than anything else to get rid of the little "snag" when shifting.Before that I'd tried just the Redline MTL.
This is in cars with Getrag transmissions also.

 

Thanks for the tip; we'll try it. It appears that the mechanic screwed up the clutch install or the new clutch is bad; am getting a lot of chattering....I have to release the clutch and just above idle to get smooth engagment. IE...cannot slip the clutch as tremendous chatter sets in.

Any observations?

Carl

 

If you're dealing with organic (OEM or Lexus) clutch disk, chatter is NOT normal. Either they did a crappy job of turning the flywheel, or similar. I would suggest new flywheel, not resurfaced one. On an upgraded carbon puck disk or sprung carbon disk, chatter is normal and an unfortunate necessity in trying to hold so much power on a small diameter disc.

 

Mechanic is saying a new flywheel; now we see if he tries to charge me for the labour to do the job that should've been done right the first time.

Thanks for the information.

Regards,

Carl