To start off with, I have a 2003 Is300 with a swift racing turbo kit. Dynoed using the AEM FIC. Transmission, has toyomoto shift kit. My problem is, when under boost the transmission just will not shift into the next gear unless you completely let off the throttle and then hit it again. It will just rise in RPMS and just sound like its redlining. Under normal driving operations, the car shifts great. I have searched and have only come up with one solution, full standalone. That wont happen at this time, because of the cash flow. If anyone out there has any solution or even something that might help even a little, it will be greatly appreciated.

Thak You,
Jason

 

I run full standalone i doubt thats teh issue. How much hp are you making? Sounds like your 3rd gear sprag (or other gear) is on its way out. My car did the exact same thing driving normal was fine occasianlly under boost it would get stuck until i let off until it got so worn out it would hardly shift even driving normal. Take it easy on it dont do any low gear pulls it will wear out alot faster that way.
Also try posting over on my.is lots of people there who really know there stuff.

Where in tx are you?

 

Im making 330 rwhp. I kinda understand where your coming from on this. Do you think a built tranny would solve this problem? Texas City, about thirty miles from Houston

 

Time for a swap! Stick ftw!! It does sound like ur tranny though. Good thing I don't have an auto haha

 

Personally i would rather have a auto for the racing i do. Does your current tranny have any upgrades? Under 400 i wouldnt think you would have that prob usually when you get above 450 is when you start to have probs. But ya upgrading the 3rd gear sprag is prolly what you need its the most common gear to go but it could be one of your other gears as well. A buddy of mine here in dfw has fixed mine and has upgraded sprags if your ever out this way haha.