200r4 shifting early

[Nitromad]

Hello, and thanks in advance for any help.

I have a 200r4 with good internals and is set up as a non- lockup. I have a PTC 3800 stall. And 3.73 gears in the rear (if that matters). The problem is it is shifting its self at 5500-5800 from 1st to 2nd even though I have it down in 1st on the selector. My engine doesn't start making power until about 4500 so it shifts WAY to early. It holds second just fine until 8k when I shift. I have tried adjusting the Throttle cable with minimal results. Please point me in the right direction.

Thanks, Jeremy

[Ridings Automatics]

Will upshift on its own even if the selsctor is in low 1 {or m1}. Depends on the valve body codes and spacer plate that your trans was built with. It seems like the performance cores {like brf or brq>> grandnational or the cz >> monte ss} seem to be more sensitive to the upshifting early than other calibrations. I've had pretty good suscess with the AA level core { cad 4.1} holding 1st thru 6500 rpm's.

[Nitromad]

Mine is a 84 Hurst/Olds Cutlass. Not sure if that is what you would consider a performance core. So what can I do?

[Ridings Automatics]

cores. It depends on what reverse/inttermediate boost valve the trans was built with {I install the largest OEM valve .296 in all my builds}. TCI sells a .400 rev/intt boost valve that should keep it in low 1 longer . The only other way i know to delete the 1-2 upshift in low 1 involves valve body casting mods along with mods to the 1-2 shift valve assembly {won't effect the regular upshifts}, but it's irreversable once done.