Question : 4T60 and the missing 1st gear shifter

[95SleeperAcheiva]

i did a little research and need the tranny guy's to speak on this one.

the valve body on an achieva doesn't have a 1 st gear in the selector.
the valve body on a grand prix, does, i think, i haven't pulled the shift cable off yet and counted the clicks.

I looked up the valvebodies in gm catalog and the part numbers are differant. makes sense, differant VB's. so i looked into the cases, thinking maybe, if i swap the valve bodies, i can then get 1st gear? the cases part number seem to match. do they? can i just swap the vb's, the shifter and by-pass the comp shifting as discussed in an earlier thread?

which brings me to the next question, if i do the obd1 swap (from the '95 1.5) does ben even need to worry about his code in his chip not working for the tranny? because, I don't need lock-up, and it'll be full manual shifting anyway. right?

[robertisaar]

well i can help with the electrical side: i imagine as long as the chip thinks its a manual tranny car, you shouldn't have an issue there...

the shift light might come on, if its been wired in...

but it sounds like you're going in the right direction...

[IsaacHayes]

You still need the auto code there, as you don't want it stalling/etc when coming to a stop or idling. So in that regards leave the auto code, but no need to tweak it other than change the rev limiter for drive if you wish.

Auto/manual idle's different RPMs and other things. Best to leave it there so it at least can keep the motor idling right when gears change/etc.

You can still wire up a switch to lock the converter for hwy driving. That other guy did.

[95SleeperAcheiva]

don't need lock up, only highway time she'll see is when she's being towed to the track. but i see your point.

[pocket-rocket]

I'm not sure how much different the Acheiva wiring is vs the w-body wiring, but I know when I did my 5 speed swap, the TCC output should have been run to the shift light to make it functional. Besides, manual code has provisions in it to keep it from stalling when you come to a stop. If I roll down a hill at 5mph (not sure what the minimum speed is), my rpms raise slightly if it isn't in gear or I have the clutch in. Even my truck does it, and it's not even a GM. If you left the auto code in, the computer would freak when a) it can't find the auto trans components hooked to it, and b) gears are changing when they aren't supposed to because it's being controlled manually and not listening to the ECM. At least that's what I would think anyways.

[robertisaar]

from what i've been reading 95sleeperacheiva is going to try and run a 1227730 ECM, which means electronic tranny control is no longer an issue. whether its set as a manual or auto shouldn't matter as much now. but thats what i tried to say before about running it as a manual. isaac thinks differently, but i guess we'll see soon enough if it matters with a ECM that could care less about electronic shift solenoids

[pocket-rocket]

Ah, I am not really into tuning/ECM #'s so I didn't realize it didn't have trans control. Most of the pushrod guys have kept Ben to busy to teach me to tune, and my car needs some work before I feel I can safely drive it down the road (bad rear struts, causing tire bounce when braking over uneven surfaces, bald tires and misaligned rear end causing the rear to walk around/hydroplane in the wet).