Torque Converter Lockup too early?
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Joined: Apr 2005
Posts: 101
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From: Perth West Australia
Car: 86 Z28
Engine: '90 350 TPI
Transmission: T700
Torque Converter Lockup too early?
Hi all. I recently purchased an 86 Z28 here in Perth, Australia and am having problems with the trans. It feels like the torque converter is locking in when i hit low throttle in 2nd gear. Has anyone else had this problem and if so what needs to be done? Thanks
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From: Moorestown, NJ
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Might just be the way the computer is set up. Its set up to lock early and if you have 2.73s, itll easily lock up in second gear. As long as it unlocks during 4->3 shifts and when you punch it the TCC function is probably ok.
Joined: Feb 2001
Posts: 8,494
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From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
I had a similar problem. I'll spare you the how and why, and jump right to my solution.
I wired a manual switch up to the brake switch. That fools the computer into thinking the brakes are on and it won't lock the converter. With the flip of a switch I can go back to "normal" mode for highway driving, but around town I leave it off.
I had 2.77 gears and a 2200 stall converter. When I swapped in a 3.27 rear axle it was no longer a problem.
I wired a manual switch up to the brake switch. That fools the computer into thinking the brakes are on and it won't lock the converter. With the flip of a switch I can go back to "normal" mode for highway driving, but around town I leave it off.
I had 2.77 gears and a 2200 stall converter. When I swapped in a 3.27 rear axle it was no longer a problem.
Thread Starter
Member

Joined: Apr 2005
Posts: 101
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From: Perth West Australia
Car: 86 Z28
Engine: '90 350 TPI
Transmission: T700
thanks for the info guys. the TC unlocks when you do put your foot down but when it locks up so early (like in 2nd) it causes the car to shudder a bit. also, because its locking up so early, it is constantly unlocking again when driving in the city (like when you slow down to take a corner) and ive heard this can damage the trans. there isnt any way to adjust the computer is there??
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Joined: Feb 2000
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From: Schererville , IN
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
Hit the DIY-PROM board(my sig). Lots of info on tuning and reowrking the annoying factory TCC setup :-)
later
Jeremy
later
Jeremy
Thread Starter
Member

Joined: Apr 2005
Posts: 101
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From: Perth West Australia
Car: 86 Z28
Engine: '90 350 TPI
Transmission: T700
i have decided to go with Abubaca's idea of a manual switch. anyone know where i can get a wiring diagram and how do i make it so the brake lights wont come on when the switch is on?
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Joined: Feb 2001
Posts: 8,494
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From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
OK, don't quote me on this, but I "think" it was a pink wire. I'll have to go out and stick my head under the dash tomorrow. Anyhow, I just bought a switch from autozone and wired it inline with the appropriate wire.
Maybe it was purple?
....lemme see if I can't do a search and find out.
Maybe it was purple?
....lemme see if I can't do a search and find out.
Joined: Feb 2001
Posts: 8,494
Likes: 411
From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Hah! It was both pink (power to switch) AND purple (switch to tranny).
Here's the thread. About halfway down, IrocZZ3 suggests the method that I used.
https://www.thirdgen.org/techbb2/sho...hreadid=265783
Here's the thread. About halfway down, IrocZZ3 suggests the method that I used.
https://www.thirdgen.org/techbb2/sho...hreadid=265783
Thread Starter
Member

Joined: Apr 2005
Posts: 101
Likes: 0
From: Perth West Australia
Car: 86 Z28
Engine: '90 350 TPI
Transmission: T700
had a mate install the switch today.... took about 10 minutes and car runs smooth like it should now. thanks for all the help guys!
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From: B'ville, WV
Car: 2002 Formula Firebird
Engine: LS1
Transmission: 4l60e
Axle/Gears: 3.23
Hey, Abubaca. How did it run with the stall and 2.77's?
I haeve 2.73s now. I plan on upgrading gears later but my front seal is leaking so I need to change that now. No better time to throw a stall in it either.
I want a 2400. But I'm afraid the trans will get to hot. Think it would be ok with my cooler and if I put a lockup switch on it.
I haeve 2.73s now. I plan on upgrading gears later but my front seal is leaking so I need to change that now. No better time to throw a stall in it either.
I want a 2400. But I'm afraid the trans will get to hot. Think it would be ok with my cooler and if I put a lockup switch on it.
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