can u disable lockup on a 350c

[Bonnewagon]

There should be 2 wires in the harness that is on the connector located on the side of the transmission, near the gear selector shaft. One is +12 volts power, one is ground. The ground signal comes from the computer. There are several switches that need to be closed for the wire to be grounded by the computer. One is inside the transmission so it will only ground in high gear. One is at the brake pedal so it dissengages when the brake is applied. One is on the MAP sensor so it disengages when you give it enough gas to drop manifold vacuum sharply. One is on the temperature sender so it only works when the car is at operating temp. They are variations, but most use +12 volts to the brake switch, and the high gear switch is in that line. the rest are fed to the computer so it makes the call when to engage.
By cutting the wires at the transmission, I ran a fused +12 volts to the brake switch and - ground to the other. The ground you can run to your toggle switch and have total control over when it engages, except for the high gear switch inside. I left the brake switch for the reason that when I wanted to accellerate all I had to do was tap the brake lightly with my left foot and it would dissengage.

 

[Possumz]

I removed the plug on the trans today before my trip back up from North Carolina today. I had no issues with the trans and was ticked pink :lol: that I got 17.5 mpg average for my 450 mile trip i made this week. The plug had 4 wires. Looked like 2 black and 2 green i think. One of the black wires looked pretty bad as it was bar about an inch up from the connector and the fact that the plug had oil in it as well. Any pics of where you spliced in. I want to hook up the same way you did. Thanks for all your help.

 

[Bonnewagon]

I'm not familiar with the 4 wire set up, mine is an 83' Pontiac and only had 2 wires, a purple and a tan/black stripe. You would need to look in the Chevy book to see what is what, pulling the pan would explain it but that's a chore. Sorry, no pics, that trans was donated to a friend's enduro car. 1 wire should be hot from the brake switch, mine was purple, and 1 should be ground to the computer, mine was tan/black. I just ran the ground to the toggle on the dash and then grounded it to the metal dash bracket. The hot to the brake switch was pink/black stripe.

 

[Possumz]

I will get a pic tomorrow after I clean the wires off.

 

[axisg]

Hmm, I recall a 2 wire plug going into mine ( when I had the 350c ).

My preference for wiring up the toggle switch is to bypass the brake light assembly and factory wiring and just to run a clean new line 12v+ acc (so it only gets power when the ignition is on ).

From the fuse panel get the 12v+ acc power wire and at the same time grab the 12v neg from the ground on the firewall next to the fuse panel or one of the bolts that holds the gas pedal mounted to the firewall ( I like using an old lamp wire then crimping and soldering the ends so the + pos and neg run together instead of taping 2 wires together ) Wire the 12v + thru an in-line fuse; and then the toggle switch ( mounted somwhere within easy arms reach ); then to the trans ( rather than toggling the 12v neg back thru the factory wiring which may be why it's not locking up in the first place ). Then you can run your wire thru a grommet in the firewall and attach it to the plug wires on the trans with solder and heat shrink ( cutting back the old factory wires and taping them off in case you ever figure out whats wrong or want to switch back ).

You just need to figure out which trans you have and the pinout locations as I do not recall the 350c trans having 4 wires. Should only cost about $5 in materials and an hour or so of your time. I still use the same toggle switch with my 200r4 trans and it's just habit to flick it on when I get on the highway ( I got one with a bright LED light that illuminates when its on ) and flick it off when getting off.

 

[tc1959]

You could just fix it by replacing the governor pressure switch to a higher value one, from a 35 to 40 lb to a 55 or 60Lb this will stop it tcc from bopping in and out at lower speeds to a higher highway speed.

 

[pontiacgp]

here's a picture of the 350 I found

 

[Possumz]

Is it possible that I have the th250c or something else behind this 305. I swear the pan looks like my other two cars with th350. Anyone with a wire diagram for a 1983 Monte with the 305 out there. 🙂

 

[stomis]

Is it possible that I have the th250c or something else behind this 305. I swear the pan looks like my other two cars with th350. Anyone with a wire diagram for a 1983 Monte with the 305 out there. 🙂

I always thought that my old lady 307 Regal had a th200 or 250 what ever it is behind it... Was an 86 so I think it could be a possibility.

 

[pontiacgp]

if you arn't sure if it's a 250 or 350 cause the two of them are identical there is one difference