[red68chevL]

Can you do this?

I recently upgraded to a 700R4 and am using the B&M shift-lockup controller. I have it set to lock around 48MPH. But the kit instructions say it will lock in 2nd, 3rd, or 4th. So they don't mean it will shift while lockedup , do they? Will this damage the tranny?

where do you guys have the lock up speed set at? It's a driver, not a track car.

 

[chuckd71]

Mine isn't running yet but I'm using one of these and am interested in knowing this as well.

 

[slingslingbinks]

Hey Scott As long as the trans has made the 1-2 shift, you can lock it up and it will shift into the gear's while it's locked up. While in lock up the shift's will be have a different feel and a little harsher than in converter mode, but it will shift. the speed of 48 m.p.h. for lockup sound's good. Just for the heck of it, What model of 700r4 ya got? Does it have the converter shift valve train in the valve body or is it casted over for an ecm controled lock-up? C-ya Scott

 

[rodderscorner]

yes you can shift while locked up. but the lock up wasn't built for that, and it will fail.(slip) and you'll get a nice chatter

 

[Philip]

My 82 Corvette (first year for the 700R4) was designed to lock up in all gears but 1st. I am unsure if it shifted while locked, but I think it did.

 

[Winston Wolf]

I have one of these in my car.

Once it gets to the lock speed, it will stay locked until you get under the unlock speed, about 5 mph below the lock speed setting. It doesn't care what gear your transmission is in or if it kicks down or you shift it or whatever.

One thing to note. I found that the output voltage wasn't high enough to keep the solenoid engaged. I had 2 boxes that went bad, and would only put out 6 volts. I finally ended up having to feed the output to a small relay and use 12 volts from before the brain box as the relay output.

When I'm driving, and need to accelerate at a moderate level from a low cruise RPM, I like to (read need to) unlock the converter and allow the engine to rev up, not lug. For this, I installed an adjustable vaccum switch. Mine is set at 7" hg, so once I press the pedal far enough, (but not enough to kick down to 3rd) it will unlock. Once I let up on the gas, it will relock. I couldn't get by with just a vacuum switch though, or it would chatter in and out if I was just at that 7", or it would relock immediately when you let off the pedal. To solve this problem, I installed a vacuum delay valve before the adjustable switch. This will cause a several second delay once you re-establish your cruise level and stop it from kicking in and out.

I found this to be the best way to make it work like I felt it should. With the vacuum switch, it makes sure that I'm never locked under heavy throttle, which makes the car drive much nicer. I lock mine at 55 MPH, and it unlocks at 50 ish. I just wanted the B&M to stop things from locking until I got up to highway speeds. I run a deep gear (4.56) so I'm in 4th very quickly buy never want it locked under 2000 RPMs (which is 55mph for me).

I also have a switch I flip that bypasses all this stuff and allows me to lock it with a seperate switch in any gear. Then, when I'm draging, I hit the lockup in 3rd gear and let the engine work down the top of the track. It does make it faster in the 1/4 mile. I have a heavy duty clutch converter designed to do this however.