cabinetman

I have a '97 Blazer LT 4x4. I recently posted a "Check Engine Soon" light, and it didn't read a code. Well I went to another shop and it turned up a #740, which I looked up and it says "Torque Converter Clutch Circuit Malfunction". What the trans is doing is not starting out in first, and ultimately at speed, not shifting in 4th (high). Moving the lever to 1st, does not do anything. I think it's starting out in 2nd. Anyway that's the trans problem. Does it need a rebuild?

Next is the ignition lock. Sometimes the key won't unlock to go to start. And now the problem is that I can't lock the key in position to get the key out of the lock. About a year ago, turning the key didn't turn the ignition on - no dash lights either. The dealer replaced some switch in the steering column.

Thanks for any help. I'm desperate!!

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old_master

If only P0740 is present, the VCM will not allow the transmission to shift into 4th gear. If the VCM detects an open or short to ground in the TCC (Torque Converter Clutch) solenoid valve circuit, it will set the code. It shouldn't affect downshifting to first gear though. Other than checking the CLSTR fuse 11 (10 amp) and the wiring to the transmission, a scan tool will be needed to diagnose the problem. It is possible that the valve is stuck, in which case it would feel as though you're starting out in 2nd gear, and you wouldn't feel the transmission shift into 4th because the torque converter is already locked.

goalkprrr

my 97 does the same thing what was the fix my codes were 740 and 1860 feels like it is stuck in drive starting from dead stop so you manually shift it but it will not manually go into first starts out in second after awhile service engine light will reset itself and runs fine for a while then out of nowhere ses light will come on and same thing any ideas dealer says maybe vcm module

old_master

goalkprrr,

It would be best if you start a new thread with your problem. That will keep confussion to a minimum. Thanks.

cabinetman

I found out what the ignition key problem was. There is a sender in the shifter that sends a signal to the ignition that the vehicle is in drive and wont let the key turn to "lock". FIX: Remove receiver in steering column. Next the lock was worn and the old (maybe replacement key) wasn't cut absolutely perfect. FIX: Change the ignition lock.

Now for the trannny problem. When cold (sitting overnight) the first 1/4 mile or until it stops the first time, the tranny will up shift. After that it's in 3rd gear. Code was a 740. Is there an easy fix???

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