Lock Out Solenoid in Transmission

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Lock Out Solenoid in Transmission[ALL/1998] posted by wayne on
Saturday, 7 June 1997, at 1:15 p.m.

Does anyone out there know what function the Lock Out Solenoid performs in the transmission of 1992 Volvo 960 Sedans. Volvo thinks thats what is causing me the failure to come down out of the high gear when driving slow around town from stop sign to stop sign. The car wants to stay in the upper gear as I slow to a stop which makes the engine want to stall out because its at such a low rpm then at the very last minute before it stalls out it thrashes hard into first gear. I am puzzled.

Thanks Wayne

Re: Lock Out Solenoid in Transmission[ALL/1998] posted by abe crombie on
Saturday, 7 June 1997, at 1:44 p.m.

There are four solenoids in that gearbox. Two of which are called S1 and S2 and they control which gear the trans is in by applying fluid pressure to other control valves in the valve body. There is another valve used to regulate fluid pressure that is applied to clutches and brakes that are used for changing between the gears. the fluid pressure is increased for hard throttle shifts and lessened for light throttle shifts. The last one is the locking torque converter solenoid that controls whether the converter clutch (internal part of the torque converter used to override the normal fluid coupling link between engine and input shaft to gearbox to improve fuel milage and decrease ATF temp) is engaged or not. Normally the locking solenoid (SL in VOLVO terminology) is only applied in 3rd and 4th gears. If SL were sticking it is conceivable that you could have symptoms like those you describe.

Re: Lock Out Solenoid in Transmission[ALL/1998] posted by Wayne Berryment on
Saturday, 7 June 1997, at 3:19 p.m.

Thanks for taking your time Abe to describe this to me. I like what you had to say because I am encouraged that the problem may be with this solenoid. A light kinda went off in my head when you touched on the ATF temperature. This problem doesnt start occuring until the car has been driven for say 10 to 15 minutes ( i.e. ATF fluid has been brought up to operating temperature ). The car is in 3rd gear when I begin to slow down to a stop and I can overcome the problem because I feel the car beginning to lug down ( i.e. wanting to stall ) and I throw it manually into neutral and this seems to kick it out of the mode its in when it wants to stall.

I'm going to give my Dealer the ball on this one and hope they fix it. I know one thing its not a cheap repair job! I'm almost wanting to try this repair myself but I haven't been able to find a real detailed 960 Repair Manual at my local bookstore.

Thanks Again for the comments, Wayne

Re: Lock Out Solenoid in Transmission[ALL/1998] posted by Mark Klein on
Tuesday, 10 June 1997, at 8:09 p.m.

when Abe said ATF temp, he meant the lock up clutch in the convertor locks up to prevent abnormal temp ranges due to convertor slippage. If the convertor doesn't lock up, it can overheat the fluid. With no recommended service interval for the fluid, Volvo wants to do as much as possible to prolong the life of the fluid. Still sounds like the SL solenoid acting up though.

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