Shifftting From Park To Drive Or Revers Problem

[amicore]

I have 91 LS400 with 160000. So far never shifting problem. Lately during shifting from Park to Drive or Reverse hole car “shakes”, “jerks”, “jumps” a quite bit. Soon in gear no problem to drive. When driving auto shifting up and down normally. Does not matter if cold or worm, same think. Thank you for any advice.

[qha_vn]

when you stop your car, try moving shifter from D to N, engage parking brake, then move shifter from N to P. later, see if your car still jerks when moving out of P

[eatingupblacktop]

Welcome to the LOC!

Sounds like the shift position switch, shift lock solenoid, or brake pedal stop light switch could be acting up. Try using the shift lock override button while your moving the lever into gear to see if shifting becomes smoother.

[don corleone]

check the throttle cable. another common symptom is that when you apply the cruise control the gas pedal will auto adjust to the correct position. here is a pdf about it you can also search for more information.

transmission_servicing_at.pdf

[amcdonal86]

I test drove 2 '97 LS400s when I picked the one I have now. Both did the exact same thing when they were cold, and mine continues to do it when cold. I find it to be a non-issue. I think it's caused by the high idle in cold weather startups. When you kick it into gear, the car has a bit of torque at 1400rpm or so, and it lunges a little bit. Once the idle is down to the normal 500-700 it doesn't do it anymore. Strangely, the 2000 LS400 I test drove did not do this when cold.

[eatingupblacktop]

I test drove 2 '97 LS400s when I picked the one I have now. Both did the exact same thing when they were cold, and mine continues to do it when cold. I find it to be a non-issue. I think it's caused by the high idle in cold weather startups. When you kick it into gear, the car has a bit of torque at 1400rpm or so, and it lunges a little bit. Once the idle is down to the normal 500-700 it doesn't do it anymore. Strangely, the 2000 LS400 I test drove did not do this when cold.

Amicore has mentioned his prob ocurrs whether the car is cold or warm and no mention of a high idle.

[amicore]

Amicore has mentioned his prob ocurrs whether the car is cold or warm and no mention of a high idle.

Thanks, car lately has high idle when cold about 1100-1200 rpm, when worm ( takes some times 15 minutes driving) around 700 rpm and does the same thing cold or worm or maybe a little less jerking at worm I don’t remember before so high idle. After mechanic changed my drive belt I notice higher rpm. I think I should turn down a throttle position sensor like other cars. I don’t now if Lexus has any TPS? I tested GHA--.. advice to when Parking; shift first to N, applying park brake and shift to P. Does the same.

[amicore]

Welcome to the LOC!

Sounds like the shift position switch, shift lock solenoid, or brake pedal stop light switch could be acting up. Try using the shift lock override button while your moving the lever into gear to see if shifting becomes smoother.

Thanks for Welcome.

I did try Shift lock OD button on end off. Brake stop switch looks like no problem there, checked play on the pedal , light goes on and off fine.

[eatingupblacktop]

Thanks, car lately has high idle when cold about 1100-1200 rpm, when worm ( takes some times 15 minutes driving) around 700 rpm and does the same thing cold or worm or maybe a little less jerking at worm I don't remember before so high idle. After mechanic changed my drive belt I notice higher rpm. I think I should turn down a throttle position sensor like other cars. I don't now if Lexus has any TPS? I tested GHA--.. advice to when Parking; shift first to N, applying park brake and shift to P. Does the same.

As AMC mentions, higher idle at startup in cold temps is normal and experiencing some torque/snap when shifting into gear during high idle is normal. If your idle levels off at around 650-700, there's no need to make any adjustments. Don't know which belt you're refering to, but a subsequent higher idle is prob coincidental with the cold weather. Hard to gage what you're experiencing by your description. If you think you still have a prob after the car warms up to operating temps, take it for an assessment.

[steve2006]

Hi,

The transmissions do tend to "bump" a little bit when going into drive especially when the engine is cold.

They also go into 2nd gear then 1st when drive is selected to help with shift shock.

If you haven't already it may be an idea to check the fluid level and the colour of the fluid ( should be a dark cherry red) also smell the fluid on the dipstick, if it smells burnt change it. Do a transmission fluid flush and refill with Toyota type IV fluid.

Another possible cause is worn engine or transmission mountings as they do fail.