nevermore

Hey guys, I have a 1996 ls400 and I’m having issues with shifting. When I shift the car out of park to drive, or to reverse, It jumps harshly. It does not happen when shifting into neutral and I don’t have any issues while driving. The ECU is not the issue as I had it rebuilt just a couple months ago. Could it be shift solenoids? I’m not sure but any advise would help a lot, Thank you!

deanshark

Sounds like motor mounts are bad, or maybe just the tranny mount. When you put the car in gear it gives the engine alot of torque so the engine will try to move, or jump.
Do you have vibration on the shift lever? == tranny mount
Whole vehicle shake when engine running, especially in gear?== motor mounts

nevermore

There’s no vibration when the engine is running, it runs extremely smooth while idle and while driving, which leads me to think it’s not mounts. I’ll check to see if the engine jumps when I shift though. Thank you

as99east

Based on everything I’ve read online it feels like your first stop should be the tranny mount. Do you know how many miles you have on your tranny mount?

bradland

3rd vote for trans mount 👍

400fanboy

You don't know how bad they are until you replace it. Rev the engine in neutral. There should be no vibration, the allowable tolerance here is zero. If you fell anything other than the engine torquing the body, motor mounts are shot. Vibrations should start at 2000 and get worse the faster you spin the motor. When driving, vibration from motor mounts isn't terribly noticeable. I thought my car was perfectly smooth while driving when I had two cracked motor mounts. turns out I didn't know what smooth was. Perspective is everything.

When you come to a stop at a stop sign, does the car clunk and take a second to transmit the power after the revs jump? Is there audible clunks to these feelings you're having? If so, suggests transmission mount just like everyone else. If not, we'd need more diagnostic information.

paulo57509

Does it do this all the time or just after a cold start? As in cold engine running at high idle?

timmy0tool

iTrader: (7)

trans mount , but also when was the last time you changed your ATF?

Losiracer2

If the mounts are original, they're no longer good anymore. Rubber doesn't last 20+ years, I guarantee you they're either torn, sagged or collapsed or all three. Replace them and you'll be amazed at how much NVH reduction they actually do. Only use OEM Lexus mounts, don't cheap out, they're not created equal.