1994 LS400 won't shift automatically

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Aug 16, 2018 | 01:57 PM

Roayltee

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From: Nebraska

1994 LS400 won't shift automatically

Hello,
I have a 1994 LS400. Recently the car has not been shifting gears when car has been running for 20-30 minutes. Runs fine until driven for 30 minutes. My check engine lights comes and I hear a loud burst of air when it starts to act up. There car will not accelerate. I can move to 1st gear from a standstill and car will accelerate normally. I have to shift from 1st, to 2nd and D and car will move but still can't accelerate at higher speeds. Also, when idle, I can hear a low humming/rumbling. My lexus dealer said that it was the MAF sensor, clogged catalytic convertors(drv and pass), and failed O2 sensors(both drv and pass, before and after). I've replaced all these parts but still having issue. Also, i just noticed a fairly larger puddle of tranny fluid under car after it sat for 3 months. Has anyone ever experienced this or know maybe what the problem is?

Aug 16, 2018 | 04:54 PM

RA40

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Ouch. Dealers love to suggest replacing the O2 then go onto plugged cats replace routines. Those cats are $$ for them. That's done so next is getting the car to shift right. Relative to the parked car, where was the tranny fluid puddle?

This is a good read for supplemental issues.
https://www.clublexus.com/forums/ls-...capacitor.html

Aug 16, 2018 | 06:44 PM

Roayltee

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Luckily I have good friend that's a mechanic. I just had to buy the parts online and he put them for a small price. The leak looked to be falling from the front of car on driver side, near rear of the engine.

Aug 16, 2018 | 07:14 PM

RA40

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WIll have to get under the car and find the exact location, some thoughts are the dipstick O-ring or the pan seal. At what level is the fluid now?

Aug 16, 2018 | 07:26 PM

Roayltee

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I can't say accurately because the engine is cold now. When I checked it early though, it appear somewhat low. Maybe a quart low. I've been having this problem for awhile now. I had the fluid changed when I first noticed the problem and it still was happening. So I'm not sure if its a fluid level issue.

Aug 16, 2018 | 08:51 PM

RA40

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IN part so getting the proper fluid level is going to help lots. We've had a variety of good discussions on the shift solenoids and the related symptoms. Those past threads will be good reading.

Aug 17, 2018 | 08:03 AM

Roayltee

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Okay. Thank RA40! I will search for the threads that you are referring to. The thread that you sent me in your first response talks about capacitors. I found it a little useful. I will continue to search but if you have any links you can send me, please do. Thanks for all your help.