Has anyone had a Torque Converter fail in their LS400?

If so what symptoms did you experience?

I get a brief shudder when taking off/leaving from a stop and it almost seems to lag in acceleration for a second or two as well after hitting the gas. She shifts just fine and had fresh T-IV fluid and filter done in the last few thousand miles however the symptoms were present even before that.

 

what year is your LS400? mileage?

could be an ECU cap issue: https://www.clublexus.com/forums/ls-...capacitor.html

 

'94 with about 203k

ECU has been fixed in the past few years but living in hot and humid south florida does not help...

Car has sat for months at a time working on various things. I think these tires could be permanently flatspotted from sitting for months without moving as well so i guess thats a possible place to look. I also get a 3rd order tire vibration as the main vibration when using my NVH analyzer.

Maybe its more of a shimmy then a shudder? I may just start with the tires first

 

I don't have anything to contribute other than to suggest the easy things to check (motor and specifically transmission mount), but I'm going to imagine you're ontop of that already. Beyond that we've reached the limit of my knowledge.

I'm just commenting here because I wish I had your NVH analyzer lol.

 

Sounds like the old vetronics machine Toyota used to use, I think that thing was manufactured to sell tires. Doesn't sound like a converter to me, does it ever stall going into reverse?

 

Tires causing a shimmy\shudder from a dead stop doesn't seem likely to me. You gotta be going at a pretty good speed for tire issues to present themselves. You can't determine that at 7mph.

 

check your throttle cables for binding or loose connections, and see if lubricating them helps.

also to consider: i always had to recalibrate my foot when driving an LS since the throttle never seemed to react as quickly as i wanted it - deemed normal and per design.

driveline vibes: always start with the wheels/tires then i would next check the trans mount which is a common failure point that contributes to vibrations.

 

It is an app for Android/iOS called NVH. Nothing special really and who knows how accurate it is.

Nope, no stalling in reverse.

I agree, which is why I'm really at a loss here.

​​​​​​All new engine and trans mounts and I have had 2 different driveshafts in the vehicle with the same exact symptoms. Also replaced cv axles and diff with the same symptoms.

I'm not sure where to go from here. I really don't want to give up on her but it's honestly getting annoying at this point after 2 years. A Lexus that isn't smooth is very frustrating.

 

I have a 97 LS400 purchased when it was a year old. I still have it to this day & it still drives like a dream. After 20 years of driving (5 years ago), my torque converter started slipping at 225K miles just like yours even though I had religiously drained & filled the tranny at every 25K miles. Initially, I replaced the torque converter with a remanufactured one but it only lasted a little more than a year. Since my car is in great shape & I have it for so long so it has a sentimental value to me, I was thinking about swapping the entire tranny with a used one but these cars are 20+ years old so most likely, a used torque converter is also on its last leg & all of the tranny's rubber seals are rock hard by now so if I go that route, I'll run into the same issue all over again a few years down the road. Based on that assessment, I went ahead & had the tranny completely overhauled. I had also replaced the rear main seal while the tranny was out. It has been 4 years now & the tranny is still working flawlessly so I'm very happy with the decision I made.

Here's my recommendation: Take your car to a reputable local tranny shop & have it check out. Once confirmed & if you're on a budget, you can opt to replace just the torque converter & hope for the best. If you want to keep the car for a long time then you may want to cough up the money & have the tranny overhauled. If my memory serves me correctly, I paid about $750 for the torque converter's job & $1100 for the completed tranny overhauled. Good luck!

 

Thank you for sharing your experience. I have a reputable transmission shop that I trust and will have them look at it eventually.

Could you possible detail your symptoms when your torque converter went bad?

 

I started noticing the torque converter slipping whenever I backed out of my driveway & put it into Drive. It also happened at the traffic lights & during stop & go traffic. There's a distinct delay of a few seconds as the tranny was trying to find its gears. If I happened to step on the gas too much & since the torque converter was slipping, I could hear the engine rev'ed up then the car lurched & trembled a bit. Once it's in gears & rolling, it's drivable. I initially drained & filled the tranny with fresh Toyota Transmission Fluid Type T-IV, it helped for a little while, however the condition got worst to a point it became annoying & also a safety issue so I went with a completed tranny overhauled & I'm glad that I did.

 

Okay Thanks again.

My symptoms aren't quite the same so I may have to look elsewhere.

 

did you figure it out? I’ve got a 98 ls doing the same thing but runs perfect otherwise

 

I won't say I figured it out but it did stop doing it.
Since this post I have replaced all 4 solenoids in the transmission along with drain and filling it a few times with Type IV fluid. After some time driving it just stopped doing it. My guess is either the line pressure solenoid or the torque converter clutch solenoid along with more fresh fluid did the trick.

 

How did you re-seal the pan after dropping it to replace the solenoids?