GS430 - Transmission issue/niggle

[JDM-Fiend]

Hi all,

I've got a 2005 Lexus GS430, which I purchased last August.

It's been a great car and I've managed to cover around 12,000 miles in about a year, so I've driven it loads. It's currently just over 117k miles, which I understand to be nothing for this engine.

Since owning it, I've found out the car has the torque converter shudder (I'm fairly certain from chats with transmission places and the internet research I've done) that I've read about that affects the LS430/GS430 and SC430 (A761E transmissions basically).

I've been going back and forth for a long time about whether to sell it as is or to fix it. I've now decided to fix it and keep the car, just because I like driving it so much. But, the torque converter issue is tarnishing the drive and general enjoyment.

The fault described:

When driving on a slight incline between 35-40mph with a gentle throttle, there's a sudden shake/judder/vibration to a varying degree - much like driving over a cattle grid. It can last what feels like 1-3 seconds. I get a much shorter abrupt version of the same issue, when driving 65mph+ when trying to keep a constant speed.

I've had the fluid changed twice with the proper Toyota WS ATF fluid, the fluid was pretty cherry reddish when changed. I also had a new OEM transmission filter fitted too. I've also had the separate gearbox oil radiator installed, which I purchased from Lexus Spares Direct on eBay as a preventative measure for the potential radiator issue that affects the 430 models. (LS/GS to my knowledge)

Currently, I drive 1000-2000 miles a month and it's the perfect mile muncher and I get 28-32 mpg which is fairly respectable in my opinion. I'd only consider changing it for a GS250 F Sport, but not quite yet.

I understand my options to be (feasible or not, they are all options):

• Go to Lexus to get it replaced (Just a new gearbox, I was quoted £6k odd without labour) - Least likely option - Total cost likely to be over £7k
• Get a used gearbox fitted (very little warranty and recourse if it goes wrong) - Total cost likely to be between £1500-£2000
• Go to a transmission specialist to get the gearbox reconditioned, which I believe in my case it would be a case of a new torque converter (I'm going to 2 next week to get a definitive diagnosis) - Total cost likely to be between £2000

The point of this thread is to but I wanted to hear some opinions (especially those who have been through this issue). I've already got a pretty good idea of what to do next, but it's always good to hear from some hopefully pragmatic and sensible people on the matter.

Thanks

 

[Mike_Mac]

I am neither pragmatic, nor sensible, but my 2p (having no direct experience of this issue, to be fair) is that the last two options are both valid, but depend on three things.

First, whether it’s just your Torque converter that’s at fault - in which case, replace is the simplest option.

Second, whether you can find a used ‘box that you can actually observe working before fitting, which is a big question mark.

Third, the deciding factor of cost vs benefit. A used ‘box is cheaper but more risky, whereas with a new converter you have new parts, not used, and a warranty, so more cost, less risk.

personally I like doing things once and minimize risk - so would personally go for a new converter.

/2p😉

[JDM-Fiend]

On 9/9/2022 at 1:00 PM, Mike_Mac said:

I am neither pragmatic, nor sensible, but my 2p (having no direct experience of this issue, to be fair) is that the last two options are both valid, but depend on three things.

First, whether it’s just your Torque converter that’s at fault - in which case, replace is the simplest option.

Second, whether you can find a used ‘box that you can actually observe working before fitting, which is a big question mark.

Third, the deciding factor of cost vs benefit. A used ‘box is cheaper but more risky, whereas with a new converter you have new parts, not used, and a warranty, so more cost, less risk.

personally I like doing things once and minimize risk - so would personally go for a new converter.

/2p😉

Thanks Mike.

Pretty much echoes my thoughts, I'd rather pay more, have a warranty and know it's the best option for longevity and the 'right thing' to do.

[JDM-Fiend]

Small update - my car is with a transmission specialist who are refurbing the gearbox completely.

Turns out there was water within the gearbox, which may or may not have been related to a radiator issue. Luckily, I have an aftermarket radiator fitted to cool the gearbox - so that's a weight off of my mind.

 

[Mike_Mac]

That’s bad news, but at least you’re getting it sorted and stopping the root cause!

[JDM-Fiend]

An update on this, I bit the bullet and had the transmission refurbished. It cost a total of £2960, but I'm glad I did it as the odd shudder and hesitation was driving me (no pun) up the wall. I used Gravesend Transmissions who definitely know their stuff, unlike some of the cowboys I've encountered! You definitely get what you pay for.

 

There was water in the transmission, so looks like past owners ignored or concealed it from one another, including the person who sold it to me. But, I've sorted it now and it drives fantastically well now! Very happy!

[Malc1]

Brave man, well done .........  just goes to show the 100k mile / 10 year programme to replace the radiator should have been adhered to by a prior owner to have probably avoided the issue

Well done

Malc

[Mike_Mac]

Glad to hear it’s been sorted! 😃