GS430_95

Okay so here's an update. I collected the car today and drove it home, it was motorway driving to get home, which it did fine before anyway. After having some lunch, I took it on a short drive around where I live, and I drove it on 3 sections of road I know I have experienced the shudder before, multiple times. It did not shudder today. I can't 100% tell if this is because I'm thinking about trying to make it do it too much, or if it's actually gone. Not 100% convinced yet, I will have to drive it a bit more and keep a close eye on it. But so far so good. Fingers and toes crossed!

Hopefully next week I shall have an update. Gearbox has been flushed and filter replaced, but I don't have time to collect the car until next week.

Yeah, the cars already had a new radiator fitted previously, so I assume that they’re not mixing now, but there’s still traces of coolant in the transmission that need flushing through. Is there any way to tell if they’re still mixing or not? I’d like to assume not because of the replacement radiator, but want to be sure.

So I’ve done 1 fluid change (not flush as couldn’t find anywhere close by that could do it..), the fluid that came out was like Yazoo milkshake lol. The gearbox still shudders, but it’s definitely not as bad as it was. It also changes a lot smoother. The plan is to do a few hundred miles then do it again - next time I will ask them to remove the sump and clean it out. Anyone interested in buying it yet? I was going to sell it before summer anyway so don’t want to keep throwing money at it 😂

Thank you very much for your help @twolexii . I can’t help but feel that I’ve bought a dog and wasted my money, even though I was trying to be cautious. I will try and do some more investigating and hopefully I can get it sorted. Thanks again!

Hi, I'm not sure to be honest! What do you think? Was trying to gauge an idea from this thread. Thanks.

Hi everyone, I’ll jump straight to the chase. A couple of months ago I bought a Mk3 GS430 (2005 with 95k on the clock) and it has a small issue with the transmission. What I fear has happened is that the coolant has ended up in the transmission, as the car has had a replacement radiator and fluids. There is a shuddering coming from the gearbox every now and then, but the car drives fine 95% of the time and you’d never know. Keeping my options open, if a fluid change doesn’t resolve this, then I’ll probably end up selling the car and buying a MK1 MX-5... What would it be worth in its current state? It’s in pretty good condition, a few marks on the rear bumper, and one slightly kerbed alloy (which I can get fixed), and will have 12 months MOT on it. Interior is nice and everything works as it should. It has full Lexus history up to October last year, and has had an oil change since. Really, the only thing wrong with the car is the annoying gearbox shudder. Tyres are okay, still plenty legal but not amazing. I’m just trying to plan the future of this car a little better, currently it’s at the workshop awaiting MOT. Thanks. Ian

Thank you. I will get it flushed through and do a fluid change then see how it is.

Many thanks for your help @ColinBarber - looks like that's the next step then. If there is still traces of water in the transmission, and I then get the transmission flushed & replaced the transmission fluid, will this stop (or lessen) the shaking from the gearbox? Or is this permanent and it will just stop it getting any worse. Apologies for all the questions, just trying to get an idea of what I'm up against...

Hi, thanks for your response! The coolant all looks fine to me, however the previous owner did mention he replaced the radiator and coolant, as well as did a gearbox oil and engine oil change. 3 of those things ring alarm bells straight away, however I wasn’t aware of this issue until I already bought the car... doh! My worry is that it has had water in the gearbox at some point and it’s caused irreversible damage

Hi everyone! New member here. I'm certain there are a few threads on this issue, but can't find many at the same point I am at. I purchased a 2005 GS430 last month, absolutely fantastic car and it drives really well, had no issues with it until a couple of weeks after I bought it. I was driving through a village and accelerated up to 40mph from 30mph and the whole car shook almost as if I was going over a rough patch of road. But the road was completely smooth. It then did the same thing again, same speed on a different patch of road. I suspect this is down to the transmission. I tried to replicate the problem but could not get it to do it again, however there is obviously a problem somewhere. I am aware (now) of the coolant making its way into the gearbox and causing issues. I'm not really sure where to go from here though. I am going to get the gearbox oil changed, however it looks like the previous owner already did this (alarm bells I know, but too late now). If the problem persists I don't really want to spend £2k+ getting the gearbox rebuilt or even £1k for a used one, I'd rather just sell it at that point. The car is fine otherwise, if the gearbox is damaged it must be fairly recent and it works fine other than this slight murmur. What's the best steps to take from here? Thanks.