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GS430_95

GS430 Gearbox

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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.

 

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If you think there could be coolant/ATF mixing then you want to be sure ASAP. Look at the coolant to see if there is an oil film on top. I assume this is a series III with the 6-speed transmission and no dipstick? If so then you may want to take off a transmission line from the radiator to look at the fluid - if it is red or brown then it is ok, if it is pink/cloudy then coolant has mixed and you shouldn't drive it.

The vibration could be something else, for example an engine/transmission mount/prop shaft with play in it which should be easier to fix.

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10 hours ago, ColinBarber said:

If you think there could be coolant/ATF mixing then you want to be sure ASAP. Look at the coolant to see if there is an oil film on top. I assume this is a series III with the 6-speed transmission and no dipstick? If so then you may want to take off a transmission line from the radiator to look at the fluid - if it is red or brown then it is ok, if it is pink/cloudy then coolant has mixed and you shouldn't drive it.

The vibration could be something else, for example an engine/transmission mount/prop shaft with play in it which should be easier to fix.

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 

 

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You may want to take a sample of the transmission fluid and get an oil analysis on it. There are several companies in the UK that perform this - you want to know the amount of water in it. I've not used any of these companies so cannot recommend one but just google transmission oil analysis uk and you will get some results - maybe worth calling them to make sure they will be able to detect coolant as part of their test before ordering. Costs around £30.

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4 hours ago, GS430_95 said:

 

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... 

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It is very difficult to say.

The first thing to check, which I should have mentioned, is to get the level checked. If it is low then you can experience shuddering. If there was coolant in the transmission then you need to refresh as much of the fluid as possible (not just a drain/refill of the pan) and change the filter. Whether the water as affected the clutches isn't possible to know without stripping it down or just seeing how it performs.

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11 minutes ago, ColinBarber said:

It is very difficult to say.

The first thing to check, which I should have mentioned, is to get the level checked. If it is low then you can experience shuddering. If there was coolant in the transmission then you need to refresh as much of the fluid as possible (not just a drain/refill of the pan) and change the filter. Whether the water as affected the clutches isn't possible to know without stripping it down or just seeing how it performs.

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

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