sst clunk when turning ignition off
 

2008 X MR, mods to 300kw. high mileage (nearly 300,000 km, almost certainly the highest mileage MR in the world from my forum exp). Several months ago I hit a dead kangaroo which smashed the undertray and ever since (may or may not be related) my trans has gone "k'chunk" and jerked forwards on switching off. This happens regardless of whether the car is in park or neutral but seems to be much worse when it's hot. Any ideas? Thanks!

I should add that the car is obsessively looked after, serviced every 10,000K (approx 6200 miles) and never tracked, although the mileage is very high it's 90% highway cruising around 110 kmh (72-ish mph), and the power has been wound back from a high of 404KW ATW to 300KW at the crank. The clutches are original (!!) and the SST transmission fluid, whilst non-stock, was put in by TMR Australia who know what they're doing, less than 100,000k ago. (bout 70,000 from memory. Mitsu recommends every 100K)

found your problem...

So how would that cause the problem I'm describing? Surely if it was the SST fluid there'd be issues with the clutches hooking up and issues with shifting as well as the problem I'm describing? (there isn't) And the problem only occurs when the car's hot, and only in the last 5000k, whereas the fluid has been in there for a fair bit longer than that. Also I doubt TMR would risk their reputation with dodgy trans fluid. As far as I can tell the only difference was it wasn't $118 per litre. I appreciate your reply, but i'd already discounted the fluid as the problem- which is clearly mechanical.

Hey I get it, not what you wanted to hear. I have never heard of TMR but I can tell you that every reputable shop in the U.S. advocates nothing but OEM Diaqueen MR-SST fluid. You can find countless threads about this if you do some searching.

TMR are Team Mitsubishi Ralliart Australia, and whilst i'm not here to sing their praises (mainly because they're only really interested if you have unlimited funds for them to prep your Targa racecar), they almost exclusively deal with Mitsus and mostly Evos at that, so (maybe naiively) I assume they know what they're doing, and if they use cheaper fluid I'd hope they've done the appropriate R&D. I'm going to replace the stuff they used with Diaqueen (at five times the price) and we'll see if it helps. In the meantime, if it's the fluid, any idea what exactly is happening?

Are they affiliated with Mitsubishi? You could give them the benefit of the doubt, maybe they have access to stuff we don't have in the states. Give them a call and let them know whats up, and see what they have to say.

Did changing the sst fluid work? I have the same issue.