chylld

Hi Daniel, I'm considering taking the plunge with an M150 into my Exige 350 w/ CC 1900. 405-415bhp at the hubs doesn't seem like a significant improvement over the 400bhp@hubs shown in the Harrop CC 1900 video below (at 4:40). Please tell me I've got my wires crossed somewhere? I'm also not sure which numbers were achieved using aftermarket headers and/or exhaust.

Apologies for reviving an old thread... my auto 400 is also stalling. However it's only happened twice and both times I've been able to restart the engine with the start button and then pop the car back in D (goes to N automatically on stall) My MAF sensor looks pretty snug, worth cutting the ziptie to check the connection? Or the sensor itself?

Happy days... after about 5 more drives the sound appears to be completedly gone. The shifts are noticeably smoother and faster too, although I did manage to confuse it once yesterday by jumping from the brake to the gas while it was mid-shift. Picked a gear within a second though, whereas before it sometimes hunted for what seemed like an eternity. Going to change my gearbox oil more frequently now... at least every 5 trackdays or every year (along with engine oil), whichever comes soonest. Good info, another 2 products in the service manual: Toyota Genuine ATF WS Transmission oil (what I got) Exxon Mobil JWS 3324 Transmission oil

Got the car back. Only good news to report so far... car drove home perfectly fine. No sign of shift hesitation and I can't reproduce the clunk sound anymore by reversing a few metres and then going forward a few metres (which reproduced the clunk 100% of the time before.) Will pay close attention to it tomorrow, but happy to say it's all looking good so far. After all the service manual does recommend changing trans oil every 7,500km/6 months for regularly tracked cars (as opposed to 58,000km/4 years otherwise.) The dealer also checked the spark plugs but confirmed they were fine (as they should be, after only 8,000km). Haven't had it checked explicitly, although it appears to be ziptied from the factory:

1 year 2 months, Supercharge Gold MF66. Was put in 6 weeks after I took delivery of the car (factory Varta already started having issues.)

Just dropped my car off for service. Not without drama though; on the way there, in a congested tunnel, the car stalled. (It's an automatic.) Have been noticing a few coughs/splutters every now and then (regardless of engine temperature or fuel level) but this is the first time it's totally stalled. I was decelerating in D(rive) at about 20mph/30kph when the engine cut out. Engine light, battery light and oil light came on, and the gearbox went into N by itself. Was able to restart the engine with the starter button while rolling. Dealer ran diagnostics asap, but nothing came up. The last week or so the car has really been struggling to start... it barely ticks over and then runs really lumpy for about 10 seconds at 500rpm before smoothing out. I've had this before with a bad battery, but I'm currently on a relatively new one. Dealer is going to check the spark plugs, but I suspect it's a fuelling issue. Fingers crossed the car is all well and better when I pick it up this afternoon....

Interested in something lighter and a bit quieter for my 400. QuickSilver exhaust sounded like it was the go but Bell & Colvill told me they weren't selling them due to quality reasons. Would be interested in the Signature QT if/when it becomes 400-compatible.

Car is booked in for service next Wednesday. Downside of the dealer being a race team is that they have to prioritise those preparing for competition first. A flurry of events this month meant that I had to be pushed back several weeks. (Missing one of my own trackdays in the process but it wasn't a competition event anyway) Also kinda hoping that fresh transmission oil helps with my fuel consumption... the car is only getting about 150 miles before the fuel light comes on. (Driven on the street very sedately)

Thanks guys, look forward to getting it sorted out. Very strange to hear that the manual is also prone to such a noise as all my symptoms point to the auto box. This morning driving to work it even hesitated on upshifts in a straight line or perhaps I'm paying more attention to these little hiccups than I normally would. Have another big rattle coming from the back of the car somewhere on bumpy roads. Sounds kinda similar but is just a sound, as opposed to the main clunk which can also be felt through the seats.

Cancelled my trackday. Driving home from work I tried to upshift during a long sweeping corner at moderate Gs... box couldn't find the next gear until after the corner. Previously that had only happened occasionally on track. (upshifted well before redline, so not a rev limiter issue) Also just heard from another friend with an auto Evora 400 - he has the same clunk now too.

My dealer called today to say they can't change the transmission oil until a month from now... too busy setting up race cars for a few events until then. Hoping the gearbox holds together, I have a trackday in 2 weeks and the clunk has developed into the occasional double-clunk

Thanks so much for the info Really hoping an oil change fixes it.

Yes happening in all modes. Some further research into the U660E auto box reveals that some Toyota owners have similar sounds in their cars. In their cases it's either the ABS doing a self-test (only once per engine start-up though) or an indication that the transmission oil needs to be changed. Booking my car in for a gearbox oil change as the service notes suggest I do so about now anyway. Normally required every 58,000km / 4 years, unless the car is tracked "occasionally" in which case it needs to be changed every 7,500km / 6 months. (My car has done 8 trackdays and 7,800km)

Good thinking, however unlikely as the clunk still happens if I hold the car in 1st gear at 20-30kph and then slow down to 0 (so no gearchange).

Today I checked if tension on the handbrake affected the noise at all; it didn't. So as you suggest, torque converter is looking even more likely to be the culprit. No warning lights so I think it's purely a physical fault. I get the noise regardless of engine/transmission temperature.