Trans goes "clunk" when driving along at a steady speed of 30 mph

garrett.fell · #1 05-15-2015, 05:53 PM

Anyone have anything like this happen? I've noticed this happening a couple times over the last few months. It's always been on the same little stretch of road with a 30 mph speed limit over quite a distance. Maybe a mile or so.....

I am holding the speed at a steady 30ish and I get a little "thunk" from what seems like it could be the transmission. I can feel the car slow slightly then it goes away. It's hard to reproduce but have had it happen a couple times in a row. It did it to me today and maybe a month ago.

It's almost like the trans is thinking about shifting but then decided not to. Either that or it's some sort of engine miss.....

Does this sound at-all familiar to anyone? Other than that the trans shifts and behaves fine. Car has 112k on it.

Thanks!

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admranger · #2 05-17-2015, 06:29 PM

Maybe check wiring harness at the transmission?

I forget, have you done a fluid/filter change? If not, sounds like it may be worth thinking about...

Also, our transmissions were used in Jags too, so google search this as it may have happened on another vehicle.

ScoobyDooBMW · #3 05-17-2015, 11:05 PM

Sounds like mine to point. Mine does that between 30-40. I've pinpointed mine to 5th gear. When I do a manual shift and shift between gears, It does it when I'm in 5th gear. I'm not sure why it does it but that's what I've figured out. I plan on doing a tranny flush and hope that will help.

PropellerHead · #4 05-18-2015, 11:21 AM

Quote:

Originally Posted by ScoobyDooBMW

Sounds like mine to point. Mine does that between 30-40. I've pinpointed mine to 5th gear. When I do a manual shift and shift between gears, It does it when I'm in 5th gear. I'm not sure why it does it but that's what I've figured out. I plan on doing a tranny flush and hope that will help.

This sounds like the last of the symptoms that I wrote about before a fluid service, a small part, and firmware update fixed this and other issues for me. Hopefully it'll help you as well.

garrett.fell · #5 05-18-2015, 02:27 PM

Quote:

Originally Posted by admranger

Maybe check wiring harness at the transmission?

I forget, have you done a fluid/filter change? If not, sounds like it may be worth thinking about...

Also, our transmissions were used in Jags too, so google search this as it may have happened on another vehicle.

I have not changed (or even checked) the trans fluid on this car. I put about 70 miles on the car this weekend and only one episode of this. It's hard to explain - it happens really quick. It's like the car "bucks" or "hiccups" for lack of a better word for it.

The last time this happened it was on the tail-end of about a 20 mile ride which included a little jaunt on the interstate. 60-80 mph

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PropellerHead · #6 05-19-2015, 11:52 PM

Quote:

Originally Posted by garrett.fell

I have not changed (or even checked) the trans fluid on this car. I put about 70 miles on the car this weekend and only one episode of this. It's hard to explain - it happens really quick. It's like the car "bucks" or "hiccups" for lack of a better word for it.

The last time this happened it was on the tail-end of about a 20 mile ride which included a little jaunt on the interstate. 60-80 mph

I had done mine with the filter at 30k miles. I am at 65k now. I think fluid was just part of the problem. Of course, I will still probably change the filter and fluid again at ~90k. 'Cause why not, right?

garrett.fell · #7 05-20-2015, 09:00 AM

Hmmmmm. I've read all of the "debate" on to-do-or-not-to-do and I've decided I am rather undecided on the subject. I am leaning towards giving it a shot......um. Maybe. Maybe the filter-pan at the very least and a partial fluid change

Car has 112k miles. I bought it 4 years ago at 73k miles. It was my wife's daily for 3-years and now it's my weekend cruiser or my-ride when I decide I wanna roll in something cooler than a Honda CRV. I think I've put about 2500 miles on it in the last year....

I'll be taking it out tomorrow for about a 40 mile run round-trip. We shall monitor the situation for now.

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garrett.fell · #8 05-21-2015, 10:26 AM

Well crap - it did it to me again this morning. Car fully warmed-up after a 15+ mile drive. Driving along at a steady 30 mph then a single "buck" or "hiccup"

I guess I'll hook it up to the laptop when I get home tonight and see what the car thinks....

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garrett.fell · #9 05-21-2015, 10:37 AM

Quote:

Originally Posted by PropellerHead

This sounds like the last of the symptoms that I wrote about before a fluid service, a small part, and firmware update fixed this and other issues for me. Hopefully it'll help you as well.

About 3 years ago or so - I did take the car to my Indy and had them update the transmission control software. My primary motivation at the time was to "fix" the rolling-stop-and-go "jolt" I was experiencing. It seemed to help

Does anyone know how I might check this with my laptop with the Romanian software suite?

I did reset the transmission adaptations about a month ago.....that was interesting as the trans "re-learned" how to behave. The first dozen shifts were a bit rough....lol.

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