Gear Rod 5-7 The Achilles Heal

[ARC550]

Originally Posted by V8munro

I got the 5-7 rod fault yesterday. Was at 1/4 mile strip for first time on mt's and was throwing dtm at top of fourth. Never seen the 5-7 issue before just had the adaptation issues earlier in the year. I full throttle my car alot but usually from 2nd upwards never really from a stand still which is when this occured. At the end of the day on my last run i also got a high trans temp error whilst warming tyres but no 4th issue on that pull. Ive done the adaptations again today at 75c and going to see how long she holds out for. My oil and filter is only few months old and mecha has been cleaned

It has begun... lol it will only continue to get worst.

[V8munro]

I know , im well aware of the issue unfortunately. Seems to be no definitive answer on the cause yet either.

[V8munro]

I think either the burnout raising trans temps or extra traction from the mt has made this show its head. Doing my normal high speed with r888r box has been behaved.

[allmotor_2000]

It’s inevitable...

[Sales@RKautowerks]

Anyone here have a transmission they've cooked? Looking to find one that is bad and needed to be replaced.

Thanks
-R

[M5Rlz]

For reference if you're snapping gears: torque and 63tus make a ton of it at low RPMS and heat.

Same way stock gtr gears can take 1000whp+ but you ramp the torque up too strong or do repeated pulls they'll fold like a lawn chair.

I'd say anyone making quick torque over 700 should monitor how their torque is coming on if they can via tune, and the heat they're generating on pulls.

[V8munro]

Such an annoying problem, ive only seen at the 1/4 but from what i see here its just going to become more and more common now until i change but i dont really want to be swapping out boxes every year or so

[allmotor_2000]

It gets worse and worse over time... best to order a spare DCT now

[V8munro]

Just about to kick off the engine rebuild so funds are tight atm, but i will be doing that for sure once cash available

[bm5bullit]

What is the cost of a new DCT, approximately?

[allmotor_2000]

$3-$4K...?

[Used2be]

Originally Posted by bm5bullit

What is the cost of a new DCT, approximately?

When I got the cost from a dealer some years ago it was $13,804 and I don't believe that included the clutch. This is for the complete transmission from the parts department, not installed.

[steeve13m]

Apparently a few F10 M5's have fixed this issue with a process to clean the DCT Transmission Mechatronics (issue is cause my metal deposits in the sensor magnets according to BMW and other techs)

Anyone on the board tried this successfully?

I am planning to do this process soon once I have the instructions

[M5Rlz]

Originally Posted by Used2be

When I got the cost from a dealer some years ago it was $13,804 and I don't believe that included the clutch. This is for the complete transmission from the parts department, not installed.

Thats not bad at all to be honest lol.

[allmotor_2000]

Originally Posted by steeve13m

Apparently a few F10 M5's have fixed this issue with a process to clean the DCT Transmission Mechatronics (issue is cause my metal deposits in the sensor magnets according to BMW and other techs)

Anyone on the board tried this successfully?

I am planning to do this process soon once I have the instructions

Tried it and didn’t work...

[V8munro]

Mechatronics on mine was cleaned beginning of this year with new oil and filter.

[allmotor_2000]

There are two parts to the mechatronics.

1. The TCU and the hall sensors
2. The valve body assembly

When you swap DCT's you have to move over the TCU portion to the new DCT else the car won't start (EWS system won't recognize due to VIN mismatch).

The issue is either with the valve body assembly or the DCT itself.

[wallyman424]

Originally Posted by allmotor_2000

There are two parts to the mechatronics.

1. The TCU and the hall sensors
2. The valve body assembly

When you swap DCT's you have to move over the TCU portion to the new DCT else the car won't start (EWS system won't recognize due to VIN mismatch).

The issue is either with the valve body assembly or the DCT itself.

Why can't the tcu module be flashed using esys like any of the other modules? Is there something that prevents that?

[allmotor_2000]

Tried ISTA-P doesn’t work...

[wallyman424]

Originally Posted by allmotor_2000

Tried ISTA-P doesn’t work...

Do you know if anyone has tried with esys? That seems to be how everyone codes the F cars. There are YouTube videos about flashing f10 ecu vin's.

Wonder if anyone else has any input on this?

[steeve13m]

Originally Posted by V8munro

Mechatronics on mine was cleaned beginning of this year with new oil and filter.

So the cleaning had no effect on your rodshift error?

I also heard there is a new bmw ECU update from March 2018 that helps fix this issue in conjunction to specific mechatronics cleaning procedure (getting the metallic dirt out of the magnetic sensors)...can anyone confirm?

[V8munro]

I have not heard about the gearbox update but thats interesting.

My gearbox did not have the 5-7 issue but would not adapt successfully so it was sent to ssp, it was cleaned but kris told me that it was already very clean once the box was returned it still would not adapt and after trying a number of things, ecu maps, removing jb4, using different laptop to adapt, going through rest of adaption procedures it finally went through and once successful has never had that problem again. Since the clean ive probably done 3000miles tops so i do not believe it is because it needs cleaning in my case. I had never seen this problem till i went 1/4 mile with MT tyres, the car in the last 3000 has been past 200mph about 10times, done probably 30-40 100-200 pulls but no never any launches as hard as the 1/4. I do not know if the extra heat from the burnout or the extra heat generated from the hard launch and traction is a factor that has caused this issue to arise but i think so. I have adapted the box at 80c gearbox temp and noticed a change in way its shifts so maybe mine was due an adaptation and that is the cause but from what allmotor says im prepared now for this issue to get worse and switch the box.