CynCarvin32

So I put my SL55 on the dyno a bit ago just to see how it would do. I have no mods and never have had any.

So I put down 408 and 468 tq stock on a dynapac and that was ok since the dyno normally is a bit low.

I went to drive home and the car would not complete a 2-3 shift correctly. It would rev up well above the shift point after the clutch disengaged the gear. It was just freely reving until it fell back into the next gear (third). Every shift was bad and it would only do a normal (ish) shift if you totally lifted off the gas during the shift.

I took the car in the next day (under warranty ELW) and the car was diagnosed as having broken freewheels and needing new K3 gear sets and freewheel assembly.

I got the car back 1 day later and its all fine again.

Am I the only guy to actually break a trans on the dyno? Whats the deal with LOAD dyno's vs. INERTIA Dynos? The car did do a downshift or two on the first two pulls (thrid to second) and it did shift at redline from 3rd to 4th.

Did I do something wrong with the shop (was in dyno mode) or does a load dyno just cause so much stress that the car said forget it and broke.

Tell me your stories if any!

Thanks for the info.

shardul

iTrader: (1)

**** first time I have heard of this

chiromikey

did you take it out of dyno mode before you drove home? there are several cases of the trans locking into gears or going into limp mode if driven in dyno mode for extended periods of time.

CynCarvin32

Yes i had it back in standard mode in the driveway leaving.

This problem was more than sticking gears. It was for a lack of better terms a "freehweeling" transmission between the point where the clutch for second released and the clutch for third engaged. Normally a freewheel controls the transmission speed between shifts but mine died in the dyno pulls. It should only spin in 1 direction but it was spinning freely in both.

After the my tech replaced the three inches (in text form) of parts on the RO the car shifts just fine.

My adaptation values were all 100% fine and the car never threw an error code even when broken. Values below 80 are what the factory calls ok and all mine were between 8 and 35. This means my clutch's were working fine and were not worn. K3 had to be replaced because the freewheel is housed inside that K3 clutch.

c32AMG-DTM

For those that might not be fortunate enough to be under warranty - what was your repair bill quoted to be?

CynCarvin32

That is a good question. Let me post that tomorrow. I bet it would be 2-3k.

prodigymb

trans + torque converter + tcu = $7500 with labor at MB

CynCarvin32

Checked with my service writer and it would have been about $2,500 for the repair. parts were pretty cheap but it was 12 hrs of labor.

Ali_E55

so it wasn't the thrid gear broke ?


i had a similar problem with my old E320, where the 4th gear does not engage, it revs high in 3rd and then shifts to the 5th with a hit and a jump.

it cost me about the same amount of money, they said they replaced the third gear @@

Autoscope

Well, a couple of things...

Either it was wear and tear....and for some reason the Dyno helped it break?

Poor dyno operator, he could of "over" loaded the car alittle and it stressed some things....

I don't think it had anything to do with the dyno unless he used the wrong factors....

dyno

please post your dyno test result .. just curious to compare with the same test on a load or socalled "Braked" dyno I did when stock.
how many revv points did they tested the engine at ?

I suffered so much for my car when they did it that not sure I will not do it again ... it is so hard for the engine because it works like this way: it tests the real torque strenght the engine is able to develop for the given rpm value it is testing.
like if something pulls you back when you are striving at max load ... it really "brakes" you for testing, first thing, if you resist that load and, secondly, how much torque you develop, while it keeps you braked