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2002 CLK320 convertible, 50K miles, ex. flood vehicle
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7 Posts
Discussion Starter #1 (Edited)
FIXED: RESULT IN POST #4 below. For the record. Thanks in advance for any help....

Vehicle:
2002 CLK320 with Autostick. 50,000 miles. Ex-flood.

Symptoms:
P0730 incorrect gear ratio (I think it thinks it should be in 4th but it isnt)
All gears work fine except for 4th. When car shifts to fourth gear for half a second it feels like it will shift and work, then goes into what feels like neutral and free revs. If I slow down so that the car needs to shift into 3rd or lower, the car will then shift and drive as normal in the lower gears. Autostick will let me shift through to 3rd but will act the same as above when shifted to 4th.
Tranny ran fine post flood after I serviced it. The symptoms happened about 30 miles later: when I went to get it inspected, the engine heated up to 120 degrees as the fan relay needs to be sorted. When I left the inspection station I could smell tranny fluid and the problem started.



Previous Knowledge and Actions
Tested pinouts to 1-2 and 3-4 solenoids. Both show 4.0 ohms vs 2.5-5 as acceptable. So seems Ok.
Tranny Fluid found in connector to transmission. Replacing with new pilot bushing, light wick towards TCU, however, TCU clean.
No metal in pan, slight dusting of black swarf. (I assume friction plate material)
I have taken the valve body and conductor plate out and am inspecting.
Replaced filter, fluid, replaced shifter with used shift lever, post flood. The TCU was dry and clean as it hangs upside down and fluid was held out by trapped air.

Questions and Logic:
Can fluid in the connector to tranny cause 4th gear to not shift? I know that technically tranny fluid is an insulator and not a conductor, unless of course enough graphite or material is in the fluid.

Possible 4th gear valve?

Shift lever was used when installed....could this be the suspect if only 4th gear is not engaging?

Could the conductor plate be shorted?

Again, all works well except 4th. The car tries to shift to fourth, yet it doesnt engage and free revs.

Thanks for any leads or feedback experience
 

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'01-E320 & 02-ST2
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31,631 Posts
I would first clear the code; so long as the code is stored it is going to do odd things, even if you fix the problem. Heck, even if you replace the transmission.

You can't clear it with standard OBD-II readers, though, it takes one that will talk through to the TCU. Obviously a dealer, or indy, or shop with snap-on, etc. Aamco says they will read codes for free, maybe they will clear it for a nominal charge.

Oh, and please take a moment to click user cp and edit details so you can add your vehicle and location to your profile, it's often useful information when you're seeking assistance. Not much sense mentioning Aamco if you're in the Sicily, for example. ;)

Good luck.
 

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Registered
2002 CLK320 convertible, 50K miles, ex. flood vehicle
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7 Posts
Discussion Starter #3
Thanks, I will get the codes cleared after reassembly. Profile created.

Any other words of wisdom?
 

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Registered
2002 CLK320 convertible, 50K miles, ex. flood vehicle
Joined
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7 Posts
Discussion Starter #4
Fixed: verdict- fluid in the connector. Pin #9 was shorting to the ground in the connector nut. Fluid is supposed to be an insulator, however, sure as anything, it was grounding out and not getting power to the 3-4 shift solenoid. Everything checked out OK. The reason for the p0730-incorrect gear ratio is that the car thought is was in 4th as it was sending power to the solenoid, whereas it really just stayed in neutral. This results in the wrong ratio between the input and output shaft. Simple fix for the record.
 
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