Transmission Help Gear Implausible.

**Sublime130** · 11-12-2009, 09:11 AM

Looking for some assistance from someone else in my field.

I have perplexing NAG1 (Mercedes car) with issues. I am a longtime member of ATRA & ATSG and they don't have an answer to my issues. I have had it to the Mercedes dealer and no help there - of course.

In a nutshell - had "gear implausible" & communication codes - which I see a lot of. I changed the contact plate retried and the comm. codes were gone. Pulled the unit and the K1 & K3 C clutches were bad and the bushing - did the overhaul. Planets were verified as right ratio.

Still have the "gear implausible" codes. Checked the computer - correct.

Any dealer tech or transmission guys (hint, hint) that have had nagging "gear implausible" codes (pun intended).

**Popeye's Hemi** · 11-12-2009, 05:06 PM

Did you change the TCM or PCM or maybe upgrade to a newer setup. Seems the can bus may have crossed signals or the software versions are different.

Originally Posted by Sublime130

Looking for some assistance from someone else in my field.

I have perplexing NAG1 (Mercedes car) with issues. I am a longtime member of ATRA & ATSG and they don't have an answer to my issues. I have had it to the Mercedes dealer and no help there - of course.

In a nutshell - had "gear implausible" & communication codes - which I see a lot of. I changed the contact plate retried and the comm. codes were gone. Pulled the unit and the K1 & K3 C clutches were bad and the bushing - did the overhaul. Planets were verified as right ratio.

Still have the "gear implausible" codes. Checked the computer - correct.

Any dealer tech or transmission guys (hint, hint) that have had nagging "gear implausible" codes (pun intended).

**Hemi31** · 11-12-2009, 05:13 PM

Originally Posted by Popeye's Hemi

Did you change the TCM or PCM or maybe upgrade to a newer setup. Seems the can bus may have crossed signals or the software versions are different.

You missed the part where it's not an LX.

**formerice** · 11-12-2009, 09:08 PM

My transmission started acting wonkey at about 150,000 miles. I seem to remember the same thing. Also my friend with scan tool said it had a tone ring failure. Before he fixed it I found a nearly new one from a low miles 07 Daytona for $500 on ebay. Seriously, I wonder how different the MB TCU is from ours. Is it driveable now? Sorry no answers, but pm one of the transmission builders here.

**fnkychkn** · 11-12-2009, 09:34 PM

not sure how MB calculates proper gear/mph ratios but if it's anything like LXs, tire size could affect it.

**Lajus007** · 11-12-2009, 09:37 PM

talk to bill at paramount....i think i read in a benz forum where he was doing some work for benz owner...i maybe wrong...but if he know the lx nag...then he know the benz nag...

**Sublime130** · 11-13-2009, 11:16 AM

Thanks for all the suggestions. I am working on getting a hold of Bill now.

This one is just very perplexing so I figured I would throw it out there.

ATSG and I have been in daily contact & I am now leaning towards a CAN Bus communication problem.

**JonW** · 11-13-2009, 11:43 AM

Diagnostics should tell you if there was an intermittent CAN bus communication problem. At least the LX computers log and store it for later reference.

**Chryslertech** · 11-13-2009, 03:57 PM

Originally Posted by Sublime130

Looking for some assistance from someone else in my field.

I have perplexing NAG1 (Mercedes car) with issues. I am a longtime member of ATRA & ATSG and they don't have an answer to my issues. I have had it to the Mercedes dealer and no help there - of course.

In a nutshell - had "gear implausible" & communication codes - which I see a lot of. I changed the contact plate retried and the comm. codes were gone. Pulled the unit and the K1 & K3 C clutches were bad and the bushing - did the overhaul. Planets were verified as right ratio.

Still have the "gear implausible" codes. Checked the computer - correct.

Any dealer tech or transmission guys (hint, hint) that have had nagging "gear implausible" codes (pun intended).

Did you replace the torq. converter?I had several LX NAG cars with that code and it was a bad torq. converter.Not sure with the Benz. cars, but on the sprinter van you need the correct rear axle ratio programmed in the TCM or you will get ratio error codes.Also check free wheel clutches(one way clutch) and valve body shift valves for sticking.

**Sublime130** · 11-13-2009, 07:20 PM

Originally Posted by Chryslertech

Did you replace the torq. converter?I had several LX NAG cars with that code and it was a bad torq. converter.Not sure with the Benz. cars, but on the sprinter van you need the correct rear axle ratio programmed in the TCM or you will get ratio error codes.Also check free wheel clutches(one way clutch) and valve body shift valves for sticking.

On it. The clutches in the converter were fine. Valve body is latest part number with the latest TCM for the vehicle, and no stuck valves. Even tried another one today. The trans had the early sprags in it, but they have been updated to the 22 element.

Going to another Mercedes tech here in town on Monday. Thanks for all the input. Just trying to explore all avenues for a fix on this thing, it's driving me nuts.

**SouthernHotrod** · 11-13-2009, 07:28 PM

Originally Posted by Sublime130

On it. The clutches in the converter were fine. Valve body is latest part number with the latest TCM for the vehicle, and no stuck valves. Even tried another one today. The trans had the early sprags in it, but they have been updated to the 22 element.

Going to another Mercedes tech here in town on Monday. Thanks for all the input. Just trying to explore all avenues for a fix on this thing, it's driving me nuts.

Give us a call on Monday.