Why Shifter Lever Assy breaks on Jeeps

[a137]

After several short term "limp modes' followed by famous 'circled" PRND on EVIC decided to check SLA module, also known as electronic shifter module (ESM), inside. Several people here claimed that after replacement of SLA module they got rid of the problem.

I started with some homework and found German (Mercedes) white papers about 722.6 gearbox. Documents stated that inside the module there are 12 Hall sensors to detect lever position. Hall sensors are known as pretty reliable ones cause they are contact-less sensors. Interestingly, I didn't found any claims on SLA module on several Benz sites.
However when I disassembled SLA module, I found that Chrysler put cheep mechanical contact system inside instead of just a bit more expensive but far more reliable Hall sensor system.
My guess is that it might be a main reason of SLA module failures. Most of them are reported at 30K-40K mileage, right after starting the car in cold mornings. Morning condensation along with a sufficient amount of conductive material accumulated between lamelles may cause position misreading.

The good thing is that it's possible to clean them using contact cleaner, which I did. By the way Chrysler says that it's non serviceable unit and wants more than 300 bucks for part only.

This is picture of PCB

These are lamelles before cleaning

After cleaning

Contacts are different - gold plated for gear position and nickel plated for autostick


I think that's one of a good examples, why Chrysler cars have worst reliability figures than Daimler ones.

[SJG3RD]

After you cleaned them is everything good to go now?

[a137]

So far, yes. I will update within this week.

[FriscoHemi]

interesting - great research!!!!

[Knuckles]

Originally Posted by a137

So far, yes. I will update within this week.

Good work man! I see what you found, but how long do you think this will last? Because when you get a new board the contacts on it will be a light gold color. So after many years of use I can see why the contacts on the board turned Black from all the friction. My guess is that this is just a band aid fix and the problem will be back again bro. Keep us updated!

[veyronSRT8@TTCreations]

sweet find my man, keep up the good "inspector gadget" work.

[a137]

Originally Posted by Knuckles

Good work man! I see what you found, but how long do you think this will last? Because when you get a new board the contacts on it will be a light gold color. So after many years of use I can see why the contacts on the board turned Black from all the friction. My guess is that this is just a band aid fix and the problem will be back again bro. Keep us updated!

Nope, these contacts are coated by conductive material a kind of graphite. So they are always black. The problem is that surface is teared because of friction and gaps between conductive contacts eventually become conductive as well. I just cleaned the gaps. How long it will last? At least not longer than mine current 25 kmiles.
I will look for protective grease, that was used for similar sliding contacts inside old VHS/Betacam decks. Not easy to find now.

By the way, I used to have a bad (previously I considered it as a "cool") habit - to hold my right hand on shift lever during driving - it could contribute to premature wear also.
People who have replaced their ESM may confirm or deny this proposition.

[a137]

Originally Posted by veyronSRT8

sweet find my man, keep up the good "inspector gadget" work.

Thanks, I have to keep researches. You people have warranty, dealerships in any small town and even road assist. Here I am 10000 miles away from "warranty", I have to double-check before ordering parts.

[a137]

Ran approx 600 km, 4-5 stat-ups daily. No limp modes and EVIC messages.

[Knuckles]

Originally Posted by a137

Ran approx 600 km, 4-5 stat-ups daily. No limp modes and EVIC messages.

Thats good news! Keep us posted man!