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Why Shifter Lever Assy breaks on Jeeps

172K views 127 replies 74 participants last post by  Oberlanderperformance 
#1 · (Edited)
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.
 
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#2 ·
After you cleaned them is everything good to go now?
 
#3 ·
So far, yes. I will update within this week.
 
#5 ·
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!
 
#8 ·
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.
 
#9 ·
So, after two weeks I confirm that's a real fix

Ran approx 600 km, 4-5 stat-ups daily. No limp modes and EVIC messages.
 
#12 ·
wow very intresting.
 
#13 ·
Great information...what kind of contact cleaning solution are you talking about...sorry i dont understand what this is exactly.
 
#17 · (Edited)
OK
First check this tutorial - how to remove shiny bezels and shifter knob
http://www.wkjeeps.com/interior_trim.htm#SHIFTTRIM
http://www.wkjeeps.com/interior/wk_shift_knob_remove_01.jpg

1. remove chrome bezel
2. remove aluminum bezel and knob
3. remove rubber insert from the storage pocket
4. remove 4 Torx10 screws
BEFORE

5. Put shifter in N or D, detach wiring harness and remove shifter assy itself sliding it by shifter rod upwards, as I remember it's fixed by 4 screws or clips. Don't remember exactly, but it's straightforward.
AFTER

6. Then continue at home, using anti-static precautions.
7. Remove soft plastic dust-shield (be careful, it's lubricated)
TOP SIDE OF ASSY

8. Remove 2 small screws and detach printed card board (PCB) from it's plastic chassis.
BOTTOM SIDE OF ASSY

Don't lose or break transparent acrylic lightguide (for illuminating PRND) at top plastic piece.

link to hi-res pics, sorry some of them are blurry (phone pictures)
http://picasaweb.google.com/a137bc/SRT8#5400587119203265090
 
#64 ·
Thank you very much for putting this info out there!!! Question

The PCB boards (Your pictures i copied) are they under the the Black plactic Chassi?


This image has been resized. Click this bar to view the full image. The original image is sized %1%2 and weights %3.

These are lamelles before cleaning
This image has been resized. Click this bar to view the full image. The original image is sized %1%2 and weights %3.

After cleaning
This image has been resized. Click this bar to view the full image. The original image is sized %1%2 and weights %3.

Contacts are different - gold plated for gear position and nickel plated for autostick
 
#18 ·
i wonder if i need to do this because i just got a new tranny installed by the dealership bout a month ago,does the shifter assmy come with the new tranny or did they use the old one.cause my warranty is gone now. mine is a 06 with 75k miles an even after the new tranny sumtimes it still takes that spilt second to go in R sometimes idk maybe its just me.would that have to do with the shifter assmy barely having contact or something?



brandon
 
#20 ·
It shocks me also that these things are so horrifically cheap... just IR LEDs would have worked *forever* and cost about $2 more.

Note that this is an MB part and is made by cherry! I would have expected better from both, although the MB electrical gremlins are becoming legendary at this point also
 
#22 · (Edited)
This is great news. I am having problems with the SLA or ESM and got the UBD U0404 code on my '07 Jeep Grand Cherokee Laredo. It drops out of gear on acceleration, all gear lights turn on, and when you let the RPMs drop back down it slams into gear pretty hard. Interestingly we are at right about 35,000 miles! I'm trying to avoid going to the jeep/chrysler service department because they want to run diagnostics, parts and service even though I suggested it was the ESM. We are out of warranty so I'm really wanting a DIY solution. Has anyone had any good results with fixing a similar problem by cleaning the SLA per these instructions?

How do we go about pleading for a recall on these things? I've READ of it mentioned many times but it seems nobody has actually gone through with making the formal complaint.
 
#23 ·
Haha this is exactly what I was going to do to mine. 18K on the ODO I bought a new one and was going to take the old one apart to check it out but have been too buzy. Ya beat me to it. Now I will have a spare one to throw in when I clean it up.
 
#24 · (Edited)
there are some
Older type for 5 gear auto ML-320 and e320
with different shift pattern


And similar to ours for S Class with additional switch for winter/summer

Newer 2005+ Benz cars have 7-speed.

http://www.koperformance.com/online..._text=Floor Shifter Assembly&cat_log=12887425

It's described as genuine Mercedes unit.

I don't know about mechanical fitments issues, donor module is definitely needed.
Although it looks like quite similar we can not change just printed card board with electronics because of different shift pattern.
As far as shift pattern is concerned (it's D-4-3-2-1) it may be differences in CAN bus PIDs also, so new matching TCM may be required (however I'm not sure)

If all above is solved, don't see big problems in rewiring SLA electric socket, even if Mercedes unit has rear gear switch inside SLA, we won't use it, all we need are "can bus +", "can bus -" , +12 V, ground and may be illumination.

As far as I know in Europe Mercedes incorporate anti-theft features in SLA unit, shift from Park is not allowed, if immobilizer unit didn't recognize valid key (even if the key mechanically fits (cut)).
 
#25 ·
I just got the same problem this week with the ESM- Take off from stop or red light and I get no response from engine and all gears are hilighted on the dash. Shift into neutral and back in Drive and then I'm good. CE light comes on sometimes and I'm getting u0404 and p0700. All symptoms are pointing to the ESM being bad. Anyone know the actual mopar part# on this?
 
#26 ·
Brilliant! Saved me 700 dollars. Was getting a U0404 code and performance issues and this after having the ESM replaced 14 months ago. Took about 12 minutes to remove it, and 20 to clean and reassemble(Was flthy by the way). Undid the battery , reset the computer started up and whalla no issues, been 3 days now and no more CEL......no more freaky tranny behavior.
 
#27 ·
I've had mine replaced twice. I have an '07 with over 43,000 miles on it with ab extended warranty. First time it gave me a problem was at aroung 28,000 miles. It started boxing all the positions on the IP gear indicator and going into limp mode, but would clear as soon as I shifted into neutral then back to drive. Sometimes the check engine light would come on, sometimes not. After 3 starts with no failures, the check engine light would go out. This went on for several weeks and hard failed in limp mode before I could get it to the dealer. Had to have it towed in. They replaced the ESM and it worked fine.

Most recently, it started acting up again intermittently, but I had a loud ticking noise that was getting worse as the days passed, so I got it in before the ESM got too bad. I got a new set of lifters and a new ESM and it works like a champ again. Still runs as hard as day 1. Besides tires and a sunroof adjustment, these are the only problems Iv'e had with mine.

Eric
 
#28 ·
Planning to do this tomorrow morning on my 06. I bought contact cleaner at Radio Shack today but, not sure how to actually clean the contacts. Do I just spray it and wipe gently with a paper towel or, just spray and that's it? I don't want to mess up th electronics....

Also, when I'm out in my garage, what kinds of anti-static precautions can I take besides touching ground a few times on the truck before touching the electronics?

Thanks!!
 
#29 ·
To clean contacts you need both soft rag or paper towel or cotton swabs. Just spray a bit at printed card and wipe it gently by moisten rag if you want.
All you need to clean non-conductive (green) spaces between black conductive paths.

Inside jeep static is not an issue, however if you decide to disassemble module on a table and your environment is dry and your floor is made from plastic or covered by synthetic upholstery, touch grounded metal - just for the sake.
 
#31 · (Edited)
agree, even the solenoid is CANbus controlled cutting it out should work.
How is your project going?
By the way - one more area for improvement is Throttle body, Siemens produces Hall sensor based units for Mercedes and resistance based units for our rigs. As I remember BlownWJ has disassembled throttle body, look at his famous thread.

That explains why Chrysler cautions not to spray TB cleaners when servicing TB. Cleaner gets inside the TB sensors area and contaminates (changes the resistance of) conductive paths, which leads to rough idle.
I ignored that caution once and sprayed a few good dozens of cleaner. Immediately I got rough idle issue. It took almost two moths until conductive paths self-cleaned.
However I'm sure even if dealer says replace TB due to rough idle it' possible to open it and clean in the same way as ESM.
 
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