Mercedes 722.504 Rebuild Question

[Walid]

Hello,
I am currently rebuilding my 722.504 transmission.
The car is a 1996 S124 E280.

Does anyone have a previous experience with discs/plates from a reputable brand as a replacement or is OEM a must?

I am also confused about the 722.5xx variants. I found a valve body that turned out to be from a 722.509 has a part number (A124 270 80 15).
However, as per EPC, the two part numbers for my 722.504 are (A124 270 64 15 & A124 270 79 15). Couldn't find anything online about it but are they interchangeable by any chance?

Thanks

[Diesel911]

Few people have done a full transmission rebuild.

The transmission is a ZF transmission. What instructions source are you using?

You might pose the same question over on the diesel discussion section as many that post there seem to do more of their own work.

Another forum is benzworld.org

[Walid]

Originally Posted by Diesel911

Few people have done a full transmission rebuild.

The transmission is a ZF transmission. What instructions source are you using?

You might pose the same question over on the diesel discussion section as many that post there seem to do more of their own work.

Another forum is benzworld.org

I am using ATSG & Transtec/Corteco for information and Mercedes EPC for part numbers.

I have learned that every 722.5xx variant "may" have a different valve body. In my case, I have sourced a transmission out of a W210 E320 that turned out to have bad friction plates so I have decided to fix the original transmission and take the valve body from the donor.
The 722.509 (E320) I found has a different part number from my .504 (E280) however, all internal components of the valve body are identical. Not sure how would this impact my transmission.

[Zulfiqar]

Btw

This is not a ZF transmission, its a mercedes benz transmission and if it tickles your fancy its very close to a GM in design.

That aside, the atsg guide is a good start point, but snap a million pics of parts as you remove them and keep them in order as the arangement of some are unique in every submodel and the only way to get that information is from the factory manuals, none of the automatic transmission chapters were ever translated, there are close to 8 books of it.

Best of luck.

[cth350]

Quality control from some suppliers is basically doo-doo.
You can definitely get OEM from the Mercedes Classic Center.
But also, you can trust a large supply house that has been in business a while.
That depends on where you live and who you can call.

Once you have the parts in hand, you're going to want to visually inspect them and you're going to want to measure thickness of the various plates. Pay careful attention to instructions about how thick the clutch packs should be. Also, pay attention to what constitutes wear and damage to the specific hard parts you are going to be reusing.

As somebody else said, pay careful attention to where things where and have notes about where to put things back, as your own notes will be the only reliable source of information about what you are doing.

Worse case, you'll be doing it all over again with a fresh set of seals. But I doubt you'll to do it more than twice unless you are exceedingly unlucky.

Please share progress with us and when you run into a speed bump, somebody who's been following along may well be able to lend you a hand.

Good luck and remember, the worse that can happen is that it goes wrong. So don't let that stop you from proceeding.

-CTH

[Walid]

Originally Posted by cth350

Quality control from some suppliers is basically doo-doo.
You can definitely get OEM from the Mercedes Classic Center.
But also, you can trust a large supply house that has been in business a while.
That depends on where you live and who you can call.

Once you have the parts in hand, you're going to want to visually inspect them and you're going to want to measure thickness of the various plates. Pay careful attention to instructions about how thick the clutch packs should be. Also, pay attention to what constitutes wear and damage to the specific hard parts you are going to be reusing.

As somebody else said, pay careful attention to where things where and have notes about where to put things back, as your own notes will be the only reliable source of information about what you are doing.

Worse case, you'll be doing it all over again with a fresh set of seals. But I doubt you'll to do it more than twice unless you are exceedingly unlucky.

Please share progress with us and when you run into a speed bump, somebody who's been following along may well be able to lend you a hand.

Good luck and remember, the worse that can happen is that it goes wrong. So don't let that stop you from proceeding.

-CTH

I was actually able to finally put it back together with the help of a friend and the manuals. It works great and shifts into gears smoothly. It was slipping before and had issues due to worn inner discs, outer, brake bands, and seals.

Still, however, 5th is nowhere to be found. I built a code reader using information from a member post and got code for :
- Left rear axle vehicle speed sensor or Hall-effect speed sensor

Before rebuilding I had no 5th gear and the cruise control would drop until it eventually stopped working as well as having an ABS light and the car would stall when at stop or under load at low speed. Y3/1y2 valve tested OK. I will diagnose the speed sensors and throttle body and 4<>5 switch in hopes to find a solution in this maze step by step

I couldn't find the exact valve body match for E280's 722.504 which is 124 270 64 15 / 124 270 79 15, and found one for E320 722.509 which is 124 270 80 15. Although they had the exact part numbers for the internal parts , the valve body assembly number is different. Can you help me understand the difference? And if it would do any harm to use it till I can source the correct one

[rayhennig]

Originally Posted by Walid

Before rebuilding I had no 5th gear

5th is controlled electrically, with a hint of 1980s electronics. It is controlled by the HGS box.

You need to check any error codes returned by the HGS. And, of course, that the HGS is properly plugged. I lost 5th when I installed a used eBay HGS and didn't plug it in properly. After that, I cleaned contacts, cleared error codes and 5th is back.

And so is 4th because that can be an issue.

Generally, problems with 4th/5th are related to the electronics, not the 722.5 gearbox itself.

Also, ensure that the 4th/5th switch is working - in my case, I replaced it for about 20€, built a led blink code device, cleared the code and 4th returned as it should.

Good hunting.

RayH

[Walid]

HGS surprisingly did not give any codes. I wanted to actually test 4<>5 , Did it you get a code when the switch was faulty?
My thought is that the engine stalling at low speed/load has something to do with the intake which I read 5th selection is dependent on. Also, ABS light on + cruise control my guess is that it is due to rear abs sensor / hall effect sensor fault code.

I will test and proceed to provide updates.

[rayhennig]

Yes, it returned a code and 4th was skipped and it went quickly to 5th.

Before I installed a new switch, clearing the code would solve the problem for a short time.

If your ABS light is on, have you thought of changing the OVP relay?

RayH

[Walid]

Originally Posted by rayhennig

Yes, it returned a code and 4th was skipped and it went quickly to 5th.

Before I installed a new switch, clearing the code would solve the problem for a short time.

If your ABS light is on, have you thought of changing the OVP relay?

RayH

Interesting info about the switch. It did not return a code for that. I actually have 4th working fine (100 Kmph @3,100 rpm approx).
Yes, I read about all the troubles it may cause due to bad solder joints on the OVP relay. I am trying to find a used part while testing speed sensors since a new one is not in stock and would require time.

[Walid]

So the intake resonance valve was the reason the car would stutter under light load and rpm fluctuate/stall completely. One issue down!

Tried replacing the shifter and OVP, but no luck. ABS light on, cruise control off, and no 5th gear.
I actually got a new fault 5 on pin 14 for the stop lamp switch AND pin 13 (Transmission) is giving me a solid light now. Just yesterday it was fine and read no codes. Got to go retrace my steps with the shifter and check.

[Walid]

Update:

Finally some good progress! I unplugged the TCM and was able to shift to 5th from 3rd (skipping 4th). At least now I can be assured that the overhaul was successful and that the problem is outside of the transmission.

Will post more for reference to anyone who comes across the same problem.

[rayhennig]

Originally Posted by Walid

Update:

Finally some good progress! I unplugged the TCM and was able to shift to 5th from 3rd (skipping 4th). At least now I can be assured that the overhaul was successful and that the problem is outside of the transmission.

Will post more for reference to anyone who comes across the same problem.

I cleaned the contacts on the TCM and its socket and also I dismantled and cleaned the switches: E/S switch and 4/5 switch.

In my case, I had to clear codes but, thereafter, so far, all is well.

RayH

[Walid]

Am currently adjusting the alignment and SLS on the car since I do not have proper steering control.
Here is an update:

- Car still does not shift to 5th (Unless TCM is removed then it goes 3 -> 5)
- Cruise control still not working
-ABS light continuously on

Tried checking the pins on the ABS control module, which were fine and gave the contacts a clean as well.
What I tried doing was clear all codes, made sure it read no codes, and then started the car. It STILL had ABS light on even without codes. I went for a drive and came back to codes 28 from pin 8 (VSS - open circuit) and code 9 from pin 14 (Left rear axle vehicle speed sensor or Hall-effect speed sensor / Rear axle vehicle speed sensor from ABS control module).
My next step will be to trace the rear axle speed sensor wire to see if it is faulty (sensor itself looks fine and free of debris).

[Walid]

Update:
Back up and running !
Having to source a specific differential mounted speed sensor for a Mercedes from that era sure was challenging and time consuming.

To sum up for anyone who would come across this thread on a similar issue:
I lost my 5th gear on 722.5, ABS system stopped working as well as cruise control.
What happened was the odds all played out at the same time!
Having the inner discs/friction plates on the transmission worn out. After overhauling the box I still had no luck with 5th. Turns out to be an intermittent faulty speed sensor on the differential. Replaced it with a second hand sensor and got cruise control and normal gearbox functionality again !
The sensor should have a resistance reading on the multimeter as well as a voltage reading when moving the wheel, or by cutting its magnetic field if outside the vehicle by any metal piece without actually touching.

Now I still have the ABS light on for some reason. I remember reading somewhere that it might need an emergency stop as a “wake up” to the system. Will test more and report.