[Miguel924]

Hello.
Maybe someone can figure out what's hapenning to my gearbox. My car is a 99 E430 with the 722.6 automatic gearbox. When the gearbox shifts from 2 to 3 and 3 to 4 I can feel a pull forward like if someone hit my car from the back. It only happens when shifting those gears. 1 to 2 and 4 to 5 are perfect. The bump is more noticiable the more I have pressed the gas pedal.
What could be the problem?
Greetings from Spain.

 

[Kajtek1]

No matter what can be the problem, you need to start with basics.
ATF drain (your converter should have drain plug), new pilot bushing and checking TCU for fluid contamination.

 

[mrboca]

Hello.
Maybe someone can figure out what's hapenning to my gearbox. My car is a 99 E430 with the 722.6 automatic gearbox. When the gearbox shifts from 2 to 3 and 3 to 4 I can feel a pull forward like if someone hit my car from the back. It only happens when shifting those gears. 1 to 2 and 4 to 5 are perfect. The bump is more noticiable the more I have pressed the gas pedal.
What could be the problem?
Greetings from Spain.

Check the ATF level and filter.

--​	Engine revs up during 2 3 shift and /or has harsh downshift during 3 2 shift.​	ATF level in transmission AFT oil filter Free-wheeling unit (F2) Check ATF level in transmission or fill to correct level.​	See 13/8 See document AR27.00-P-0101A​
--​	Shudder in 2 3 power upshift or 3 2 downshift (engine braking)​	ATF level in transmission AFT oil filter Command or Regulating, Shift Control Valves Clutch K3 Check ATF level in transmission or fill to correct level.​	See 13/9 See document AR27.00-P-0101A​

 

[Deplore]

How many miles? Could be worn valve body.

Sonnax has rebuild kit that fixes the bump.

 

[MAVA]

Hello.
Maybe someone can figure out what's hapenning to my gearbox. My car is a 99 E430 with the 722.6 automatic gearbox. When the gearbox shifts from 2 to 3 and 3 to 4 I can feel a pull forward like if someone hit my car from the back. It only happens when shifting those gears. 1 to 2 and 4 to 5 are perfect. The bump is more noticiable the more I have pressed the gas pedal.
What could be the problem?
Greetings from Spain.

Buen dia Miguel,

The only low-cost option for you is to replace the regulation spring and the 2/3 overlap valve and 3/4 overlap valve. Mercedes did have problems with the Free-Wheel units (this transmission has two-One near the front, and one near the back)which is Called a "Sprag Bearing"(One-direction) bearing as they were slipping. mercedes up'ed the count of individual bearings in the part, yet to fix that you will need to drop the transmission and open up the transmission. The spring and valves are available from Sonnax, yet you may find them on ebay too...

Regulating Pressure Control Valve Spring - 68942-01

The Mercedes 722.6 transmission is susceptible to a variety of drivability complaints, such as a delayed engagement into Drive or Reverse. These units can al

www.sonnax.com

2-3 Overlap Control Sleeve Kit - 68942-03

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

3-4 Overlap Control Sleeve Kit - 68942-04

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

All three of them...

Master Overlap Control Valve Sleeve Kit - 68942-05K

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

Best of luck,

Martin

 

[Miguel924]

Check the ATF level and filter.

--​	Engine revs up during 2 3 shift and /or has harsh downshift during 3 2 shift.​	ATF level in transmission AFT oil filter Free-wheeling unit (F2) Check ATF level in transmission or fill to correct level.​	See 13/8 See document AR27.00-P-0101A​
--​	Shudder in 2 3 power upshift or 3 2 downshift (engine braking)​	ATF level in transmission AFT oil filter Command or Regulating, Shift Control Valves Clutch K3 Check ATF level in transmission or fill to correct level.​	See 13/9 See document AR27.00-P-0101A​

No matter what can be the problem, you need to start with basics.
ATF drain (your converter should have drain plug), new pilot bushing and checking TCU for fluid contamination.

Hi.
Yes, I have already replaced the fluid and filter but noo difference.
There is no fluid in the TCM. Everything's good.

 

[Miguel924]

How many miles? Could be worn valve body.

Sonnax has rebuild kit that fixes the bump.

My car has 184000km (114000 miles).
Thanks.

 

[Miguel924]

Buen dia Miguel,

The only low-cost option for you is to replace the regulation spring and the 2/3 overlap valve and 3/4 overlap valve. Mercedes did have problems with the Free-Wheel units (this transmission has two-One near the front, and one near the back)which is Called a "Sprag Bearing"(One-direction) bearing as they were slipping. mercedes up'ed the count of individual bearings in the part, yet to fix that you will need to drop the transmission and open up the transmission. The spring and valves are available from Sonnax, yet you may find them on ebay too...

Regulating Pressure Control Valve Spring - 68942-01

The Mercedes 722.6 transmission is susceptible to a variety of drivability complaints, such as a delayed engagement into Drive or Reverse. These units can al

www.sonnax.com

2-3 Overlap Control Sleeve Kit - 68942-03

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

3-4 Overlap Control Sleeve Kit - 68942-04

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

All three of them...

Master Overlap Control Valve Sleeve Kit - 68942-05K

Continuous plunger valve oscillation causes wear at the overlap control valve sleeves, allowing modulated oil pressure to exhaust or oppose the shift and cre

www.sonnax.com

Best of luck,

Martin

Hi Martin.
Someone told me about that spring too. The spring can be replaced without dropping the transmission, just removing the transmission oil pan and conductor plate. Do you know if those valves can be replaced that way? Removing the complete transmission is too much work for me.

 

[Miguel924]

PROBLEM SOLVED.
Just to let pople know in case they are suffering the same problem. I replaced the following parts:
Conductor plate, Torque converter solenoid, control sleeve kit by Sonnax, control pressure spring (not sure if this was the name of it, but it's the one that usually breaks. Even though in my car it was intact), and electric plug. Apart from that a good clean to the valve body disassembling all valves. Finally an adaptation using xentry.
The car shifts perfectly smooth now as it was doing before the problem appeared.

Thank you to all benzworld members that gave me advice.