94 e420 Transmission Slip When Cold

[Brianarb]

Hi,

Long-time Mercedes owner but new to this forum. Don't know if anyone has encountered this issue before with their vehicle. My car is a '94 e420 with 102k on odometer. Seems that the default answer is often a new transmission. However, recently, when it is cold outside (i.e., 30 or so degrees), the car will have a slight slip into 4th gear. Once the car is warm, the vehicle will shift fine without a slip into 4th gear. Fluid looks clear and red. Seems that the shift quality of the vehicle sometimes differs as well. It will sometimes shift soft and sometimes the shifts are firm. Odd thing is that when the temperatures are above freezing, the problem does not appear.

Thinking of less expensive things to test first, I am planning on a fluid and filter change but wonder if the vacuum modulator could be acting up. I am in Delaware and have not found many decent mechanics in this area who know how to really diagnose these types of cars.

I am used to readily seeing the vacuum lines for the modulator based upon having owned Mercedes diesels in the past but am not familiar with the layout of this model. Any thoughts?

Thanks,
Brian

 

[gerryvz]

Has your transmission fluid been changed since you've had the car?

If you don't know that it has, I would get some of the Red Line D4 or other quality Dexron II or III fluid and a new filter, and change it out (including the torque converter). Jono recommends B&M Trick Shift Synthetic, which he says can solve some moderate issues/prolong the life of a transmission that otherwise would need some work.

You should baseline it with a fluid and filter change first, to see if that helps. The modulator is adjustable (as is the bowden cable) to adjust shift roughness and shift points, but I would take those as second steps, after a fluid/filter change with a QUALITY fluid and Mann or OE MB transmission filter. The modulator has a little thumbwheel that you pull out, turn, and push back in. You NEVER want to turn it more than 1 or 2 clicks at a time. Also it's a good idea to make sure that you have good quality vacuum going to the transmission from the intake manifold. Generally if you don't, you know it because the car will SLAM into gear.

Just so you know, I have had a very similar issue with my 560SEC (which uses a VERY similar variant of the 722.3 transmission as the 400E and 500E) for probably 6-7 years that I can remember. When the weather gets cold, I start the car and run it.... for example going to work in the morning. It's fine at first, then gets a little cranky after about a 1/2 mile and is just a slight bit hesitant to upshift into 4th gear. Not enough to alarm me, but just a little sticky. And if I'm going at a good clip, say above 40 MPH, the transmission will give a slight slip/jolt up into 4th gear. Sort of a slight booster rocket. It only does it once, and after that point the transmission behaves impeccably. And it only does this when it's cold out (45F or below) and only when the car has been sitting overnight or for at least 8 hours in 40s F temps. A fluid change about 25,000 miles ago with "regular" Dexron III fluid and filter didn't result in any change. It's never bothered/alarmed me too much, but I've noticed it again in the past few weeks as we've hit winter weather here in Texas. It's never changed or gotten worse, either. Anyway, I'm going to go the B&M and filter route with my next transmission fluid change, which should be coming up quite soon. My transmission is pushing 207,000 miles, so it will need a rebuild at any point now.

As far as the shifts being soft and firm -- sometimes that's a characteristic of the 722.3 transmission, and can depend on the throttle and adjustments at the Bowden cable as well as the modulator. You can definitely adjust things to soften up or firm up shifts to a goodly degree, but it's a bit of an art to do this well.

GSXR and Jono can provide a LOT more information than me on this, but I'll bet their first advice will be same as mine -- to give it a quality fluid/filter change to baseline things out and see if that makes a tangible difference.

Cheers,
Gerry

P.S. By the way ....

 

[Brianarb]

Gerry,

Thank you for the reply. I have owned the car for about 1 year and, unfortunately, did not get around yet to changing the fluid. Previous owner was a mechanic and seemed to be o.k. at keeping up with the basic maintenance. Spent the past year sorting out issues with the camshaft oiler tubes, exhaust, the suspension and a sticky monowiper, etc. A bit on the fence about selling it right now, too, to keep harmony in the household, if you know what I mean. However, I think that a fluid change is in order.

Best,
Brian

Has your transmission fluid been changed since you've had the car?

If you don't know that it has, I would get some of the Red Line D4 or other quality Dexron II or III fluid and a new filter, and change it out (including the torque converter). Jono recommends B&M Trick Shift Synthetic, which he says can solve some moderate issues/prolong the life of a transmission that otherwise would need some work.

You should baseline it with a fluid and filter change first, to see if that helps. The modulator is adjustable (as is the bowden cable) to adjust shift roughness and shift points, but I would take those as second steps, after a fluid/filter change with a QUALITY fluid and Mann or OE MB transmission filter. The modulator has a little thumbwheel that you pull out, turn, and push back in. You NEVER want to turn it more than 1 or 2 clicks at a time. Also it's a good idea to make sure that you have good quality vacuum going to the transmission from the intake manifold. Generally if you don't, you know it because the car will SLAM into gear.

Just so you know, I have had a very similar issue with my 560SEC (which uses a VERY similar variant of the 722.3 transmission as the 400E and 500E) for probably 6-7 years that I can remember. When the weather gets cold, I start the car and run it.... for example going to work in the morning. It's fine at first, then gets a little cranky after about a 1/2 mile and is just a slight bit hesitant to upshift into 4th gear. Not enough to alarm me, but just a little sticky. And if I'm going at a good clip, say above 40 MPH, the transmission will give a slight slip/jolt up into 4th gear. Sort of a slight booster rocket. It only does it once, and after that point the transmission behaves impeccably. And it only does this when it's cold out (45F or below) and only when the car has been sitting overnight or for at least 8 hours in 40s F temps. A fluid change about 25,000 miles ago with "regular" Dexron III fluid and filter didn't result in any change. It's never bothered/alarmed me too much, but I've noticed it again in the past few weeks as we've hit winter weather here in Texas. It's never changed or gotten worse, either. Anyway, I'm going to go the B&M and filter route with my next transmission fluid change, which should be coming up quite soon. My transmission is pushing 207,000 miles, so it will need a rebuild at any point now.

As far as the shifts being soft and firm -- sometimes that's a characteristic of the 722.3 transmission, and can depend on the throttle and adjustments at the Bowden cable as well as the modulator. You can definitely adjust things to soften up or firm up shifts to a goodly degree, but it's a bit of an art to do this well.

GSXR and Jono can provide a LOT more information than me on this, but I'll bet their first advice will be same as mine -- to give it a quality fluid/filter change to baseline things out and see if that makes a tangible difference.

Cheers,
Gerry

P.S. By the way ....

 

[gerryvz]

Let us know whether changing the fluid/filter makes a difference in the shift quality. Like I said, invest in a high-quality transmission fluid if at all possible. Since it should be good for at least 20K if not 30K miles, in the overall swing of things not a bad investment. Make sure you drain the old fluid from the torque converter (and lines, if possible) too !!

Cheers,
Gerry

 

[Trae]

My transmission shifts like new after using Redline D4. Two gallons.

 

[gerryvz]

My transmission shifts like new after using Redline D4. Two gallons.

 

[Aston Martin]

Garry,

I have the same problem, my car when cold wont shift to the 4th from first time, so I will change the oil to Dexron II or III,
in Dubai there is no Red Line D4, what do you recommend as a good quality Dexron oil other than RedLine?

 

[samiam44]

Redline is a US synthetic fluid... Choose a Dextron III or IV fluid which is synthetic- not sure what you have available in the UAE. I'm sure there are lots of good fluids from Europe. Christian can give comments whom is in Germany?


Michael

 

[gerryvz]

Any Dexron III rated fluid would be fine, whether synthetic or traditional. I am running cheap Dexron III fluid in my transmission and will be changing it out for RedLine Hi Temp in the future. Don't use Dexron II, go with something that is Dex III rated.

You can order the Red Line fluids through Amazon.com, though there are other brands of traditional and synthetics that should be available through local sources in Dubai.

Cheers,
Gerry

 

[gsxr]

Dexron II or III is ok. Mobil-1 ATF is acceptable if you can buy that locally, also Amsoil ATF.

DO NOT use Dexron-VI rated fluid, it is thinner viscosity.

Make sure the fluid level is near the "Max" mark when the transmission is fully hot (i.e., after driving 20+ minutes at freeway speeds). Check the level with the car idling in Park, on a level surface.

 

[Aston Martin]

Thanks guys,

I will replace the transmission oil hopefully it will solve the issue, however do I have to use original transmissin oil filter or any aftermarket will be fine?
Replacing the oil including the torque converter dose that require special procedure or normal oil drainage prosess is satisfactory?

 

[gerryvz]

There is a full HOW-TO on replacing transmission fluid at this link: http://www.500eboard.com/forums/showthread.php?640-722-3-transmission-oil-change-instructions

Also ... more info here: http://www.500eboard.com/forums/sho...ctant-to-upshift&p=39049&viewfull=1#post39049

Go with a factory filter -- it is specific to the 500E and a couple of other models. They are not all that expensive if purchased through a source like parts.com. There are a couple of good aftermarket brands as well, but you should really get the filter that is specified for the 500E/E500 application ... not the one for "normal" 722.3 transmissions.

To do the job right, you will also need to drain the torque converter. It has a separate drain plug and draining procedure.

Again, complete information & details are at the link above.

Cheers,
Gerry

 

[gsxr]

Aftermarket filters from Mann or Elring are fine, and are much cheaper than OE (like, 1/2 to 1/4 as much as parts.com).

Torque converter MUST be drained, this is not optional.

As Gerry said, it's all in the link he posted above...

 

[Aston Martin]

thanks for the information,
I found Dexron III german brand oil.

gsxr, what about febi bilistein transmission oil filter is it good for the 500E ?

 

[gsxr]

Febi-bilistein transmission filter would not be my first choice, but if you can't get OE, Mann, or Elring... it should be ok.

The correct filter for the 500E has dual inlet ports as shown below on the right, make sure you get the correct filter.

 

[Aston Martin]

How many Litter fluid 500E transmission require in total including torque converter

 

[gerryvz]

7.9-8 quarts.

 

[Aston Martin]

Thanks Gerry, that's 7.5 litter.

I will keep you updated.

 

[Aston Martin]

An update after changing the oil to Dexron III, the shifting is much more smooth than befor especially when hot however when first drive in morning the transmition shift from 2nd to 3rd normally but from 3rd doesn't shift to 4th it's become neutral only the firt time then it become normal.

 

[gerryvz]

Does your car have the upshift delay when the car is cold? By where it holds gear longer when coolant is below a certain temp, to warm up the engine/cat a bit faster?

 

[Aston Martin]

One more thing today I have tested the car under full power up to 220 Km then I smell transmission clutch , and there was some power missing for less than a second in a deferent speed and rpm, for info the sparks, rotors and the sparks cable all new.

 

[Aston Martin]

Does your car have the upshift delay when the car is cold? By where it holds gear longer when coolant is below a certain temp, to warm up the engine/cat a bit faster?

maybe not sure, the RPM reach to 3000 to shift to 4th but you can control the shifting by loosen the throttle.

 

[KarlC]

Does your car have the upshift delay when the car is cold? By where it holds gear longer when coolant is below a certain temp, to warm up the engine/cat a bit faster?

Is this normal, should all 500E / E500 do this cold up shift delay, if so whats it for ??

 

[Glen]

Is this normal, should all 500E / E500 do this cold up shift delay, if so whats it for ??

Yes and yes. It's supposed to help the catalytic converters warm up more quickly.

 

[Christian_K]

One more thing today I have tested the car under full power up to 220 Km then I smell transmission clutch , and there was some power missing for less than a second in a deferent speed and rpm, for info the sparks, rotors and the sparks cable all new.

Raise modulating pressure ASAP. Buy a new cover plastic-cap for the modulating-pressure actuator, pry the old one off (it will probably brake), pull "T" shaped piece and turn it 1/2 turn (180°) (clockwise or counterclockwise - forgot it), push it back in and push new cover plastic-cap on.
Then testdrive.

 

[Johnnybenz500e]

Hey Gerry ,

just a quick question, is oringial MB transmission fluid also good to solve minor trans problem like the ones stated above? Or is this red line product you talk of a miracle fluid? Is it only made for problem transmissions or is it also used as your every time change?

Thanks

john

 

[gerryvz]

New fluid can solve a myriad of ills when it comes to misbehaving transmissions, but it is not a cure-all by any means if there are worn friction or other components inside of the gearbox.

Any Dex III spec fluid should be fine as long as it is used with a new filter, and ALL of the fluid is drained (i.e. the torque converter and the pan). Personally I use regular non-synthetic Dex III Castrol Transmax fluid in all of my cars, and I will change it after 20-25K miles.

The RedLine full-synthetic D4 ATF is a top of the line fluid, no question. It's expensive enough that I'd only use it on a properly operating box ... I would not use it to try to "fix" a misbehaving transmission.

There are some fluids, such as B&M Trick Shift, that can improve shifting behavior and perhaps go some of the way in solving moderate transmission shifting problems, because they contain friction modifiers that enhance the lubricative properties of the transmission fluid and can enhance shifting and/or reduce flaring. But honestly, these fluids are largely Band-Aids for deeper problems ... perhaps putting of a proper transmission rebuild by a certain amount of time or mileage?

A quality synthetic or "restorative" ATF isn't going to solve the reverse clutch issues that the E500E transmissions commonly face, for example. Not gonna happen.

GSXR and Jono are the transmission experts, so they can provide better advice on ATF. I had a situation last year whereby my car (which probably had 40K on the ATF) suddenly became reluctant to upshift, and numerous folks here immediately said to change the fluid and filter. I did so and it immediately solved the problem. I then and baselined the ATF on two of my other cars, both of which had 20-30K on the ATF.

Hope this helps. Bottom line is that I wouldn't invest in the $100+ for top quality RedLine synthetic ATF unless my transmission was in peak health. My E500's is not ... I have moderate reverse clicking, which precipitates a rebuild at some point in the future. After that rebuild, if everything checks out OK, I'll definitely use the RedLine ATF.


Cheers,
Gerry

 

[gsxr]

Ditto what Gerry said. If the fluid is not recent, change with any Dexron-III fluid. The OE MB fluid isn't a magic bullet. And I wouldn't shell out for Red Line or other synthetic unless the tranny was working correctly - synthetic most likely won't cure shift problems.

If you have shift issues with flaring, that are not cured with new fluid, modulator pressure adjustments, Superior spring kit (for specific shifts), etc... there are a couple of "last resort" efforts you could try prior to shelling out for a rebuilt box. But it's best to try the usual stuff first before going to more extreme measures.

For the record, I have Red Line in my "good" transmissions, but I use cheap fluid in any box that isn't working right, until I can get it working right.

BTW - welcome to the forum, John!

 

[Johnnybenz500e]

Thank you for the welcome I'll post high resolution pictures soon of my 92.. 143k pearl black/ parchment

 

[clarkz71]

Ditto what Gerry said. If the fluid is not recent, change with any Dexron-III fluid.

Oh, transmission fluid. My favorite topic______