Hi there,

I own a 99 XKR which has 156000km (97k miles) and i was about to change the gearbox oil of the MB 722.6 mounted on this model. I bought everything related to that oil change (oil, oil filter...) and was about to do it but when i first put the 5€ ebay dipstick to check the current oil level i noticed a much too high level.

The car was cold and not running when i checked the level, i just started it to get it out of the garage and it ran for about 5 minutes and sat for 30 minutes before i checked the oil. The oil level was higher than the max level of the "Hot" area (85°C) wheras i was expecting it to be around the max of the "cold" area (25°C) on the dipstick.

Of course, having bought that dipstick from ebay i'm not sure if it's correctly calibrated (it's way too long anyway) so i'm not sure of the actual gearbox oil level. The gearbox is working normally, i'm planning the oil change as preventive maintenance.

The other surprise (a good one this time) was that the gearbox oil has been already changed apparently (the conduit to the gearbox was not sealed y a red plastic cap, just a black MB cap) and the oil is clear, looks golden on a white piece of paper and the smell is... well it smells like fresh oil, not burnt or any bad smell. I was surprised because there is no mention about any gearbox oil change in the service history.

My Questions :

How do you correctly check the gearbox oil level? The car must be running or not ?
Is the ebay dipstick level reliable ? I bought this one : https://www.ebay.fr/itm/323727488321
Is there any procedure i can do to check the level reliably ?

Thanks for your help !

 

Hi Ryan, may we assume "gearbox" oil means transmission fluid?

If so we need to synch up. None of these cars XK8 and/or XKR came with a dipstick or any external access to check transmission fluid.

If you have an XK8 or XKR and it has a transmission fluid dip stick, someone added it after market. That's not bad, but you do not know its accuracy and can not use it to measure the refill.

Here's an idea. Mark the fluids position hot before you do the job.

When you drop the pan and collect the old fluid, consolidate it and measure how many liters was there.

Replace the filter and pan, start to refill. The instructions are very specific. Double check me but as I recall: fill to the top of the pan's drain. Warm up car.

Get the transmission fluid to a specific temperature. This number is in the instructions. Once temperature is reached, cycle the transmission through all forward and reverse gears. Put in park, fill the fluid to where it just starts dripping out.

Now you will know you have exactly the right amount of fluid in her. Seal the drain plug.

Ryan you may have an advantage in that you could do the final top off using the access from the drip stick tube. Just have someone underneath to say stop when shes full. It's a real tough job to add that fluid to the drain hole, maybe you have an edge.

Now you have a full tranny, adjust the full mark on your stick. I suppose the previous full mark is no more than interesting/anecdotal at this point. But I'd sure be interested to see if the amount removed equals the new amount added.

John

 

4L XKRs have a Mercedes 722.6 aka W5A580 transmission. They do come with a dipstick tube, but not the dipstick itself. You buy these really long universal ones (universal by design by Mercedes) and that is what you use to check fluid. Most of the trans dipsticks have a flimsy plastic piece at the end with the levels; and that can lead to confusion on levels. The advice on gear shifting, measure old, etc, that can help.

This guide should be really helpful: https://www.pelicanparts.com/techart...uid_Change.htm

Note - Some years and configurations of 722.6 do NOT have torque converter drain plugs; if you do have one, use it, if not, move along . Absolutely do the connector, they're like $10-15. I use a temperature gun that was $20 and used it alongside several hundred dollar calibrated fluke ones and it's definitely well within the acceptable range of accuracy for the job (usually within a degree or 2 fahrenheit, this stuff is Celsius on the dipstick and the instructions for the record); you can find a lot of these infrared pyrometers cheap on amazon.

 

That looks identical to the one I bought - its far longer than needed on the XKR, so just insert it until you feel it touch the bottom of the pan. The procedure is in the workshop manual - you should find that and read it before doing anything else.

If I were you, I would drain the existing oil out of the pan, then re-fill with fresh oil (I used Fuchs Titan ATF 4134) following the correct procedure in the manual, being sure not to overfill it. On mine (not being able to drain the torque converter) it took about 4 litres to refill. Don't forget to buy replacement copper washers for the drain plug.

 

Thanks for the advice, I agree with the dipstick / tube it came with just a tube but it's supposed to be sealed by some red plastic thing that i don't have, that's why i'm guessing (also with the fact that the oil i got from the dipstick was clear and not 156k km old) that the job has already been done, but i have no idea when. That's why i'm confused about the oil level, if someone changed it (and without any mention on service records) then the level might be wrong, or is it the case with everyone using that dipstick ?

In the page you mentioned they say : "The 722.6xx transmission fluid level is critical, three to four ounces plus or minus and it will not function correctly" mine is working normally for thousands of kilometers now so i'm mostly blaming the dipstick or maybe i'm pushing it too hard and it bends i don't know.


I have a draining plug on my 722.6 i can see it from underneath the car even though i never used it yet (why put a drain plug if it's lifetime sealed then Mercedes huh?) but i don't know if i have the torque converter draining plug yet.
What connector are you talking about? i only bough a MANN filter and gasket and 8L of Fuchs Titan ATF 4134 and have spare copper rings for the drain plug if needed.

 

That's what i did, it's far too long but it reaches the bottom of the pan and shows a very high level, was it the cas with yours too ? I mean if it is too high and i put the same amount back i'm going to have the same problem, with fresh transmission fluid but still too much of it. I'd love to check the workshop manual but i don't have it; maybe you have a link to it somewhere? Thanks

 

Hi John, as others said the XKR and XK8 4L have different transmissions, the one on the xkr came with a drain plug and a level / fill tube. I'm already familiar with the procedure (i flush all automatic transmission fluids on my cars) but the problem is that i'm not sure of the current level : is it right and the dipstick is wrong (aftermarket chinese 5€ plastic thing) or does my transmission have too much oil in it due to (i presume and i have clues to say so) a precedent transmission fluid replacement, maybe they've put too much in it.

If i apply the procedure and put back the same level of ATF, i'm going to put too much oil in it too so that's my concern and why i need to find out if my current ATF level is ok or not.

 

the dipstick I purchased is the correct one. The length of the dipstick is not important, other than it must be long enough to hit bottom. I haven't seen one yet that was too short.

What is important is that you insert it FULLY so it hits bottom. The best way to be sure of this is to insert the dipstick until it feels to have bottomed out, then drop the pan and visually confirm that it indeed was making contact with the pan. ( ... you were going to drop the pan anyway so you can replace the filter, right ?

The marks are calibrated from the bottom up. If your purchase is for the Mercedes 722.6 transmission, and from a reputable seller, such as Pelican Parts, then you will be OK.

https://www.pelicanparts.com/More_In...=0&SVSVSI=4092

Z

insert the dipstick until you see it reach the

 

@Zray : The dipstick you mentionned from Pelicanparts is the one i have and it is reaching the bottom, i can feel it and the fact that the level is too high implies that not only i've reached the bottom but that it's maybe plying a little.

 

No.

There is no space for it to flex enough to make a difference in the reading. The dipstick tube is not large enough in diameter for that to happen. If your observing a level that is too high on the dipstick, with the transmission temp at or close to the 85 C temp mark, then the only answer is that someone has OVERFILLED the transmission. I would suggest that you use a OBD-II reader to display the actual temp of the transmission fluid instead of a IR gun. When using the OBD-II information, be sure to have the transmission in drive or reverse when accessing the reading on the meter. If you have the car in Park or Neutral, you will be seeing the engine coolant temp, not the transmission fluid temp, despite what the meter is saying. There is a service bulletin covering this subject.

Z

 

Mine showed the correct oil level (actually slightly under as there was a leak from the connector sleeve). This sleeve is the connector mentioned above - if you are draining the gearbox you may as well change the sleeve as the gaskets eventually fail and leak.

The workshop manual is available as a PDF download somewhere - someone might have a link.

 

Is that it ? https://www.dropbox.com/sh/mkchxc77m...PEiFn8_aTP2Tga

 

I've checked this week-end the transmission fluid level again with the car sitting for at least two days so the gearbox is cold as can be and the read level is above the the "max" of the 80° line.

Also the red plastic cap that you have to break to access the tube isn't there and the transmission oil seems rather new, not brand new of course but definitly not 20 years and 160000km old so it has been changed previously and probably the previous owner or the one that serviced it put too much oil in it.

Other than that, the gearbox is working normally. What do you recommend? Change the transmission fluid with the correct level or leave it as it is ? Maybe it has been overfilled for a reason (prevent slipping for instance) ? I don't know if it makes sense.

 

There is no good reason for driving the car with an overfilled transmission. Overfilling won't help any problem get better by itself. Your best bet is to drain all the fluid you can and refill to the 85 C mark.

The fluid you use must be from the list for the high performance 722.6 Mercedes transmission. There are many 722.6 transmissions in use that are using a fluid not recommended for your high performance transmission. This has been covered in numerous topics recently. If you can't find the list , just ask and I'll post it again.


Z

 

+1 to Zray,

Yeah, I agree whole heartedly with Zray. Although I do not have the Merc 722.6 gearbox, there are known problems with overfilling any automatic gearboxes - ie slipping gears. You may not have any gear slippage problems now, but overfilling causes fluid foaming which will exacerbate ATF heating and prematurely age your good ATF so it loses its lubricating powers faster.

Besides, you've no records of when the ATF was last changed so doing it now is as good as time as any. Broken gear boxes are typically a reason to scrap our low value cars as it's just not worth replacing it - in a purely financial viewpoint.

 

Just a few points to touch base on:

1. The dipstick has "stop ears" at about 80mm from the tip, and the tip is not supposed to touch the bottom of the pan. (There is some factory literature that reads that the tip does touch the pan which is in error.)
2. If your dipstick "stop ears" are not wide enough, your dipstick will pass beyond the stop ring and bottom on the pan which will add in error about 3/4" of oil depth to your dipstick reading.
3. If you are pinging the pan for an IR temperature reading, add 10 Deg F to that reading. (Per Avos)
4. My dipstick tube has a black cap that had a red lock tab that I removed. I just snap it on and off.

Here is my embarrassing, but informative post from 2012:
https://www.jaguarforums.com/forum/x...warning-78144/
Many thanks to Avos for setting me straight. I did fact check him at the time. (Mercedes Sprinter documentation)

 

no ears on the aftermarket dipsticks, they are universal so they can work with many different cars using the 722.6 transmission. All cars do not have the same dipstick tube length, therefore the aftermarket dipstick do indeed have to touch bottom as that is how the the temp / full marks are calibrated.

I've never seen a factory dipstick tool, so I'm not disputing Dr. D's post at all. Just pointing out that the aftermarket universal 722.6 dipstick doesn't follow the factory rules


Z

 

Z:
The "ears" of the factory Mercedes dipstick (see attachment) are copied by virtually every aftermarket source including Ryan B 's purchase at the beginning of this thread.
https://www.ebay.fr/itm/323727488321
I have had (4) 722.6 trannys with different length dipstick tubes, however the same dipstick works for all of them.
The only time that the dipstick tip will bottom on the pan is if the ears are not wide enough and pass through the stop ring (sleeve). (see 2nd attachment)
To insure that I continue to not bottom on the pan, I check my dipstick by inserting it fully while the pan is removed. (Also see 2nd attachment)

 

We are using the same words to apply to different parts of the dipstick. When I say "ears" , I'm tslkimg about the opposite end of the dipstick than you are referring to.

Nevertheless, my dipstick , which has the same measuring end of the one you posted, ( with "ears" ) will reach the bottom of the oil pan , or within about 1mm of the bottom, which to me is essentially the same thing.

Z

 

Hello Z: I have not done that 1mm measurement, but according to Avos, it is more like 19mm. I would now be curious for someone who has the pan removed (Maybe Ryan B), to measure that difference. I'm thinking that I would use a straight edge, caliper depth gage, and possibly a couple of spacers.