its funny my Porsche is exactly the same. Fill it up until it starts overflowing, run the car until the transmission gets to operating temperature, and then frantically try to close the plug while hot fluid runs down your arm... on the Porsche the directions actually have you raise all four wheels off the ground and run the transmission through different gears during the process.. compared to that the gl is easy...

 

I don't know if this is significant in this case, but: It is difficult to get an accurate reading with an infrared thermometer unless it is calibrated to the material you are reading from. For a given temperature, different materials radiate heat at different rates (spectra, for the physics geeks). You can calibrate it on your infrared thermometer; it's called the "emissivity".

Better is a contact thermometer, or access the computer's temperature reading via a tool such as the i980, MBII, Autel, or STAR.

 

a infrared thermometer is the guaranteed way to end up with far less or far more fluid in there. you need to use star/ das and read the fluid temp directly from the temp sensor.

 

Hi Alx,

I agree with everything you said except for the word "far". Transmission Fluid has a coefficient of thermal expansion of roughly 0.0004/°F. So a temperature rise or fall of 10°F will increase or decrease its volume by 0.4%.

So it seems to me as long as you are in the ballpark, almost regardless of how you read the temp, you will end up within an ounce or two of what Mercedes calls for...

i could also argue that with a properly calibrated infrared thermometer, you are more likely to seal up the fill hole at the instant the tranny pan hits the specific mandated temperature - since you are already right there under the truck when you are reading the temp - but that would be arguing against myself that close enough is good enough. 😁

in all cases, we wrenchers are sooo much more likely to try get the levels close to correct than any 3rd party mechanic...

 

Our beloved alx is prone to hyperbole.

However, your thermal expansion spec doesn't seem right. Automatic transmission dipsticks have a pretty wide range from cold to hot. By your numbers, 100F would be 4%, and that range on the dipstick doesn't pass the giggle test for 4%.

Emissivity is very difficult to get right. What's more, you are looking for the emission outside the pan or housing, and there is a temperature differential across it, particularly if you are looking at the steel pan. You would want a flat heat conductive surface painted flat black so you could set the emissivity to a reference figure (~95% in that case). Surface roughness, oxide layers, rust ... ugh. There are so many ways for it to go wrong. Keep in mind the IR thermometer is looking at the shape of the spectrum, doing its best to fit it to a black body radiation curve ... ugh, so many ways to go wrong.

Why don't you hook up your MBII (if you don't already have one, highly recommended) and compare your IR thermometer with the readings the MBII delivers via its nice long cable to you under the car?

 

I have seen a couple 722.9 trannies filled via the infrared thermometer method- they both were very short on fluid- about a quart to be precise. I would not speculate why- just sharing.

 

I used to have a bluetooth ODB2 port plug that would give me this on an AUDI. Any idea if that works for MB? (can't find my old one)

It was this one.


I ordered another.

 

Sadly my BMW doesn't even have a place to check the motor oil level or condition without it running and checking the computer or pulling out the filter. . Dumb

 

You'll want the bluetooth adapter in any event. It's excellent for quick n dirty peeks into what the motor is doing.

The right software on your phone probably could access the trans temp. I didn't find it via Torque Lite, though. I have Torque Pro but haven't installed it; supposedly it reads transmission temp on some vehicles.

 

Just tried it, and Torque Pro does display trans temp on a X164.

 

PUURFECT

 

YEAH BABY

So worth the $5bux for Pro. Toss the developer a bone - it's a great app.

Thanks for checking it for us.

 

I just completed the differentials and transfer case on my 2011 GL 350. I also did the transmission service, but the new transmission pan gasket was dripping a bit, so I need to redo that part again this weekend. I tow a large airstream so I have been doing all of this stuff at 40k mile intervals.

Some new learnings.

The front and rear differentials now call for Mercedes 235.7 or 235.74 spec gear oil. It appears that both Fuchs and Liqui Moly have stopped making a compatible 235.7 product - or at least it's not available in their US distribution channels. I first ordered Liqui Moly through Pelican Parts and their supplier sent oil that was both the wrong weight and not limited slip - but had the same part number as what is listed as 75W-85 MBZ 235.7 compliant oil on the Pelican website. The Pelican folks think their vendor messed up their catalog listings and included the MBZ spec for every 75W-85 product they carry - so buyer beware. I next tried to order the Fuchs product, FUCHS TITAN SINTOPOID FE, which is MBZ spec compatible, but it's listed as being out of stock everywhere I looked, and the Pelican folks also said they could not get it. So I ended up driving to the dealership for three quarts of $35 official Mercedes differential oil. What a racket. Mercedes also no longer offers new o-rings for the differential plugs - they want you to buy two new plugs for $15 each. On principal, I reused the old plugs and have no leaks.

The transfer case calls for good old ATF 134 Automatic Transmission Fluid - the red stuff. It was quite hard to get the configurator on Pelican Parts to show me this product as their system thinks it is incompatible with the GL350 and just wants to show you the blue stuff - 134 FE. I ended up selecting a different vehicle and that allowed me to buy regular ATF 134 - just half a quart is all you need. The transfer case plugs use copper compression washers - you need two at $1 each.

At 80,000 miles, with the last change at 40,000 miles - the differentials both looked good. The fluid was still quite clear if a bit stinky. The transfer case was just ok - not too much red left, more of a brown color. The transmission fluid also didn't have a lot of blue left in it - I would call it dark gray. Just a very small amount of fine fuzz on the magnets - a lot less than I had at the 40k service, and no metal in the transmission filter.

Other loveliness. I have had the truck in a few times at the dealer in the last year for some major services under warranty - oil cooler seal for the second time, engine mounts, and some other such goodies. In doing the 80,000 miles services on the truck in the last two weeks, I started noticing missing bolts and black zip ties. In about half a dozen places, the mechanics at the dealer either broke or lost special order parts, and instead of fixing them correctly they just zip tied the pieces together or left them missing altogether. Amazing. How do I know they are all special order parts - because I just ordered and replaced them... So much for white-gloved Mercedes technicians...

Oh - I do have Torque pro - and while it does show a value for transmission temperature on the GL, on my truck the indicated temperature was clearly wrong. The pan was cold to the touch and Torque was showing a temp of 110 degrees, after only a minute or so of runtime.

 

 

I use Motul ATF 236.14 oil for the transmission. To my knowledge, the only 100% synthetic ATF oil allowed by MB, besides their own AMG product.

Running better in the cold, and with lower temp, while driving, according to readout from DAS/Xentry.

Be aware that oil's called "Full Synthetic" are NOT 100% synthetic oil's.

 

What transfer pumps are people using?

 

I use a hose and a funnel, instead of a pump. I raise the funnel over the cars roof, and pour in the oil.

Rool down the windows, Attach the funnel to the door frame with a plastic strip, and pour in the oil.

Cheap and works.

 

I use my motive brake bleeder tank.. works great and has an off valve to minimize spillage.

 

every semi- serious home mechanic should have a motive brake bleeder kit with the necessary adapters.

 

If this comment was related to me, yes sure I have that, but I use it for brake fluid, not ATF oil.

The risk of con terminating the brake fluid with ATF oil is there, and since DOT4 fluid is based on Glykol and not mineral oil, ATF and brake fluid don't go well together on our cars.

 

oh, i wasnt picking a fight. i wasnt even thinking about you when i posted my previous post.

 

I use Idparts.com for purchasing fluids/filters, send them your vin and they’ll set you up w the proper fluid. I’d definitely use das to make sure of proper temp. If you don’t have a das setup, call a reputable Indy, or use dealer. I’ve personally had better experiences w/ a local Indy then our local dealer, but their techs seem to have a pretty high turnover rate for what it’s worth. I’ve only done trans fluid, but have diffs planned soon, I’m at 99k mi now. 2¢ worth whats charged.

 

Today I found another source of mbz 235.7 and 235.74 compliant differential oil for the GL. Red Line 50104 75W85 GL-5 Gear Oil.. they have it at Amazon for $20 per quart... nice to have an alternative to the Mercedes brand liquid gold.

 

Which one do you have? I am thinking of picking one up. I want to take the mess out of this.

Actually thinking of ordering this too to lift it up.
https://www.homedepot.com/p/QuickJac...-309646718-_-N

 

Has aonyone run this fluid?

I am thinking I will drain/fill/filter this fall. I will drain/fill in about a month and then in the spring do the drain/filter/fill before towing season starts back up.