Solved: Will Foxwell NT520 Pro work to monitor transmission fluid temp? (yes)

[haigha]

I'm going to replace the transmission fluid as part of replacing the Transmission Sealing Sleeve.

The procedure says to maintain the fluid at 30 to 35 C when checking the level (N62 ZF):

https://www.zf.com/unitedkingdom/en_...hange_oil.html

Does the Foxwell NT520 Pro monitor the real-time temperature of the transmission fluid?

From what I've read online Torque with a simple OBD II adapter can't see the temperature on E53s.


Thanks!

[andrewwynn]

The normal process is to use an infrared thermometer. I thought I saw temp with the foxwell I'll try to check for you when I hook up the scanner next.


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[haigha]

Originally Posted by andrewwynn

The normal process is to use an infrared thermometer. I thought I saw temp with the foxwell I'll try to check for you when I hook up the scanner next.

Thanks for the advice. Do you just shoot the bottom of the pan with the infrared thermometer?

Please let me know on the Foxwell, if you get a chance. Seems like that would be more accurate.

[andrewwynn]

Yep bottom of the pan will be close enough to keep you in the required range.


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[oldskewel]

Originally Posted by haigha

...The procedure says to maintain the fluid at 30 to 35 C when checking the level (N62 ZF)...

Not sure where you are located, but in many parts of the US right now, daytime high temps are around 30*C. Normal human body temp is 37*C. Those numbers are cold, so to "maintain the fluid" at that temp will require an ice bath or something similar. Really.

If you care about following the procedure (you should), I'd be more concerned with how to measure level while it's at that temperature, rather than what specific instrument you'll use to measure it.

It may be a matter of setting the level ASAFP as things quickly warm up through and past the specified temperature range. No maintaining. It's a transient state.

What I do (I have a different AT on my 3.0i, but similarly low temp spec for setting level, so this issue is the same) is to slightly overfill the day before setting the level. Overfilling can be done by jacking the vehicle asymmetrically to raise the fill port higher than it would be when flat.

Then the following morning, once things have cooled down, I go through the sequence as fast as I can, which hopefully does not exceed the temp range spec, and remove the already loosened fill plug to let fluid drain to the proper level. This way it can all be done very quickly, which I have found is the difficult part about hitting that temp spec.

BTW, I have never heard an explanation for why the temp spec is so low on this procedure. And it's like that for all German cars I know of - Porsche, BMW, Mercedes, at least. Does anyone know why they do it there rather than at a temperature that would actually be stable, such as 85*C? And that's the same issue for ZF, GM, and Aisin transmissions on these cars at least, too. (German, French, and Japanese, respectively). So I bet there's a good reason.

[haigha]

Thanks for the great advice Andrew and OldSkewel!

The asymmetrical jacking and waiting til the next day idea is genius. I think the later ZF 8 speed has a max of 40 C which is a little more reasonable, especially in the summer.

I went ahead and ordered the Foxwell. Seems like it will be useful for other things. I'll try to update this thread when I verify whether it monitors the temperature.

[andrewwynn]

That is a very strange curiousity regarding the cold temp for setting the level.


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[andrewwynn]

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[haigha]

Originally Posted by andrewwynn

<edited out pic of 58 C >

Thanks, Andrew!

Glad to be back in this awesome community.

[wpoll]

It's a bit harder to overfill the trans with the bottom-fill pans.... Asymetrical jacking won't alter the level much as the fill port is on the centerline... You could try it with the front of the car much higher than the rear (assuming the fill port is towards the front of of the pan).

But using the mityvac fluid pump to fill the trans should give you enough time to complete the fill before temps get too high. And remember, you are adding cold fluid which lowers the temp a little as you fill (although you don't add much at this point in the fill process).