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Old 07-12-2019, 12:06 PM
oldskewel oldskewel is offline
Join Date: Nov 2014
Location: SF Bay Area
Posts: 881
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Originally Posted by haigha View Post
...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.
2001 X5 3.0i, 190k miles, AT, owned since 2014
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