Transmission (6HP28) drain and fill

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Joe77

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I would like to do a simple drain and fill and for the life of me I cannot find a thread I read a while back on this (next time I will watch the thread, I'm new here!) Couple quick questions...

I seem to remember that the transmission should be within a certain temperature range when filling. Can someone tell me that range? I have the service manual but it does not say. Maybe it doesn't matter?

Second question, can I re-use the drain plug? This is the original pan. At some point I will do the pan swap but for now I would like to get some fresh fluid in there.

I have the GAP tool and I'll be using Mercon SP.

Any help appreciated.
 
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Joe77

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Interesting... This is from the service manual. I thought it was a drain plug. 10mm hex
 

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Shoshone

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Plastic pan should have a plug. Search a bit for proper procedures for fluid fill. The required temp is not very hot. Only open fill plug with engine running!
 

ktm525

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Yeah sorry got my 3 and 4 mixed up. Forget the temp thing. If you are doing a simple drain/refill then just measure accurately what you drained and put that in. That will at least give you a starting point. If you want to use the temperature method then either a IID tool or use a surface temp measure tool. I think it is something like 50C but it should be in the service manual.

update. The level ckeck procedure is just before the drain/fill section in the manual. 30-50C
 

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Stuart Barnes

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Top tip.

Put the new fluid near the radiator or in the sun for a while to warm it up prior to filling. It speeds things up a little while you're waiting for the transmission temperature to get up to specification after the initial fill.
 

Keanan

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"The gearbox fluid level must only be checked when the temperature of the fluid is between 30
degrees and 50 degrees. The fluid level obtained will be incorrect if the reading is outside this temperature
range."

With the GAP tool you can easily read the fluid temp. For those without a GAP tool, if possible, don't do it in an extremely hot or cold environment. Let the engine run for 20-25 minutes so everything is at normal operating temperatures before doing the final top off and putting the fill plug back in.
 

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