transmission filter/flush 2011 gmc 2500hd

[Ray Thomas]

I want to change the fluid, filters and flush the transmission and torque converter on my 2011 gmc 2500hd duramax. I saw a video online that used a Hayden fitting at the trans cooler return line. They put a clear tube from that fitting into a bucket and with the engine running poured fluid into the trans as the old fluid came out of the torque converter. I don’t know if they make a fitting like that for the 2500hd, I think they were working on a 1500. Do you have a better way of flushing the converter or a part number for an adapter?
Thanks, Martin

Topic

[Richard Kirshy]

Mileage???
Has the transmission ever been completely flushed before?
If not may not be the best thing to do.

[Ray Thomas]

The truck has 110,000 miles and the fluid has never be changed or flushed. The spin on filter has been changed twice. Kinda dirty.

[Richard Kirshy]

My suggestion would be:
Get 3 filters, 2 cheaper one and one high grade and transmission fluid
1 Do a spill n fill and install a cheap filter and drive it a week.
2 repeat step 1
3 repeat step 1 but install the high grade filter and call it good.

[Ray Thomas]

Should I replace the spin on filter each time too?

[Richard Kirshy]

Yes

[Ray Thomas]

Okay, thanks I’ll getter done.

[Author]

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