Transmission Fluid Change Question

[iamezrydr]

We are new owners to a 2002 Itasca Suncruiser 32V. We picked it up last year with 35k mileage and have nearly 40k on it now. Being a Licensed A & P Mechanic, I am no stranger to caring for any vehicle I have. I have done just about everything I needed to do on this unit to maintain her road readiness as seen by the nearly trouble free 5k we have put on it in the past year.

Here is my question: Even though there is considerably low mileage, there is nearly 18 years since sold new. So, I have no transmission troubles I just wanna be proactive. I noticed there is a drain plug on the transmission pan, A Mechanics dream ! At any rate I want to take advantage and replace the transmission fluid or as much of it as I can without dropping the pan. I have researched and found out the system holds 17.7 quarts of Dexron Mercon ATF. So, I would like to drain it and then refill it. Taking into account the fact that the torque converter holds fluid, approximately how much? And also taking that into account how much fluid should I consider purchasing for the fluid replacement?
Thank you in advnce for your assistance in answering my question.

[Topsail]

Start off by reading your dipstick. If it's within specs then you could carefully capture and measure what you drain. This will give you the best idea on how much to put back in.

Why are you opposed to pulling the pan and changing both the spin on and internal filters (if it's an Allison?). There are some good video procedures on this. I believe you are at the mileage for a complete change.

Good luck

[Topsail]

By the way, welcome to the forum. I didn't realize this was your first post.

[Goodspike]

Welcome to the forum. It might help to specify the engine and transmission (if possible).

[al1florida]

I have changed the transmission fluid on a 2005 Ford Class C (Van chassis) and a 2006 Ford Class A (Ford F53) and both have taken about 7 quarts of fluid when only the drain plug pulled or the pan was dropped.

Ford calls for a very specific transmission fluid. I had to search for place to get the Mercon fluid. Neither NAPA or O'Riles's carried the Mercon.

Some other fluids say they are OK to use, but I never did want to take the chance.

[mdka99]

If you have a workhorse chassis with the allison 1000 trans you should change the oil to synthetic. Allison Approved TES 295® fluid is recommended. I did mine last year, very easy with the external filter, Allison only recommends changing the internal filter if the trans is removed. Mine dropped oil temp 10 deg.