Thoughts on changing transmission fluid

[Dustin Jackson]

Do it, if it’s gonna die it’s gonna die... new fluid will only help prolong the life...

@CaptainAmerica1 That's exactly how moving parts in a vehicle work, they will fail unless they have good fluid.

 

[tmt502]

So I changed the fluid, filter, and gasket today. Just changed out what was in the pan, I didn’t flush. Will likely change it again in 20k miles just because that’s how I am.

I towed our boat to the lake and back (about 40 miles, lots of hills) on Friday and Saturday (pre fluid change). Watched the trans temp the whole time. Peaked around 208 but mostly ran around 200 while towing. I had it in trailer mode the whole time. It shifted and pulled very well. I was impressed honestly. Was figuring any issues would show themselves then. Other than the temperature, I was happy.

Very interested to see how the temp will do after the fluid change when we go back to the lake next weekend.

I definitely noticed ‘heat soak’ effect in stop and go areas we drive thru on our route. Once we got moving the temp would drop again. On occasion, it would drop down to 197 or so, but that was only during times of constant movement.

So glad I chose this truck as my towing vehicle!

Also, getting the feel for backing and maneuvering a trailer was a little intimidating at first because it’s been so long since I’ve towed anything, but the backup camera helped me more or less get the hang of it again pretty quickly. Still need more practice, but I was pleased that it didn’t feel totally awkward. No better place to learn than at a busy boat ramp!

 

[Meccanoble]

So I changed the fluid, filter, and gasket today. Just changed out what was in the pan, I didn’t flush. Will likely change it again in 20k miles just because that’s how I am.

I towed our boat to the lake and back (about 40 miles, lots of hills) on Friday and Saturday (pre fluid change). Watched the trans temp the whole time. Peaked around 208 but mostly ran around 200 while towing. I had it in trailer mode the whole time. It shifted and pulled very well. I was impressed honestly. Was figuring any issues would show themselves then. Other than the temperature, I was happy.

Very interested to see how the temp will do after the fluid change when we go back to the lake next weekend.

I definitely noticed ‘heat soak’ effect in stop and go areas we drive thru on our route. Once we got moving the temp would drop again. On occasion, it would drop down to 197 or so, but that was only during times of constant movement.

So glad I chose this truck as my towing vehicle!

Also, getting the feel for backing and maneuvering a trailer was a little intimidating at first because it’s been so long since I’ve towed anything, but the backup camera helped me more or less get the hang of it again pretty quickly. Still need more practice, but I was pleased that it didn’t feel totally awkward. No better place to learn than at a busy boat ramp!

I normally change out the pan fluid, let car start and run for a little so things get mixed. Go through all the gears, then change out the fluid again. You will see the fluid may still be a little dark after just changing pan fluid. You can get something that takes the fluid out from the same place you put it in. Harbor freight cheap fluid pump does the job. A little slow but you can easily pump out the fluids in the pan. You did the hardest part which is change the filter and clean the magnet.

 

[tmt502]

Just wanted to post an update from my general driving and towing experience since changing the fluid.

For normal driving, shifts seem smoother. I might be biasing myself to think that, but I honestly believe they feel smoother. Fingers crossed that this continues. I'll likely be draining and replacing again at the end of boat season, just for peace of mind.

I towed the boat on Friday and Saturday (about 40 miles one-way to the lake). Shifted great, pulled strong, no real difference at all. Fluid temps still seem to be running around the same mark though (±200 degrees). Temps drop some on long stretches with no stop-and-go. Temps go up some when I hit areas with traffic lights. Max speed is sometimes around 55, but mostly 45 max (two-lane highway in rural areas). Should I be concerned with the temps? Is a trans cooler necessary?

 

[89Suburban]

I normally change out the pan fluid, let car start and run for a little so things get mixed. Go through all the gears, then change out the fluid again. You will see the fluid may still be a little dark after just changing pan fluid. You can get something that takes the fluid out from the same place you put it in. Harbor freight cheap fluid pump does the job. A little slow but you can easily pump out the fluids in the pan. You did the hardest part which is change the filter and clean the magnet.

What pump do you have? Does it fit down the tube without issues? I am in the market looking for one. I am reading some horror stories in reviews about suction tubes being too big and not rigid enough and getting stuck in the pan/tube, even in crank cases/crank shafts.

 

[gooffeyguy]

What pump do you have? Does it fit down the tube without issues? I am in the market looking for one. I am reading some horror stories in reviews about suction tubes being too big and not rigid enough and getting stuck in the pan/tube, even in crank cases/crank shafts.

I use a MityVac 7201 fluid evacuator and it comes with rigid hose that's about 1/2" diameter then it has a rubber coupler and a smaller 1/4" rigid hose attaches to that and is fed down the dipstick tube.

Mine extracts or pumps fluid, depending on what you have the selector set on.
Harbor freight sells a bit cheaper one that's almost identical, and also one that just extracts.

https://www.harborfreight.com/deluxe-manual-fluid-extractor-and-dispenser-56384.html

https://www.harborfreight.com/23-gallon-manual-fluid-extractor-62643.html

 

[Meccanoble]

What pump do you have? Does it fit down the tube without issues? I am in the market looking for one. I am reading some horror stories in reviews about suction tubes being too big and not rigid enough and getting stuck in the pan/tube, even in crank cases/crank shafts.

I successfully used the orange popular harbor freight pump. It comes with a slim line connector which I connected to a clear tube. I will reiterate that the pump process is SLOW and a bit clumsy. The fluid kind of goes on its own when you get the pump going but super slow. When I pump too fast, I get a lot of air but if I pump slower or give a little time between pumps, you can feel more fluids going.

Why I like this? The pump itself is super cheap unlike the mytec and others (under $15?). Secondly, this is a super clean process. Unlike my first tranny fluid change that was a mess, I dripped nothing this time around. The pump process probably took a good 5-10 minutes and moving the clear line in and out at different times to try to get all angles of the pan and make sure it all came out. For a business, I would recommend something better but for the standard home that has to do this process maybe once every 3-5 years per car, it fits the budget. I used this for power steering fluid as well.

 

[Meccanoble]

https://www.harborfreight.com/multi-use-transfer-pump-63144.html

Super cheap. There are youtube videos showing how to set it up to pump with the smaller hose setup. I have to say again that the pump process is super slow and a little clumsy compared to the more expensive pumps but you cant beat $7 vs over $100.

 

[thompsoj22]

since the filter is changed simply use the flush method with the trans return line, It is to simple not to do it this way and the most effective method of fluid exchange.

 

[Meccanoble]

since the filter is changed simply use the flush method with the trans return line, It is to simple not to do it this way and the most effective method of fluid exchange.

The only reason I dont like this method is:
1) It requires 2 people
2) There is a danger zone where the fluid is almost out and you can over suck the fluid causing possible problems with tranny. People say to stop when you see the bubbles but what if someone goes too far?
3) the clip that holds the line in can get lost and a little hard to remove/reinstall
4) Opinion: Higher risk for damaging tranny since you are removing fluid while transmission is running?

The only benefit of this process is that it is way faster and probably gets out more fluid at a time than the way I suggested. Would this info be accurate?