changing the transmission fluid

[Armando]

Questions, when changing the transmission fluid should I change the filter as well or just the fluid is sufficient enough. 1985 720 98k miles 

 

thanks 

[Stoffregen Motorsports]

I'm guessing it's an auto trans?

[Bleach]

Changing the fluid itself is more important. If you have more time to invest and you want to be thorough, then of course go ahead and put a new filter in.

 

In my cars with an auto, I just change the fluid more often than is necessary and don't change the filter out.

[datzenmike]

It should be changed every 30,000 miles or if the color changes and more often if you tow with it. My advice is simply never tow. If you must, get an after market, in line transmission oil cooler for additional cooling. Heat destroys the automatic transmission. ATF should be clear and bright ruby red. The 3N71B in the 720 contains 5.5 liters or just short of 6 US quarts. Most shops will recommend a full flush to displace what's in the torque converter but if the fluid is bright red I wouldn't bother. Never never never overfill. If you accidentally do, take one of the cooling lines off the bottom of the radiator and idle the engine to  pump some out. If topping off, add sparingly with the transmission hot, engine idling, till it reads full. 

 

Under 100k is good. Next time do the filter.

 

 

[CharlieWhiskey]

 The filter is made of metal. When changing the filter, the bolts must be torqued down. There is a lot of ATF behind the filter, and if you apply a little air pressure to it, it will come down due to the release of "surface tension." 

[ElliotV]

On 5/6/2024 at 5:34 PM, datzenmike said:

It should be changed every 30,000 miles or if the color changes and more often if you tow with it. My advice is simply never tow. If you must, get an after market, in line transmission oil cooler for additional cooling. Heat destroys the automatic transmission. ATF should be clear and bright ruby red. The 3N71B in the 720 contains 5.5 liters or just short of 6 US quarts. Most shops will recommend a full flush to displace what's in the torque converter but if the fluid is bright red I wouldn't bother. Never never never overfill. If you accidentally do, take one of the cooling lines off the bottom of the radiator and idle the engine to  pump some out. If topping off, add sparingly with the transmission hot, engine idling, till it reads full. 

 

Under 100k is good. Next time do the filter.

 

 

Yeah towing with a automatic is very hard on them my grandfathers f250 is on its 4th trans in 280k and almost due for another even with a aftermarket cooler and keeping out of overdrive which is part of the reason why I like a manual truck since usually all you have to break/burn up is a clutch. If a filter isn't hard to do or cheap it wouldn't be the worst thing in the world to do I am sure those autos aren't very easy to find so some preventative maintenince never hurts..