what signals a need to change ATF?

[Lockasiam]

Fluid changes on A/T with unknown history, when fluid change would be good and when it would be detrimental?

I’ve already done a thread on my specific vehicle and the consensus was that I could probably do a drain and fill for better shifting, longevity, etc etc. More generally, is there a telltale way to know that changing your ATF would reap benefits or if it’ll cause neutral soup? This is without dropping the pan so really only by examining fluid scent/colour on the dipstick. Or maybe an extractor and inspecting fluid in a jar

 

[Patman]

If you don’t know when it was last done then it’s definitely a good idea to do a drain and fill as soon as you can.

I think that if you were to wait for any kind of symptoms to appear (hard shifting, slipping, etc) then the damage is likely already done.

 

[Lockasiam]

With the van it’s not really a hard shift with slamming, it’s more a bump shift and delayed upshifting at WOT, most noticeable going from 2-3 at 70-75mph where it’ll hold 5500rpm for a while unless you let off then go back on the throttle

 

[Cujet]

Fluid changes on A/T with unknown history, when fluid change would be good and when it would be detrimental?

I dispute the idea that changing the fluid is detrimental. Automatic transmissions are mechanical devices. It is either worn out, has failing components or it does not. Fresh fluid is not the proximate cause of failure.

Are there examples where a transmission acted up after a fluid change, yes, of course. Did that transmission have long to live otherwise? Nope. Did they use the proper factory fluid? Probably not.

Change the fluid properly. Use the exact proper fluid. Do not choose a 'universal' fluid and expect good results.

 

[martinq]

Fluid changes are never detrimental except for disposal and fluid costs / logistics.

Old, worn out fluid gets corrosive, loaded with metal and has lost its friction properties. It's basically grinding / polishing compound.

Do yourself a favour and drop the pan to clean it and the magnets, annually, until they stay clean.

 

[Hall]

Fluid changes on A/T with unknown history, when fluid change would be good and when it would be detrimental?

Stop repeating or spreading this old wive's tale

With the van it’s not really a hard shift with slamming, it’s more a bump shift and delayed upshifting at WOT, most noticeable going from 2-3 at 70-75mph where it’ll hold 5500rpm for a while unless you let off then go back on the throttle

Based on that, what's the harm in changing the fluid ?

 

[BHopkins]

The concept of preventative maintenance is to service your vehicle before performance degrades, or fluids start to wear out, or there is any mechanical wear. Why wait until the transmission no longer shifts smooth, or until the transmission is starting to wear excessively.

 

[IndyIan]

Distance and/or time is the easiest way to know when to change the fluid. For the time and cost of getting an analysis, you might as well just change it. Then you know its good now, and you know when to change it next.
Waiting for any kind of mechanical symptom is a very bad idea if you want to keep the car. I would think the gradual change of noise or performance would be hard to notice until real damage is done, then changing the fluid won't help!

 

[crashz]

I feel like oil changes, ATF changes, and cardiac health are very similar. If you are seeing evidence that something needs to be done, its already too late. Other than holding a gear a little long, I don't see any issue. That means its a perfect time to change the ATF.

 

[Glenda W.]

The concept of preventative maintenance is to service your vehicle before performance degrades, or fluids start to wear out, or there is any mechanical wear. Why wait until the transmission no longer shifts smooth, or until the transmission is starting to wear excessively.

100%

 

[We're Metals]

In a world where dealerships make money servicing vehicles, I wonder why manufactures have moved to "Lifetime" oil for automatic transmissions. Especially when some transmission manufactuers (Looking at you ZF) specify 60,000 - 80,000 fluid changes.

That being said, I change mine. If its a pain in the butt, I'll extract through the dipstick tube. No issues yet

 

[Hall]

In a world where dealerships make money servicing vehicles, I wonder why manufactures have moved to "Lifetime" oil

What's the connection ? Dealerships and automakers are two, separate entities. Just look how dealers make up their own 10k mile, 20k mile, 30k mile, and so on "services" and recommend "A/C system cleaning and flushing" or "complete fuel and intake system service". Look for those in any factory service schedule.... you ain't gonna find them.

 

[FTTSHO]

Changing the fluid and filter every 30k miles for any automatic transmission will ensure you get the most life out of it. If you’re towing, check the transmission fluid every 5k miles, and make sure it doesn’t smell funny. If it starts to smell slightly burnt or acidic, just change the fluid, because if it smells funny, it means the fluid is starting to break down from heat, and it can also mean your clutches might be starting to slip slightly. You never want to get to this point and then try to change the fluid, because damage has already been done if fluid smells burnt or acidic.

A/T fluid has to lubricate all the planetary gears, bearings, clutches, it also has to remove heat from internals, and also maintain the proper viscosity to allow proper fluid pressure for gear changes, and has to maintain proper viscosity which allows proper pressure to hold gears.

Just change the fluid every 30k miles. Cheap insurance. No reason to really use any boutique AT fluid. Just change the fluid often enough with any good fluid that meets your transmission’s spec, and you’ll be fine.

I just do not see a reason why we should go 60k miles or even longer when good fluid and filter is very affordable and easy to swap out compared to a transmission rebuild or a replacement. Automatic Transmissions are incredibly complex and intricate, and to get it rebuilt or replaced will cost an arm and a leg. Frequent fluid changes are all we DIY people or just people who care about their vehicles can do to make it last.

 

[SubieRubyRoo]

With the van it’s not really a hard shift with slamming, it’s more a bump shift and delayed upshifting at WOT, most noticeable going from 2-3 at 70-75mph where it’ll hold 5500rpm for a while unless you let off then go back on the throttle

What van? If it’s got one of Ford’s 6F35 or 8F35, it may be that the fuzzy logic needs a recalibration. You can do that with ForScan and a laptop, some aftermarket tuners, or the good ol’ disconnect both battery terminals for a half hour, depending on the year. More info please. But new fluid never hurts, unless it’s the wrong type for the transmission…

 

[Dragfluid]

Fluid changes on A/T with unknown history, when fluid change would be good and when it would be detrimental?

I’ve already done a thread on my specific vehicle and the consensus was that I could probably do a drain and fill for better shifting, longevity, etc etc. More generally, is there a telltale way to know that changing your ATF would reap benefits or if it’ll cause neutral soup? This is without dropping the pan so really only by examining fluid scent/colour on the dipstick. Or maybe an extractor and inspecting fluid in a jar

Is it really that difficult to include the basic info on your specific vehicle in THIS thread? Then you can be helped better.
As far as changing the fluid, if you have one with a bottom pan, please drop the pan and do it that way, and change the filter, also.
And please, please don't add any "snake oil" to the unit. (conditioner)

 

[Kira]

I wonder why manufactures have moved to "Lifetime" oil for automatic transmissions.

Because omitting servicing the transmission lessens projected maintenance costs.
An advertised vehicle will appear cheaper on paper.

 

[Sam_Julier]

Mileage. Every 20k each car gets a cooler line exchange and new filter. 12-15 quarts of new fluid that meets or exceeds the OE spec.

 

[Lockasiam]

Is it really that difficult to include the basic info on your specific vehicle in THIS thread?

This thread is supposed to be more general. On the wives tale side of no fluid changes on a HM transmission, I’m trying to figure out if it holds any weight but everyone is saying here if a change causes problems that the problems were gonna happen anyways

 

[Dragfluid]

This thread is supposed to be more general. On the wives tale side of no fluid changes on a HM transmission, I’m trying to figure out if it holds any weight but everyone is saying here if a change causes problems that the problems were gonna happen anyways

If a transmission has an issue, changing the fluid isn't going to fix anything. Changing the ATF is maintenance. Just like changing the engine oil.
If the rods are knockin' in your engine, new oil isn't going to change that.

There is ONE unit that contradicts what I said above. And that's the Ford 4R70W. When the fluid gets really oxidized, you can get TCC shudder. Changing the fluid will usually fix that issue, as long as it hasn't gone on too long.

 

[clinebarger]

There is ONE unit that contradicts what I said above. And that's the Ford 4R70W. When the fluid gets really oxidized, you can get TCC shudder. Changing the fluid will usually fix that issue, as long as it hasn't gone on too long.

Including the Ford 6R80 & GM 8L90.