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Dropping a automatic transmission from drive to 2nd or low gear in that order to help slow you down if your brakes are failing for example I had my brake booster fail while driving and none of my brakes would work so could you cause damage to automatic transmission if you drop it from drive to 2nd gear then second to low to slow you down mind it I was 80 miles from home it was only way to get home without a tow bill did it on a 2000 4runner 4×4
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Jeez, I hope compression braking doesn’t cause damage. If it did, I doubt it would be a standard feature of every automatic transmission I’ve ever seen. I use it every single day on the hill down to my house. That said, dropping into 2nd from 80 MPH would indeed be bad for the tranny. Also, once I compression braked all the way down Pikes Peak, mostly in 1st, and near the bottom my tranny fluid overheated and the car disabled the feature. So. Common sense.
The way the transmission on this truck is 8f goi drop it down to second the gear won’t engage until you slow down to 55 and low gear won’t engage until the motor is doing 35 so my question could it hurt the automatic transmission it drives fine in drive after the failed brake incident only did it that one day and were I live there isnt any highways it was all city driving at 55 miles an hour
Never had a problem with the tyranny only did it that one time about 2 years ago and lower gears won’t engage at all unless motor is at a serine rpm and speed so 2nd gear won’t engage unless it’s doing 55 mph or slower and low gear won’t bite and engage unless doing ng 35 or slower it shifts fine in drive from 1st gear all the way to 6th gear no problems but the truck does have an added transmission cooler with a larger tranny pan deep dish pan with more trans fluid not seeing any problems just wondering if the myth is true or false or somewhat true
short term use it’s not really an issue.
The problem is with frequent high-rpm (higher than the trans normally downshifts at) downshifting can cause accelerated wear. It’s not a major thing but the sudden pressure spikes can prematurely blow seals and o-rings.
Greatly appreciate the technical aspect of the problem informations is much appreciated love learning new information on stuff like this thank you for the technical side of the situation
If manual shifting an automatic was dangerous, we wouldn’t have “manumatic” automatic transmissions that allow the driver to run the gears manually.
First off evil that doesn’t apply to me I’m talking about a 2000 4runner manumatic automatics didn’t exist till late 2015s so your comment doesn’t apply to my vehicle because it’s to old to be apart of that manumatic didn’t exist at the time my 4runner was made which means it could have been dangerous to shift my automatic because it wasn’t a manumatic
I know your vehicle isn’t a manumatic.
What I mean is, if manual shifting of an automatic transmission is dangerous, we wouldn’t have manumatics to begin with. You were manually shifting your automatic like a manumatic, and you said your transmission matches the selected downshift to a particular engine RPM.
So, in my opinion, you aren’t doing any harm to your transmission. I’d be willing to bet that manual upshifting or downshifting isn’t discouraged in your owner’s manual.
But manumatics automatic transmissions were built specifically to be able to manual shift mine wasn’t built that way
Since your vehicle matches the manually-selected upshifts/downshifts to specific engine speeds, you aren’t doing any harm to your transmission. In reality, you are simply pre-selecting the desired gear, and the transmission performs the shift when safe parameters are met. If you check, it’s recommended to manually shift automatics under certain conditions, such as when descending long inclines to prevent riding the brakes, (just as you did), or downshifting out of OD when towing heavy loads or climbing steep hills.
Having said that, back in the day, you had to be careful with the old school automatics that didn’t have computer input/controls. Those would happily downshift instantly into any gear you manually selected, and could cause engines to rev beyond red line if done foolishly. But, when done properly, say, to meet the driving conditions mentioned above, no harm was done.
There are reasons why automatic transmissions allow you to shift manually. You haven’t harmed your transmission.
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