Coasting: in gear vs. neutral

[Baltothewolf]

Wait guys, can't coasting in neutral at high speeds with an automatic fry the transmission?

[PaleMelanesian]

In most cases it's fine. I can personally vouch that it's fine in a Honda. If the engine is running, there's a pump that's lubricating the transmission.

Some automatics don't tolerate engine-off coasting. Hyundai is one. Some are ok with it. Some have "limits' like Honda: up to 35 mph for up to 50 miles. Since I never coast for 50 miles at a time, I feel it's ok to push the mph limit a bit. Then again, the gains from EOC at highway speed are much smaller than in the city, so it's less relevant there.

[mikeyjd]

Originally Posted by Baltothewolf

Wait guys, can't coasting in neutral at high speeds with an automatic fry the transmission?

I believe that only applies to engine off neutral coasting.

[cRiPpLe_rOoStEr]

Originally Posted by Baltothewolf

Wait guys, can't coasting in neutral at high speeds with an automatic fry the transmission?

It was actually a factory feature in the automatic versions of the Opel Astra, which had been briefly offered in the U.S. and Canada as Saturn Astra. AFAIK this very same transmission was used in nearly every late-90s compact sedan such as your Corolla

[user removed]

I've coasted in neutral (only engine running) in autos for probably a decade, several different cars, regular autos, CVTs, and 23+k in the fiesta powershift.

Engine off coasting in neutral?

You will never see me do that in any auto transmission. In almost ever auto tranny made there are two flanges on the back of the torque converter that engage the primary pump of the transmission. When you turn the engine off, the torque converter stops rotating, since it is bolted to the crankshaft, so you have no primary pump and no pressure for gear actuation or lubrication, and neutral needs activation to unclamp all of the bands that engage the planetary gearsets.

Would you run your engine without oil pressure intentionally?

You will never see me coasting in neutral, with the engine off, in any auto transmission, until the manufacturer guarantees me that they will replace the transmission if it fails.

They won't.

Engine on only in autos. Engine off is risking a several thousand dollar repair, in many cases more than the car is worth.

Manuals are fine with engine off coasting.

regards
Mech

[Baltothewolf]

Originally Posted by Old Mechanic

I've coasted in neutral (only engine running) in autos for probably a decade, several different cars, regular autos, CVTs, and 23+k in the fiesta powershift.

Engine off coasting in neutral?

You will never see me do that in any auto transmission. In almost ever auto tranny made there are two flanges on the back of the torque converter that engage the primary pump of the transmission. When you turn the engine off, the torque converter stops rotating, since it is bolted to the crankshaft, so you have no primary pump and no pressure for gear actuation or lubrication, and neutral needs activation to unclamp all of the bands that engage the planetary gearsets.

Would you run your engine without oil pressure intentionally?

You will never see me coasting in neutral, with the engine off, in any auto transmission, until the manufacturer guarantees me that they will replace the transmission if it fails.

They won't.

Engine on only in autos. Engine off is risking a several thousand dollar repair, in many cases more than the car is worth.

Manuals are fine with engine off coasting.

regards
Mech

Thanks Mech, this is the answer I was looking for. I never engine-off coasted in my Camry, and I'm glad now I didn't ;D

[nemo]

Originally Posted by Old Mechanic

I've coasted in neutral (only engine running) in autos for probably a decade, several different cars, regular autos, CVTs, and 23+k in the fiesta powershift.

Engine off coasting in neutral?

You will never see me do that in any auto transmission. In almost ever auto tranny made there are two flanges on the back of the torque converter that engage the primary pump of the transmission. When you turn the engine off, the torque converter stops rotating, since it is bolted to the crankshaft, so you have no primary pump and no pressure for gear actuation or lubrication, and neutral needs activation to unclamp all of the bands that engage the planetary gearsets.

Would you run your engine without oil pressure intentionally?

You will never see me coasting in neutral, with the engine off, in any auto transmission, until the manufacturer guarantees me that they will replace the transmission if it fails.

They won't.

Engine on only in autos. Engine off is risking a several thousand dollar repair, in many cases more than the car is worth.

Manuals are fine with engine off coasting.

regards
Mech

Have to agree. Was in the towing business back in antiquity. Lots of rules about about which automatics could be towed drive wheels on the ground. Some X number of mile at <Y speed others not at all. These assumed the transmission was in good condition. Best bet was flatbed, drop the drive shaft or dolly.

[cRiPpLe_rOoStEr]

Originally Posted by nemo

Have to agree. Was in the towing business back in antiquity. Lots of rules about about which automatics could be towed drive wheels on the ground. Some X number of mile at <Y speed others not at all. These assumed the transmission was in good condition. Best bet was flatbed, drop the drive shaft or dolly.

I wouldn't do so, but an uncle of mine once towed a Pontiac Trans Sport with the drive wheeld on the floor, using a towbar.

I'd rather use something like this if I couldn't get a dolly

[mikeyjd]

Originally Posted by cRiPpLe_rOoStEr

I wouldn't do so, but an uncle of mine once towed a Pontiac Trans Sport with the drive wheeld on the floor, using a towbar.

I'd rather use something like this if I couldn't get a dolly

[oldtamiyaphile]

Originally Posted by cRiPpLe_rOoStEr

Is it just me or are space saver spare tyres getting smaller and smaller?