AT w/OD off...heats up gears faster...? (please tell me this is wrong)

[chris kelvin]

I seriously hope i'm right on this, cause if not...i looked like a tool in front of about 5 guys in pep boys...lol.

Ok, i go out to kill some time (cpu is being slaughtered by the spyware removal tools i downloaded) and go to pep boys, mainly to buy a cheap azz flash light....and low rider magazine... I go to the section where they have tires, and like all the 'specials'..like trans flush/oil change etc....just to see what kind of cheap rear winter tires they got.

Now...here's the suspicious part. I overhear the tech/mechanic telling a guy he needs a tranny flush....and the 'customer' was saying how his O/D light is flashing. The mechanic was saying he'd have to get a code read on it and make sure his O/D is working, or else it wont be in O/D and the gears will "cook" as he told the customer. Ok, time for my azz to shine in... I told the mechanic and customer that you can leave the tranny with O/D off, and in fact it is better for the tranny cause it wont be shifting into another gear/band all the time..it will remain in the gear just before...whether it's 4th or 3rd.

Right away the mechanic is like "bro i don't know where you heard that from, if you leave o/d off the tranny heats up cause it's staying in gear, rather then switching to the o/d band".......at this point i'm like, Ummm...Nooo....Ok Scott..lol. I then went on explaining on how o/d is just a gear saving device/method of keeping the RPM's down..... The mechanic said "o/d is made to get the tranny out of a gear, cause it's not good for the car to stay in gear for too long, cause it will heat up the gear and burn it out"....lol.

Um....am i right here...i honestly almost broke out laughing when i heard this guy speak..the customer was like WTF...? So i left and got my magazine and mag lite... BTW i make it a habit to keep my car (a/t 95 4.6 tbird) out of o/d under 45mph...cause if i don't, the tranny wants to keep on shifting up and down between 3rd, and overdrive. Once i get on the highway, o/d goes on...although sometimes i leave it off at like 60mph just for fact that my rpm needle is right in my powerband for passing power.

 

[chris kelvin]

btw i did mention that when o/d is on the tranny is working harder..and the engine is not....take it off, and the engine is working harder, and the tranny is working less.

He wanted to hear none of that.

 

[Gearbanger 101]

Overdrive it for fuel savings, nothing more. It's actually preferred to drive around under load or when towing with the Overdrive "OFF", because doing so can cause it to shift in and out of O/D which is what actually heats things up and causes the O/D band to slip, since it's not a true forward gear. The O/D band/drum doesn't have the holding strength or capacity that the other forward clutches do and abusing it like that will shorten it’s lifespan. Telling the customer that it's going to "heat up" the transmission to the point of failure driving it around with the O/D off is just a dim witted Service Advisors jargon for "we're trying to make more money out of you".

 

[chris kelvin]

Thank you. Yeah if anything OD would actually make the tranny heat up more, especially stop and go 0-35mph traffic.

 

[Gearbanger 101]

Thank you. Yeah if anything OD would actually make the tranny heat up more, especially stop and go 0-35mph traffic.

Well, it shouldn't be shifting into O/D during your average light to light drive at that speed, but driving around under load (towing, steep hills) or shifting in and out of O/D during low speed traffic is what kills it. What speed it shifts into overdrive would depend on the gear ratio of the vehicle it was in and how the transmission is set up.

This is probably a good time for me to promote the use of an external transmission cooler

 

[timeless2]

This is probably a good time for me to promote the use of an external transmission cooler

An enhancement any auto tranny owner should have if they care about the life and durability of their vehicle, IMO.

 

[sgarlic]

Couldn't phrase it better than that, Tim.

 

[Tommy 00GT]

Almost 90,000 miles here and I always drive with O/D off in the city, under 50 mph and when speeds are not constant because traffic. So I would say I drive in O/D off for 50% of the time. My transmission still shifts like when the car was new. I have no transmission cooler and just give it fluid changes every 30,000 miles.

 

[sgarlic]

Yup.. and a tranny cooler will extend the life of your transmission.