I've been driving my '99 f150 4x4 around town with overdrive on these entire 2 1/2 yrs. Have I been a stupid all this time? I'm now driving it in off since I've added a set of goodyear ATS 285's. Have I put any strain on the torque converter or tranny all this time? Thanks.

 

You dont want to hear this---YES...the trans has a certain amount of shifts to it in its lifetime...limiting these or extending these will let your vehicle last longer!!!!

besides this you are in the right gear at the right time to get after it if needed...instead of down shifting...

 

My engine has only a finite number of revolutions that it can do through before failure too. Does this mean I shouldn't run my engine either?

 

(Laughing my a$$ off) I have to agree... We should all keep them locked up in the garage all day...

 

Hi Bdog

Leave in/out od. around town...some do/some dont.

I leave in od around town most of the time. Its fairly flat here, so a.t. dosent down shift alot. If a.t. is shifting alot..back and forth between gears..manual shift-to 3rd

Also the tq is working...it unlocks/locks between gears. Took me awhile to get used to this a.t. (last ride 5sp) Sometimes i thought i was in 3rd gear...when actually it was the tq unlocking.
(kinda like a gear between 3rd & OD..but not really)

Of course leaving in 3rd...makes for faster dead stop get aways.

I do agree shifting does wear out anything given enough time.
Seems big tires might cause extra stress/strain..how much, i dont know. Even the motor will wear out from all the rpms.

Good luck...OT

 

Why? With the OD on or off, first gear ratio is EXACTLY the same. There is no difference in launch with the overdrive enabled or disabled.

Mark

 

Hi Mark

Oophs! Your right.

I realized i didnt word that right. Dead stop get aways in 3rd.

Maybe you could help out here....

Locked in 3rd...dead stop...VS...Locked in OD...dead stop.

I understand...stopped...a.t. in 1st gear. OK...

How would one describe the differences?

What would be the difference after launch. locked in 3rd...VS... a.t.(od on) shifting from 3rd to OD?

Does that make sense?

Thanks....OT

 

The only difference with the OD on and the od off is that the transmission won't shift into fourth gear (overdrive) with the overdrive off.

Mark

 

I just leave mine on. When I obay the limit it nevers gets into OD but when I get on it will get into OD it all depends on cops traffic and how I am feeling if I will get on it or not.

 

EXPY, STX---yes guys, the more you run your vehicles, the less time left on them...goes for the trans the engine, etc...anything mechanical is rated to perform its function for a certain amount of cycles...The factory does tests on things like the doors to determine cycle ratings for 100000 opening and closing...this is referred to mean time between failures...

The engines are designed to run reliably for 200000 miles

Since you two made it obvious that you did not know...

Espically the transmission(which is the weak point of the f150 driveline...

I could see that you guys are not up on your statisical process control(SPC)....

Maybe before laughing, you guys check out the facts first---instead of showing your lack of knowledge...

 

In general, if the in town speeds are below 40, it won't make any difference wheter the OD is turned on or off since it won't even shift into OD.

The only advice I'd offer is that if you feel the tranny hunt in and out of OD, then lock od out. Otherwise the tranny is running just fine and there should be no abnormal wear.

Look at it this way - I could drive around in 2nd all the time around the city to prtect my tranny since it would never shift! Unfortunately I've run my engine under a higher RPM for longer causing more engine wear. There are tradeoffs everywhere!

 

There is more then one input to the ECM to control trans shift and T/C lock up points...Some are but not limited to...Throttle position, Ambient temperature, trans fliud temperature, Vehicle speed, Engine speed, etc...

At light throttle mine will shift at ~38mph...

So going down an urban street, you could find yourself in 4th gear...

When you use the OD off button, it just prevents the Transmission from entering OD gear.

Since this website takes the word of the owners manual as gospel, and the bible...It states in there when below 45mph keep the OD off button activated....

Now for the facts---aside fron abusing the transmission by not changing oil regularly, what is the most common failure to the OD transmissions???

Since most of you are not familiar with failure analysis...I will tell you that OD failure is the most common failure...Could this be related to not using the transmission the way that Ford had intended????Could it be that if most people used the OD off button we would see a reduced failure rate of the OD gear???

First two questions I ask someone if they have trans problems would be--Do you change oil regularly??Do you use the OD off button???

I live in the Hill country in Texas and have to use the OD off button.. To this date I have not bought any transmissions for my 4-f150's and 1 f250 psd...I know this one and will continue to use my OD off button....Even the wife uses it....

 

MACH1. Chill, no offense intended. I just think it's ludicrous to disable a useful feature of the vehicle in the name of "preservation." I disengage the OD only when descending steep grades to "preserve" my rotors/linings, a common occurence in PA. I may not be a "five sigma" or whatever failure expert such as you claim to be, but my own personal failure analysis based on 78,459 miles of travel with the OD button hardly used is . . . zero defects, complete reliability. I'd rather preserve the life expectancy of my engine by minimizing rpms through OD use. It's all about choices my friend. Maybe you could report back on the cost/benefit of the OD use issue as it relates to engine life.

 

If you'd like to go the owners manual route, a check of my owners manual does not state to disengage the OD at speeds below 45. My owners manual states that OD should be disengaged under certain driving conditions which may include city drivng if the transmission is shifting Excessively (my emphasis added) in and out of OD. Other reasons listed included for trailer towing and engine braking on long grades. I've only used the OD lockout for the latter two reasons. City driving generally isn't an issue.

There isn't a law written in stone here. Just use your best judgement as to what 'excessive' shifting is!

 

I have noticed that when traveling at very light throttle on even ground that my 4R70W will shift in to OD and the RPM's drop to around 1100 and speedo sits around 38-45 MPH. If I try to accelerate a slight amount (say to go 5 mph faster) the truck will buck or some might call it a lunge. I just know something is not right, but can't pinpoint what it might be. It might be that it is normal and the TC just doesn't know how to act in this exact range or it might just be going shot. I have also thought it might be a bad plug (wires and coils are new) or a problem in the fuel delivery system.

I see no problems in turning OD off in certain areas. I run with mine off all the time, if not because of the hills here in KY the truck would be shifting all the time. It keeps the truck at a constant gear and RPM's are always below 2500 so it's not over working the engine. I have neglected " abused" the tranny in the fact I have not regularly changed the tranny fluid and I might be paying for it now if it is the tranny. A proper tranny fluid change will be done very soon and you can be sure that it will get changed much more often in the future. To me it's a matter of opinion on to use OD or not.