overdrive question

[MooseXJ]

ok new to auto tranny and would like to know how and why overdrive works, i always figured i needed to be in 4th or the D all the time even on the highway, but starting in 3rd on the highway is better and will kick into overdrive? better on gas also??? around town, yall in 3rd or 4th?
i notice my tranny shifter is different than our zj which has 1,2 and Drive
mine has 1-2, 3 and Drive. just curious, makes me sound stupid, but hey, never had an auto before

 

[langer1]

It's Automatic just leave it in D, the is that exact same thing as 4th.
It will shift into 4th gear (Over drive) when you going fast enough. Third gear is for times like when your pulling something and you don't want to use 4th gear.

 

[Matthew Currie]

By the way, this particular tranny has not only overdrive, but a lockup torque converter. In the "D" position, the torque converter will lock in both third and fourth gears. In the "3" position, I believe it will lock in second and third, but I may be mistaken (not home to look at references). This feature can make it difficult to figure out what gear you're actually in when you look at the tachometer, because it will sometimes seem to shift through five gears, the last being actually the lockup in fourth. If you take a long time to accelerate it can be even more confusing. My 87 would sometimes lock up in third and shift into fourth without unlocking, and sometimes unlock, shift and relock, depending on how hard you were pushing it.

 

[MooseXJ]

It's Automatic just leave it in D, the is that exact same thing as 4th.
It will shift into 4th gear (Over drive) when you going fast enough. Third gear is for times like when your pulling something and you don't want to use 4th gear.

ok so drivning in D is actually 3rd starting off, but when it goes to 4th that is the over drive, and being in 3rd only, it only stay at 3rd, if thats what ur saying, that makes since.

 

[langer1]

ok so drivning in D is actually 3rd starting off, but when it goes to 4th that is the over drive, and being in 3rd only, it only stay at 3rd, if thats what ur saying, that makes since.

No thats not what I'm saying.
If you leave it in D it will start it 1st and shift to 2nd, 3rd, 4th, and lockup.
If yours is starting out in what ever gear you have it in then the TCU is not working.
Look for a blown TRAN fuse.

 

[MooseXJ]

yeah thats how i drive it D all the time, but a guy i wheel with says put it in 3rd and it will shift to overdrive, so that makes since what you say, and is what i always thought, i guess he was mistaken. but he does drive a 5speed so makes since, thanks for clearin it up.