[mheacox]

Hello. I have had my 2002 SE/SC Xterra for a few months now and I've noticed an issue with the overdrive gear for a while and just now decided to post here about it. The problem is that my overdrive does not seem to be working for some reason. When I turn my X on, the OD Off light comes on for a few seconds as it is supposed to do and then turns off, but when I am driving it never seems to shift into an overdrive gear. I've tried pressing the on/off button while I'm driving at highway speeds (70-85 mph) and nothing happens. When I press the button it doesn't shift into another gear and the OD Off light doesn't come on, it just stays off the whole time except for a few seconds when I first start it. Can anyone please help me with this issue or tell me some possibilities as to what could be causing this issue? Thank you very much for anyone who can help me.

 

[Cyclemut]

A couple of things we need for some diagnostics.

So what you're saying is that when you're driving, engine warmed up, and you hit your overdrive button on the shifter, the light does not come on?

When you're driving 75mph, what rpm does your tach show?

What is your foot position on the throttle when you're doing 75mph? Quarter throttle, half throttle?

Can you drive down a long hill at speed, let off the throttle totally, see if the overdrive comes on (and note the rpm @ that coast speed)?

Have you tried shifting into neutral, then back into drive at speed to see if it will shift into overdrive?

What happens if you start out in 1st, take it to 4k rpm, shift into 2nd, take it to 4k rpm again, then shift into Drive?

Have you counted the shift and tach drops while driving to insure that it's not shifting?

At around 60mph or so, you should be around 3k rpm.

How good are you at electrical testing? Confident or not?

And to add, where are from?

Welcome to the club!

 

[mheacox]

First of all, thank you very much for your response.

I'll start by telling you why I finally decided it was time to ask for help just to give you a little background in case that helps. Yesterday, I had to drive a Jeep Grand Cherokee for work and I noticed that it had an overdrive also so I decided to test it out to see how it compared to mine. I was driving on the interstate going about 75 or so with the overdrive on and the RPMs were at about 2400-2600. I pressed the overdrive button to turn it off and I immediately felt it shift and the RPMs jumped up to about 3000. I know this is a completely different vehicle, but I just wanted to test out the overdrive to get a feel for how it worked and what I should be feeling in my X.

Yes, I am saying that when I am driving after the engine has warmed up and I press the button the light does not come on. It doesn't just not come on, nothing at all happens. I don't feel any shifting either into or out of overdrive, it just seems like the button is not even attached to anything almost.

I drove on the interstate again today in my X, and as far as I can remember, I was at around 2900-3000 RPM at 75 mph. I've never paid attention to my foot position on the throttle before, but I played around with it a little today trying different positions but nothing seemed to make the overdrive work. I would say I'm probably somewhere between a quarter throttle and a half throttle generally. Probably closer to half usually though.

I don't know of any long hills around where I am but I tried letting off of the throttle on a smaller hill at highway speeds and the overdrive still did not come on. It seemed like the RPMs just dropped around 2000, but it was too busy for it to be safe to slow down too much so I had to speed back up. I can try this again when it's less busy if you think it would be worth it.

I have not tried shifting into neutral and then back into drive yet, but I will when I get a chance and I'll let you know. I also have not tried starting in first and then going to second and then drive but I will try that soon as well.

I did try to count the shifts today while I was driving, but I'm not positive how accurate what I counted was. I believe that I only noticed three shifts, which would put me in fourth gear. It shifted into 2nd at about 20 mph, 3rd at about 35 mph, and 4th at around 60 mph I believe. I continued to speed up to around 80 mph but nothing else happened.

I believe that at around 60 mph, I was at approximately 2600 RPM. I haven't tested this out very much so it might not be completely accurate but i think it's pretty close. Is there any reason why this could be so much lower than the 3000 RPM you said it should be? And what issues could this cause?

I am decent at electrical testing and fairly confident, but I do know people who could help me with anything I can't handle on my own. I am pretty confident that I could test something if I knew what it was though. What are you thinking about electrical problems causing this issue?

And finally, I am from Upstate South Carolina, but I am currently working near Lexington NC. I am 19 and am an engineering major at Clemson. Thank you very much for your time and your willingness to help.

 

[Gustling]

I have the same issue with my '02. OD worked for about a month after I bought it, then worked intermittently, then not at all. About a month ago, I took off the bezel that goes over the gearshift for another project, and I removed my gearshift handle. When I pulled it off the stick, there were 2 white wires that weren't attached to anything at all. A buddy of mine said that's the OD- just have to find where it connects underneath there.


Sent from The Dark Side

 

[mheacox]

That's strange. Did you do anything with the wires to get them hooked back up? If so, did that accomplish anything?

 

[Gustling]

No I didn't. I'm not mechanically inclined, and it was getting dark when I saw those wires. I had to have the X to get to work in the morning, so I was sweating bullets, scared I had rendered it useless, so I put it back together (with the 2 loose wires), and everything was as it had been- still no OD. I'll check it out one weekend when I have some time and someone who halfway knows what we're doing...


Sent from The Dark Side

 

[mheacox]

Oh, alright. Well can you let me know if you figure anything else out on it or get it fixed? I'll do the same for you in I figure mine out.

 

[Gustling]

Sounds like a plan. Not sure when I can get to it to- kids coming in this weekend, going out of town next weekend, but I'm curious to see if I can fix it.


Sent from The Dark Side

 

[Cyclemut]

To start, I was wrong about the rpm for overdrive at 60-ish mph. You're on the money at 2600rpm, you're in overdrive.

You counted 3 shifts. Starting in 1st gear (no shift, when starting you're automatically in 1st), it takes 1 shift to get into 2nd. From 2nd, another shift into 3rd (that's 2 shifts) and one more shift gets you into 4th (overdrive) making it 3 shifts.

Here's what you've got going on though. Your overdrive button is broken. Either the wires are broken off, the button isn't working right or something isn't connected, but the problem is in your button, not your transmission.

Here's what you should do to confirm that you are indeed in overdrive.

At 70mph, go to full throttle. Bury your foot in it and see what happens. If you downshift, the tach jumps up, then you're in 3rd (passing gear) and you just shifted out of overdrive. Take it up to 75mph and let off the throttle. You should feel it shift, watch the tach go back down to normal. If everything just happened like that, then overdrive is working correctly.

At that point, you'll need to get the button diagnosed.

 

[mheacox]

I tried what you said about making it downshift into third gear to test the overdrive. It seemed to work so I guess the overdrive actually is working. Thank you very much for your help. Do you have any ideas on what could be wrong with the button or how to fix it?

 

[Cyclemut]

Typically, the wires break off of the shifter at the base. If you pull your black cover off of the shifter (the one that goes around the shifter, also goes around the t-case lever) you should see the wires that come off the handle. See if they're connected to anything.

Heck, someone could have fixed something in there before you bought it and forgot to connect the connector back in place.

 

[mheacox]

Alright, I'll look in to that next time I get a chance. Once again, thank you very much for your help with this.

 

[2003scx]

When I purchased my 03 with 27k on it I had the same issue. The overdrive was not working and on the highway it never shifted into overdrive- RPMs stayed way to high and as a result the gas mileage was terrible. I asked dealer to check it out since it was still under warranty- they said it was fine. Warranty ran out after few months- so didnt really follow up. For some reason it eventually started working right- I had the tranny serviced a few times- maybe a loose wire somewhere was fixed -not sure. There should be a big difference when you turn OD off- the RPMs should jump. Mine used to rev to about 4k when i was at highway speeds(60+), after it started working the rpms dropped to less than 3k at same speed.

 

[Shannon mac]

To start, I was wrong about the rpm for overdrive at 60-ish mph. You're on the money at 2600rpm, you're in overdrive.

You counted 3 shifts. Starting in 1st gear (no shift, when starting you're automatically in 1st), it takes 1 shift to get into 2nd. From 2nd, another shift into 3rd (that's 2 shifts) and one more shift gets you into 4th (overdrive) making it 3 shifts.

Here's what you've got going on though. Your overdrive button is broken. Either the wires are broken off, the button isn't working right or something isn't connected, but the problem is in your button, not your transmission.

Here's what you should do to confirm that you are indeed in overdrive.

At 70mph, go to full throttle. Bury your foot in it and see what happens. If you downshift, the tach jumps up, then you're in 3rd (passing gear) and you just shifted out of overdrive. Take it up to 75mph and let off the throttle. You should feel it shift, watch the tach go back down to normal. If everything just happened like that, then overdrive is working correctly.

At that point, you'll need to get the button diagnosed.

Mine works when I reset the computer for a day or two then stops. When cruising at 55 when it's working it drops from 3000 rpm's to 2000. When it doesn't shift into overdrive i don't go past 3000 rpm's in fear of doing transmission damage?

 

[MeToo]

The transmission can take any engine speed that you can toss at it without grenading your engine.

If it isn't shifting into OD, going 4000 RPM is not gonna hurt the transmission. It'll eat more gas, but the trans will be fine, so long as it isn't suffering from some issues already.