[Gabe_B]

Hello everyone, new member here! Here's what I am dealing with;

2003 non-SC Xterra V6 Engine
Rear-Wheel/4x4
Automatic Transmission
126k miles

Recent maintenance/repairs:

Fuel Pump/Filter replaced
Spark plugs changed
Throttle Position Sensor replaced
Distributor rotor/cap changed
Knock Sensor replaced/relocated
ATF drain and fill
Radiator replaced

I have two main concerns with my Xterra, but I'm just going to point out the most concerning;

After replacing the knock sensor and the throttle position sensor, I decided to check all of the fluids to make sure everything was where it was suppose to. When I went to check the automatic transmission fluid, there was nothing on the dipstick. So without hesitation, I topped it off with about a quart and a half or so. From there on out, it hasn't been that low, and fluid has stayed the same, so I'm not sure where it went before. Now I'm experiencing a couple of issues, which I am afraid might be transmission related, which I don't really need right now....

First, there is a surge that occurs, only when I hit 15 mph, and only when I am going slow. If I push on the gas pedal hard enough, I can bypass that surge completely. The surge makes the RPMs go up anywhere between 2500-3000.

Second, the RPMs are a lot higher than what they were before, specifically around 40 mph and 60+ mph. At 40 mph, the RPMs sit at close to 2000 RPMs, and when I start to approach 60, they're nearly at 3000, and continue after that. I know that this wasn't how it was when I first got the car, so it's really worrying me that it's a transmission issue.

Any thoughts on this?

 

[kms1990]

yeah those rpm figures are high, it should be more like 1500rpm at 40 and 2500ish or so at 60 on the 3.3 n/a engine it seems like its not going into over drive correctly, have you tried disengaging O/d yet and seeing if anything changes? might try hitting taht buttona nd see if the rpms go up further or if they remain close to the same, if close to the same then it would most likely be an o/d issue, could be over full on fluid how did you check it? its supposed to be after engine and tranny are warmed up (10+ minutes of driving) engine running while checking, shift through all the gears on the lever staying in each on for a few seconds stopping in park or neutral, take the dipstick out wipe put back in and pull out to check, if you just did it with the engine off or cool and running or not on a fairly level surface you can get a bad reading, especially when engine is off or everything isnt warmed up this will typically result in a lower reading than what is actually there. try checking again as i mentioned above if still full, but not over full you may want to change the fluid completely and the filter as well as the filter is probably clogged up pretty good it being a 1st gen at 126k miles. when changing the fluid you might want to substitute an even amount of tranny fluid with the lucas tranny stop slip stuff, that stuff is ultra thick and actually does help clean the internals and helps with hard shifts. obviously it wont fix anything that is physically broken but it helps with general wear and tear that eventually causes automatics to shift slower and harder. if you are over full you need to drain it to the proper level then see id the issue is better before doing anything else

 

[Gabe_B]

Hi there. Appreciate the reply. When I hit the overdrive button to disengage, the RPMs do increase further. I was actually planning on dropping the pan today just to see what was going on in there, however there were a couple of hard to reach bolts and didn’t really have the time today.

Also just to note, after my first drain and fill I did, the fluid was as it should be, nice pinkish color to it, although it did smell a little foul, but from my understanding, that’s quite normal I guess...

I also did another drain and fill this morning just to make sure the fluid was staying nice and clean. It might have been a little on the full side before, but it’s now right where it’s suppose to, but didn’t seem to change anything. Should I wait and drive it a little or should it have helped a little by now? Still new with the Xterra so I’m not sure what should be happening. I know before the RPMs were never this high, so it’s kind of worrying me that it’s transmission related.

 

[kms1990]

Hi there. Appreciate the reply. When I hit the overdrive button to disengage, the RPMs do increase further. I was actually planning on dropping the pan today just to see what was going on in there, however there were a couple of hard to reach bolts and didn’t really have the time today.

Also just to note, after my first drain and fill I did, the fluid was as it should be, nice pinkish color to it, although it did smell a little foul, but from my understanding, that’s quite normal I guess...

I also did another drain and fill this morning just to make sure the fluid was staying nice and clean. It might have been a little on the full side before, but it’s now right where it’s suppose to, but didn’t seem to change anything. Should I wait and drive it a little or should it have helped a little by now? Still new with the Xterra so I’m not sure what should be happening. I know before the RPMs were never this high, so it’s kind of worrying me that it’s transmission related.

do you know the service history on the transmission? if not its actually usually better to simply leave the old fluid alone on a vehicle over 100k miles if you have no idea what was done to it prior to you owning it. as you are experiencing what many people do, trying to change the fluid on a worn transmission that has not been properly maintained, i would change the transmission filter if you plan on dropping the pan again that will probably help some if not resolve it as i am betting it has not had regular tranny fluid changes as it was supposed to and the filter is gummed up. as i stated abovbe substitute a bottle of the lucas transmission fix, that may help too as most likely the clutches and friction material in the tranny have worn and this is why changing fluid regularly is a must, and when it isnt done after so long leaving it alone is actually better, as the clutches wear, its a very very very minor amount each gear change) they give off some of their friction material (they kind of resemble a drum brake shoe) this material is what turns the fluid black (unless it overheated) well in a vehicle that hasnt had the fluid changed at the regular intervals it has a build up of this material in the fluid, and very worn clutches, well as you drive that old fluid full of the clutch material reattaches to the clutches and keeps them working correctly, albeit maybe a bit slower and harder shifting than before. well taking this old fluid and draining and putting in fresh fluid does, well take a guess, drains all the clutch material too, so the new fluid doesnt have the same properties as the old worn fluid and with the tranny worn it no longer has the material floating around to force it to work right. this is what starts causing the issues, as the old fluid masked the wear and tear. the lucas stuff attempts to help correct this and in some cases can. im normally not a big miracle in a bottle pusher as most of them are simply smoke and mirrors or give you a placebo effect but lucas transmission fix and seafoam are 2 i have seen and felt work with my 2 hands so i believe in them. this is the lucas product i am referring to: https://shop.advanceautoparts.com/p...TSAdmQCejfn7-KNQcboaAlIpEALw_wcB&gclsrc=aw.ds

 

[Generichandle]

Hi Gabe,

Hope it's going well. Three things I'd add:

I have used the Lucas Oil transmission slip stuff, and it has helped me get my ex's horrible transmission in her Honda Odyssey back working decently. I don't recommend using that stuff yet. If the transmission fluid wasn't burnt (didn't smell like burnt toast), then I don't think that's it. One thing is that there are several inputs the computer reads to shift properly. One place I might suggest is checking the throttle position sensor wiring and connector, since it was messed with recently.

Short story here: A friend just recently complained on Facebook that he couldn't go to work because the transmission went out on his Sentra. I bit and checked it out. I popped the hood and checked the tranny fluid. It was dark but still slick and not burnt. Due for a change, but OK, but I saw the entire throttle body (with TPS) was new, just replaced a few months back by the previous owner. I pulled a code for a throttle position sensor. I was not expecting that (totally brought the wrong set of tools). I started digging around and the cable to the TPS was falling apart. I ran to the junk yard as it was about to close, scrounged the harness for $10 and butt spliced it in (crimped with a pair of needle nosers) and he was back on the road (and I got a nice thank-you dinner for my effort). Told him to swing by my place in a few days and I'd solder it in properly. A couple weeks passed and no problems, no codes or anything. When I redid the job right, I found one of the improvised butt splice connections I did was bad (the white wire, for what it's worth, I never looked up what the wires go to). Note that it was not giving a code. I wrapped it up, and he took it for a test drive and came back to announce, "Well, it's shifting better now. I guess the transmission is fine."

As for those old wives tales about not changing the fluid-- if the transmission is that bad, yes, the junk floating in the ATF can add enough friction to help move the car. And yes, changing the fluid at that point will make the problem immediately and clearly worse. If it drives, I don't think that's it. If the transmission were that bad, just get it fixed. You should still have plenty of life in the car. I don't have enough info to say for sure, so I may be wrong, but I just don't think the transmission is the problem here. If you put new fluid in it already and it's basically working, I don't think the transmission is anywhere near that bad.

One thing I would want to know is if you stuck a finger in the old fluid and checked if it still had lubricity. If it still felt slick and didn't smell like burnt toast, then I'd go back and double check the TPS job. It might be a bad wire or connector issue there.

Good luck,

John

 

[Gabe_B]

Hi John. Appreciate the reply.

I had the wiring to the TPS checked before replacing the unit to make sure it wasn't that, but that was some time ago now. Could it be the TPS I bought specifically? Not sure if one brand is better than another or what not.

And yes, the old fluid looked and felt great to me. It did have kind of a weird smell to it, but I'm told that's normal.

Just a quick update now;

The surge is still occurring at around that 15 MPH mark, however, the RPMs have been a little bit lower now, when the engine is warmed up. 40 MPH sits around 1600 right now.

Another thing I have noticed are the shifting points seem to be quite high as well (1st to 2nd, and then 2nd to 3rd). Does anyone know the appropriate/normal shift points, or does that differ on each vehicle?

 

[kms1990]

Hi Gabe,

Hope it's going well. Three things I'd add:

I have used the Lucas Oil transmission slip stuff, and it has helped me get my ex's horrible transmission in her Honda Odyssey back working decently. I don't recommend using that stuff yet. If the transmission fluid wasn't burnt (didn't smell like burnt toast), then I don't think that's it. One thing is that there are several inputs the computer reads to shift properly. One place I might suggest is checking the throttle position sensor wiring and connector, since it was messed with recently.

Short story here: A friend just recently complained on Facebook that he couldn't go to work because the transmission went out on his Sentra. I bit and checked it out. I popped the hood and checked the tranny fluid. It was dark but still slick and not burnt. Due for a change, but OK, but I saw the entire throttle body (with TPS) was new, just replaced a few months back by the previous owner. I pulled a code for a throttle position sensor. I was not expecting that (totally brought the wrong set of tools). I started digging around and the cable to the TPS was falling apart. I ran to the junk yard as it was about to close, scrounged the harness for $10 and butt spliced it in (crimped with a pair of needle nosers) and he was back on the road (and I got a nice thank-you dinner for my effort). Told him to swing by my place in a few days and I'd solder it in properly. A couple weeks passed and no problems, no codes or anything. When I redid the job right, I found one of the improvised butt splice connections I did was bad (the white wire, for what it's worth, I never looked up what the wires go to). Note that it was not giving a code. I wrapped it up, and he took it for a test drive and came back to announce, "Well, it's shifting better now. I guess the transmission is fine."

As for those old wives tales about not changing the fluid-- if the transmission is that bad, yes, the junk floating in the ATF can add enough friction to help move the car. And yes, changing the fluid at that point will make the problem immediately and clearly worse. If it drives, I don't think that's it. If the transmission were that bad, just get it fixed. You should still have plenty of life in the car. I don't have enough info to say for sure, so I may be wrong, but I just don't think the transmission is the problem here. If you put new fluid in it already and it's basically working, I don't think the transmission is anywhere near that bad.

One thing I would want to know is if you stuck a finger in the old fluid and checked if it still had lubricity. If it still felt slick and didn't smell like burnt toast, then I'd go back and double check the TPS job. It might be a bad wire or connector issue there.

Good luck,

John

reason i added the bit on the fluid was simply for the fact of the age of his xterra, and it was most likely purchased used so he wouldnt know how well the tranny was cared for, i had a mazda that only had 75k miles and i changed the fluid, probably its only fluid change ever and it started shifting like crap and eventually started throwing a/t lights and shifting hard even in manual shift mode, checked the fluid no burn smell no darkness before changing but it did not like the change after so long with the old fluid.

Now to the OP, some of what you described does make sense on a faulty, or broken wiring tps, so as he stated check it and be sure all the wires on the harness are in good shape and arent shorting somewhere. could even be a bad tps especially if its a parts store one, the parts store no name sensors can be pretty cheaply made depending on which ones you get. The lucas has helped my 2011 x as it had started to shif hard but i also did a drain and fill then put it in after when it still was shifting a bit harder than i thought it should, though to some extent thsi is normal on conventional type automatics like ours as they age they tend to lose friction and shift just a bit harder as miles racj up.

 

[Gabe_B]

Okay. Thanks for all of the replies. I do plan on dropping the pan soon here also, and clean that out and change the filter as well. That'll probably be the last thing I do towards the transmission, if nothing changes after that, then i'll have to get use to all of the weird things going on.

 

[Generichandle]

Gabe,

Yeah, I'd check the TPS. First consider if it's the OEM Hitachi part or an off-brand, but I think it's more about whether the computer is getting correct TPS information for shifts. Definitely check the wiring. Do that first before anything. I'd say skip dropping the pan. You are aware that the filter isn't really a filter as much as a tin can with screen wire in it, right? If it's plugged, you'd be having major malfunctions. By all means, if you are curious and want to spend money and time and waste almost nine quarts of ATF, go for it, but don't do it to fix this shift issue.

You did put Dextron III in it, or the Nissan stuff, right?



KMS1990,

It's a Mazda. Crappy transmission. You probably don't want to use that as an example. It doesn't really apply to this vehicle. It'll make people think they need to get transmission work when they don't.

 

[Gabe_B]

Hi John. Thanks. I won’t change the filter then. Some of the bolts underneath looked impossible to get to as well anyways. It was a hitachi before, now it’s a no brand.

 

[kms1990]

Gabe,

Yeah, I'd check the TPS. First consider if it's the OEM Hitachi part or an off-brand, but I think it's more about whether the computer is getting correct TPS information for shifts. Definitely check the wiring. Do that first before anything. I'd say skip dropping the pan. You are aware that the filter isn't really a filter as much as a tin can with screen wire in it, right? If it's plugged, you'd be having major malfunctions. By all means, if you are curious and want to spend money and time and waste almost nine quarts of ATF, go for it, but don't do it to fix this shift issue.

You did put Dextron III in it, or the Nissan stuff, right?



KMS1990,

It's a Mazda. Crappy transmission. You probably don't want to use that as an example. It doesn't really apply to this vehicle. It'll make people think they need to get transmission work when they don't.

well technically it was a ford transmission as mazda now sources them elsewhere and are just fine. prior to 2013 though the auto mazdas where ford trannys so yeah not the best example, hell it even had fomoco stamped on the tranny nice and proud. just about every piece in that car had a nice big fomoco stamp on it, which is why i ridded it from my life the engine was built by mazda and a genuinely good engine but the external stuff was basically all ford.... it had more ford stamped parts on it than the 08 manual mazda 3 i had that was a great car. but granted it was a jatco manual and built in their japanese factory whereas the autos are mostly built in their mexico one that they shared with production of ford stuff like the L series engines in both my mazdas are also in the fusion (some focuses most notably the rs but with a ford top end that likes to blow gaskets) the ranger the mustang with the 2.3L and basically any 2.3L or 2.5L ford from 1997-2011 had a mazda motor in it. the engines are built very well, its when you get to the ford parts that bolt to the engine such as the tranny and motor mounts that you see issues as ford designed them, and we all know how well ford designs things..... and yes as you said dex 3 will work, but its not the best for it, something that actuyally has the nissan matic spec for his tranny is best castrol import multi-vehicle specifies matic-d j and k in their data sheets:https://msdspds.castrol.com/msdspds/msdspds.nsf/CastrolResults?OpenForm&c=USA (US)&l=English (US)&p=Import Multi-Vehicle&n=&b=All&t=PDS&autosearch=No&autoload=No&sitelang=EN&output=Full&spu=Lubricants&unrestrictedmb=No&cols=0 and their multi-vehicle full synthetic fluid specifies for all types on nissan: https://msdspds.castrol.com/bpglis/...CCF193E80257BA5006EB93F/$File/BPXE-99LBRT.pdf though on temperamental or older non serviced trannys its usually better to get the specific one from the dealer http://www.authorizednissanparts.com/Nissan-MATIC-D-Automatic-Transmission-Fluid_p_17.html


and as GenericHandle sated check your TPS before doing anything else, sometimes the generic parts store sensors can simply just be crapola in a box with a warranty to get you to buy them. I used to work for Autozone and can testify most of the in store brand sensors are crap, and all the parts stores (orielly, autozone, advance, napa etc all get their house brand from 1 company and slap their sticker and part number on it) i would return nissan crank sensors left and right and always tell anyone in need of one to please go to the dealer, it will save you time and hassle though it may cost more upfront as the autozone crank sensors 1 out of every 10-15ish would actually correct the issue the rest would end up needing the oe brand one from the dealer thwn they started working again.