Hi! I got a 2005 Xterra with automatic transmission. About two month ago had an issue with the radiator, when coolant got mixed up with transmission fluid. The problem was not noticed until the transmission went into safe mode and a MIL light went on. So how long it was driven with the antifreeze in the tranny I'm not sure. But as soon as it happened transmission got flushed and I did a bypass to prevent it from happening in the future. After that it was shifting smooth and there were no codes. Yesterday, during city driving the transmission suddenly "shut down" even though engine was running good. It just lost power and did not accelerate. I pulled over to the nearest parking lot. At the same time MIL light came on along with 4WD light. After I shut down the engine, the starter wouldn't crank or even click when I turn the key. Code is U1000 which I couldn't clear. I searched for bulletins that would refer to this code and found two. One of them is about a bad ground connections either with ECM or the battery terminals. It suggested checking Freeze Frame info and comparing it to the provided chart. If it didn't match exactly as it was stated in the bulletin it does not apply. It didn't, plus I did clean ground connectors just in case and it didn't help either, so I ruled this one out. Another one was issued for 2004-2005 Armada and Titan. It says: "Engine will not crank, and/or start, and/or transmission improper operation". Since Armada and Titan share the same transmission model I think it might apply to Xterra as well. It suggested checking the F9 connector (A/T assembly harness connector) for water or corrosion, which is located on the passenger side of the transmission. I disconnected it and it looks very clean and there was no corrosion or water inside. Could it be something inside the transmission? Did anyone have anything similar? Any help would be greatly appreciated! Thanks!

once you get antifreeze in your tranny it's only a matter of time before it dies. Compromising the friction modifiers in there is catastrophic to the clutch packs, gears, and TC. Your tranny is in safe mode and is preventing the truck from starting right now. Something is obviously wrong inside it IMHO and you should see a tranny specialist or the stealership (if you are under warranty) ASAP. This is most certainly not good.

thenewx.org is a site with many more active users that know about 2nd gen Xterras specifically. you should post up over there as well and see what kind of input you get. Some of those guys really know their stuff. :)

good luck!

-Rook

x2 the tran is toast.

Hey Garik, I just had the exact same problem on my 2005 Xterra. where you able to fix your problem, and if so how? was it too expensive? If you have an answer I would love to hear it! Thank you!

Hi! Yes I had mine fixed. The problem was in the transmission valve body assembly. It was around $900 for the new valve body and about $200 to have it replaced. I replaced it at local transmission shop, but ordered valve body through nissan. Was your radiator leaking into your transmission? What is your mileage? Nissan issued extended warranty on the radiators as this is a very known issue. I think it is extended to the 80,000 miles and covers repairs to the transmissions as a result of this failure. Unfortunately mine was not covered as I was past 90,000 so I paid it out of pocket. Good luck!

Wow thank you so much for the quick response!. I have not located the source of the problem. I don't think the radiator was leaking into the transmission, however I did stalled replacing the transmission fluid. so maybe that's part of the problem. But it definitely has the exact same symptoms as you described. The 4WD came on, the transmission screens went blank, override button does not work at all. It will not start, I then hooked it up directly from the battery to the starter and it started but it won't let me accelerate over 2000 rmp.

Mine is 92K miles and the problem is that I'm located in Costa Rica, so I don't think I'm covered by the guaranty extension you mentioned. I will take it by the transmission shop and give them your insight! thank you so very much for it.

You're welcome! What kind of fluid did you use when you changed it? When I had mine flushed, they used synthetic Amsoil, which they said was equivalent to the Nissan type S fluid. After about two months valve body failed. I'm not blaming it on the fluid, as I heard that Amsoil makes some good stuff, and probably most damage was done by antifreeze in the transmission. But for those two months it was perfectly fine, so I'm still thinking that maybe wrong type of fluid could actually do some damage as well over that period. I'm still wondering why valve body did not fail with antifreeze in the transmission, but failed two months later with the new fluid. The next time when they filled it up after replacing valve body, I actually bought type S fluid from the Nissan and brought it to them, just to be sure. Now for about 9 months I don't have any problems. It's just a thought. Also keep checking the fluid to be sure that there is no antifreeze in it. If there will be moisture contamination it will turn to dirty pink color and will not be transparent. The best way is to bypass the radiator and use only transmission cooler. It takes only couple minutes to do and gives you a peace of mind. Good luck!

Your feedback has been extremely helpful! Seems like we share the same problems. I changed the transmission fluid in march, and now gives me this problem. However I checked the fluid and does not have the dirty pink color that you described, and it hasn't lost its transparency. Nevertheless, your thoughts on the correct fluid made me wonder as well... as the transmission didn't worked properly after the fluid change. I have an appointment at the local transmission shop for tomorrow. I'm sure they'll find this info more than helpful!

Quick question: how exactly did you do the radiator bypass? in case they don't know how to do it and ask. It will sure give me peace of mind!

Thank you again!

Xterras have transmission fluid running through the radiator and then through the small transmission cooler that is mounted on the passenger side right in front of the radiator. All you have to do is to hook up the hose directly to the small cooler instead of the radiator. I don't remember exactly which hose goes where, but if you'll look at it you'll see. The idea is to eliminate radiator from the flow of transmission fluid and use only small transmission cooler. You don't even have to buy hoses, the lengths of the original ones are good. By doing this you'll have one hose extra. Just connect both ends of it to the radiator where transmission fluid passed through before. It is all explained here with pictures: http://www.thenewx.org/forum/showthread.php?t=18557

Thank you for your great advice! You have no idea how helpful it has been! I spoke to the mechanic and he said he's not going to have a problem to fix it! I'll go ahead with the bypass just to scratch it off the worry list! I'll let you know how it goes! Thanks so much again!

Mine threw a U1000 code a couple times on the trail this weekend. I had done the by-pass over a year ago and just flushed the trany about 6 month ago. the 4x4 light blinked and it would not move when put into gear. I let it set for a few minutes and cleared the codes with my reader and everything seemed fine. The only time it happened was on a hard climb. I'm not sure what to do. I checked my ground wire at the battery and it was a little loss so I tightened it and haven't had the problum return.
I also had the fuel tank sending unit code several time but that's for a diff thread.

The U1000 is the code of death...I've known 3 people that have gotten this code, and Nissan could not figure it out. Their vehicles were in and out of the dealer a bunch of times. Ultimately, they all have different rides now: One has a 1st gen, one has a Pathy, and one has a Tacoma.

@garik, there is no way that the Amsoil killed your tranny. It was the antifreeze mixing with the tranny fluid that killed it. There are plenty of people that are running Amsoil that haven't had any problems. In fact, I have been running it for the last 90K miles without any problems.

The Nissan Matic J (used in the early 2nd gens) was corrosive, and it compromised the radiator. Nissan has switched to the Matic S fluid now, and no longer recommends using Matic J. Amsoil meets Matic S specs, and so do several other aftermarket synthetic tranny fluids.

The code of death...Damn that sucks! I'm hoping something just got wet or my battery cable was loose. It hasn't done it since I tightened the cable about half way through the run so I'm hoping that fixed it. I'm more concerned about the fuel sending unit over voltage code. Everything is working good right now so I got my fingers crossed.

http://engine-codes.com/u1000_nissan.html

CAN network issues. Could be a bad/broken connection or wire, or bad ECU (CAN devices are setup with priority levels so more cortical ones get to talk when they want to reduce collisions)

TSB listing for this code:

http://goo.gl/xX9l5

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