Bought a new 01 Qx4, does it need a new trans?

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CanuckQx4
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hey guys, old guy here back from a little hiatus. :inoutgay:

I ended up picking up an 2001.5 Qx4 from a friend of a friend, hes had it off the road for a while now, as he just bought another car when the Qx4 started having problems. Im trying to do some preliminary diagnosis to as what I will have to replace to get the car road worthy.

He said it was having start-up issues ( sometime turn the key to start the car and nothing happens, starter doesnt attempt to crank or nothing, but try 2 minutes later and itll start like a dream, sometimes would take 15 minutes, sometimes wouldnt happen for a week ) Would a new starter solenoid be to blame?

The biggest issue is an aparent shifting issue, he showed me that the transmission had been completely rebuilt only 3 years ago, but was already acting up again,he said sometimes it seems to rev higher like the transmission is slipping, and since I had the car towed to my house, and dont have insurance or plates on it yet, Ive only driven it around the block, but it does seem slow to shift into second or third, but Ive barely pressed the pedal to make it aggressively shift.

If it was slipping. How hard would a transmission swap be? I seen a ton on ebay for $350-500 and that sure beats the rebuild quote of $2500 I got.

Has anyone ever swapped trannies on these 3.5L? This truck is even 2wd so that would help make the process easier Im sure. Could it be done over a week with a knowledgeable buddy or are there specialty tools necessary?

Thanks guys!!


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patqx4
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I wondered where you disappeared to. OT but what happened to your old Q?

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Towncivilian
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Welcome back!

Have you checked the transmission fluid and level? Has the fluid been changed since the rebuild? If not, do a cooler line fluid exchange to get all of the old contaminated fluid out. There is break-in wear from new components and crud from the rebuild process floating in your fluid. The shop may have also used a poor fluid.

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CanuckQx4
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The fluid smells and looks good, hard to get a good gauge level on it. He put some transmission additive in it that even myself Ive read works, but I forget the name, RedLine or something. I dont think its the fluid. I think it may have been a poor rebuild.

Im debating picking up a used transmission, sight unseen mind you off of ebay, but with a warranty. And possibly trying to do this myself over a week or two.

Would it be impossible to do this myself?

Like I said Im not driving the car at the moment but would like to come end of october, so Im just hoping to get it ready, kind of need to drive it around to really find out whats wrong with it though eh? :squint:

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Towncivilian
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Lubegard Red, perhaps?

I'm not sure how difficult it would be to remove and replace a transmission. I can't imagine you'd need too many special tools, but you'll definitely need a transmission jack. The FSM (page AT-278) makes it sound easy with its 16 steps.

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CanuckQx4
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Yes thats the additive that is in it. Still doesnt shift right, Im going to clean the MAF sensor, and just drive the car and see how it performs. Im alost certain I will end up having to swap the transmission.

Even though this one was rebuilt less than 30k ago, its still most likely going to be cheaper if this one is wrecked again to just buy a used one off ebay? I definetely cant handle a transmission rebuild. Just pulling and reinstalling has me scared enough

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Towncivilian
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The problem with buying a used or junkyard trans is that you don't know if it'll work, even if the listing says it's fine or whatever. A local trans shop manager told me that he once had some dude go through three junkyard trans and all were dead, and then he refused to pay the shop for labor because "the transmissions didn't work".

If you do end up buying a used trans somewhere, it may be worth it to install a shift kit while it's off the vehicle, and drain the torque converter of fluid. I believe there's one for our RE4R01A-HD that doesn't involve anything past removing the valve body, but I may be mistaken. It's meant to be able to be installed without removal of the transmission.

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CanuckQx4
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Well Ive been told by a local mechanic that my transmission is at the end of its life and should be rebuilt. So Im am looking to buy a used transmission and possibly try it if it gets inspected properly. Or possibly rebuild it.

I found this one on ebay, it says it came off a 2wd pathfinder 3.5L but says it isnt compatible with my 01 3.5L 2wd auto Qx4? Any reason for that or is ebay just wrong?

I want this specific one off ebay, they have good feedback and even a warranty, price is low, but the shipping costs as much as the transmission. About $325 total to my door
http://www.ebay.com/itm/02-PATHFINDER-A ... 5aeb11b2eb

What do you think??

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Towncivilian
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I'm almost certain the trans is identical. eBay is probably just wrong. See if the AT sections of the FSM for an 01 Pathfinder and 01 QX4 match, if they do there shouldn't be any differences.

Also provide your VIN, I'll see if the part number for the auto trans matches my 2WD Pathfinder part number.

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CanuckQx4
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The vin the salvage yard provided for the trans is JN8DR09X72W656546 and my vin is JNRDR09X01W203976

Having a hard time figuring a wat to confirm its fitment myself, thanks alot

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CanuckQx4
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Insurance put on the car for October 1st, I'll get to stretch its legs then. But Id love to know if I could/should buy that transmission

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Towncivilian
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I can't pull up that VIN with a Canadian version of FAST, are you sure JNRDR09X01W203976 is correct?

For the other VIN, the auto trans assembly part number is 31020-4EX79.

ddz0403
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Hey Canuck, I might have some news for you and lots of other owners with transmission shifting problems by tomorrow afternoon. I just pulled the control assembly out of my friends 01 QX4 yesterday and opened it up today. I found a sticky shift valve A and did a procedure on it to get it to not stick. I also did the same thing to shift valve B. I'm putting it back in tomorrow morning to see if there is any difference in the problem I'm working on - won't cold shift from 2 to 3 but works fine when warm. Look for a post this weekend. If it works I'll probably start a new thread detailing how I did it, without pics though because everything you need to know is in the service manual. Wish me luck.
BTW - this transmission was "rebuilt" only 10K ago.

Update - no joy here, back to the drawing board. The transmission doesn't even shift at all now. Pulling it apart again after it cools down and looking to see what happened....

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fueler
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Not sure how hard it is, as I paid a cheap mechanic to do it. I paid $1000 for a used junkyard transmission + labor. Not sure how much he sourced the transmission for, no idea how many miles it had. The guy told me it is a heavy transmission, and was a pain in the a** to do in his small shop.


100k miles later, the junkyard transmission still runs great, but i won't ever tow anything with it (towing too much weight while overheating destroyed my first transmission...won't make that mistake again)

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Towncivilian
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fueler wrote:100k miles later, the junkyard transmission still runs great, but i won't ever tow anything with it (towing too much weight while overheating destroyed my first transmission...won't make that mistake again)
You could always add one or two large auxiliary coolers and an in-line filter to help with that. Not that I would recommend towing over capacity, but even if you don't tow at all it will still help prolong the life of the fluid and transmission. I have a 19k GVW cooler (B&M 70268, though the thicker B&M 70264 is rated 24k GVW and will fit without a problem on an R50) and Magnefine in-line filter on my 2WD Pathfinder and I don't tow anything.

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CanuckQx4
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Towncivilian wrote:I can't pull up that VIN with a Canadian version of FAST, are you sure JNRDR09X01W203976 is correct?

For the other VIN, the auto trans assembly part number is 31020-4EX79.
That is definetely my Qx4's VIN according to my insurance paper I have sitting here. Maybe I'll verify that against the firewall in the morning.

Would really like to buy that trans, but dont want to gamble with it not fitting, appreciate the help :bigthumb:

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Towncivilian
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I don't know why I can't look up that VIN. I'll ask a parts dude to look it up for me.

ddz0403
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Got my transmission working. See my post about transmission morning sickness if you want. May not apply to you.

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Towncivilian
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Here are the priduction dates for the two part numbers. 'By the book' they are not the same.

31020-4EX79
R50 08/01-07/02
JR50 08/01-10/02


31020-4EX16
R50 01/00-08/01
JR50 01/00-8/01
Your QX4's trans is 4EX16. So the 01 Pathfinder's is newer. While it's not exactly the same part number I can't imagine there would be an issue, just make sure you get the TCM along with the Pathfinder transmission. But I'm not guaranteeing anything.

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CanuckQx4
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Im just going to pass on buying that particular transmission.

Really hard to decide what I should do here, getting quotes in the $2200 range for a rebuild on my stock one (including R&R) but Id really much rather buy a used good working one, and swap it myself even if it takes me a week!

Just not sure if I can pull it off without a lift and specialty tools

being 2wd definetely will help me!


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