03 fx45 trans issue

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IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

03 fx45 trans issue

Postby IronFistt » Fri Sep 20, 2019 7:12 pm

Hey guys,

I have an 03 fx45 with 221k on the clock. Just this week, the trans started acting funny. When i drive the car from a cold start, i have no issues. Once ive been driving around for a while, the car doesnt seem to shift down into first. So as you can imagine, when i take off from a stop, it takes forever to get any speed. Once I do get some speed going, everything is fine. Based on this, it might be time to do a trans fluid replacement (never done one yet) to see if that helps. The other thing is, when the trans starts acting like this, ive shut down the car and restarted it at a light and this seems to get the car back into first. So now Im thinking its not fluid but rather something else, sensor?

Anyone have ideas? Also, any instructions on how to replace the tranny fluid?


IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Tue Sep 24, 2019 7:09 pm

I also have a check engine light. My elm obd2 scanner kept saying no codes stored so i finally took it to autozone. They read the ecu and printed out P1759 and P1757. Searching around, it seems people are having issues with the valve body but Im hoping thats not the case for me. Also, Im read on the forums that theres no drain plug on this pan and ill need to drop the pan to change the fluid... however, i got under the car and there was a drain plug! I soaked the hell out of it with sea foam and the rusty plug came out fairly easy. Im using a 7qt drain pan and its mostly full from the drain but I think i read most people saying 4qts would come out, maybe misinformation similar to the car not having a drain plug.

Anyone do this and can speak to how much fluid came out? Im worried that 7qt is too much and perhaps coolant got into it. Also, when i do a fill, what fluid do you guys use? lastly, with 220 on the clock, im debating if i play with fire and attempt to pull the rusty pan to replace the filter

macgiver
Posts: 941
Joined: Wed Jul 04, 2007 10:21 am

Re: 03 fx45 trans issue

Postby macgiver » Tue Sep 24, 2019 7:22 pm

Someone preferably with experience needs to go the "distance" - drop pan ,assess particulate accumulaion,wipe & clean magnets and ALL pan surface , reverse blow screen or buy new (especially if sponge filter), while there test properly ALL accessible solenoids (especially ones related at all to 2-1 shift), RETORQUING ALL VALVE BODY bolts = a MUST (usually 10mm ,up to 30 of them) .

ALL that and fresh fluid is what in my opinion can be done , just before and just short of a rebuild .This job completion will be your "baseline" to decide to sell OR spend the $$$$$ BIG Bucks. :rotflmao

Double-Fistt that sucker on out of here , maybe ?? :confused:

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Wed Sep 25, 2019 8:33 am

So I went ahead and dropped the pan last night. Luckily, none of the rusty bolts gave me any trouble. The screen on the filter was surprisingly clean and the pan didnt have any gunk in it either. The fluid however was very dark and didnt have any appearance or smell of coolant (factory radiator holding up still). I brake cleaned the pan out along with the magnets and dried it all up and bolted in the new filter. It was already midnight and i didnt feel like pulling my first valve body so i left it alone. I got some trans fluid today that says its for matic J so ill toss that in but replace 1qt with lucas trans slip oil. Hopefully shes good to go on my quest for 300k!

macgiver
Posts: 941
Joined: Wed Jul 04, 2007 10:21 am

Re: 03 fx45 trans issue

Postby macgiver » Wed Sep 25, 2019 3:11 pm

Your well on your way ! Very curious I am , for learning what's what - if you may check those valve body bolts by hand , just being on the safe side , please let us know if those had gotten loosey-goosey ??
Respect , you went " the extra mile " by dropping pan / inspect / and clean - way to go !

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Thu Sep 26, 2019 2:26 pm

sorry, I didnt check any of the valve body bolts while i was in there... had i know that was an issue, i wouldve checked to see if they were snug. The bolts holding the filter were very easy to remove, i dont know the torque spec but they came out with way less pressure than the pan bolts. I thought there were only two sizes on the filter bolts but there is actually 3 (not including the nuts). So if anyone is removing them, keep that in mind so you can easily put them back in the correct place.

I havent put many miles on the car yet but I will say there was already a noticeable difference before i ever left my garage. Changing between gears (P, R, D, etc), previously the car would lurch into gear, now it slides in really smooth! Ill keep checking for leaks and fluid level. Hopefully this is the end of my trans issues

macgiver
Posts: 941
Joined: Wed Jul 04, 2007 10:21 am

Re: 03 fx45 trans issue

Postby macgiver » Thu Sep 26, 2019 3:58 pm

When those filter bolts ARE easy & loose is when the valve body bolts ARE easy & loose , for the info , next -time !
That's exactly what I was talki'n about :chuckle:

Good job though definitely , otherwise.

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Fri Sep 27, 2019 7:56 am

crap, not what what was hoping to hear!

I read somewhere on the net that the pan bolts are torqued down to 6 ft/lbs. With the car having lived through 16 chicago winters, it made sense that they were much harder to remove while the filter was exposed to no elements. I dont know the spec for the filter bolts but if similar, my highly calibrated sense of feel :naughty: says they were probably on par with 6ft/lb as that is not much.

I guess if i get into the situation where i need to drop the pan again, ill pick up or borrow a torque wrench that can go that low and see what its at..

macgiver
Posts: 941
Joined: Wed Jul 04, 2007 10:21 am

Re: 03 fx45 trans issue

Postby macgiver » Fri Sep 27, 2019 8:13 am

The spec should be easy to find , usually in INCH LBS . Inch pound torque wrench is MUCH safer than a Ft/Lb , to NOT go over.

A J30 valve body to case torque is 5 - 7 Ft/Lbs OR 60 to 84 Inch/Lbs , for example. Find YOURS.

If no torque "pattern" found , go tighten inside - out , move in a circular pattern on the way out to edge bolts. Break it into 'steps' - don't go full torque all at once on any bolts!! 4 or 5 steps good.

No real sweat - see how she runs for a while probly best and OK . :yesnod

EdBwoy
Moderator
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Joined: Tue Dec 25, 2012 12:47 am
Location: St. Louis Metro East - IL
Contact:

Re: 03 fx45 trans issue

Postby EdBwoy » Tue Oct 01, 2019 5:52 am

I'm a little late to the party, but it seems you've already done all the heavy lifting - good job! Now you can tell whoever said there was no drain plug to go sit quietly in the corner with the guys that say that you should never change the fluid in an "old" transmission.

You might have already figured this out, but I'll share some pointers for posterity.
The fluid you drain is typically 5 quarts, but will also vary depending on:
1. How the vehicle is tilted
2. How many components you disassemble (plug only vs. Dropping pan vs. Removing valvebody)
3. How long you allow it to drain
4. The temperature of the fluid when being measured
5. How much fluid the transmission had in the first place

Here are some videos:
1. How to measure quantity - https://youtu.be/QR1AV_jVxA8
2. How much to expect at draining - https://youtu.be/Nz5uhAEViUU

That being said, the codes you got are usually not merely "dirty fluid" codes, but if the fluid change has been working for you, it's all good.

***
I buy fluid from the dealer when servicing my vehicles for longevity. When troubleshooting issues, I prefer to spend a little less for fluid that might or might not be the issue - so I buy Valvoline Dex/Merc synthetic from either AutoZone (rewards) or Walmart (cost efficiency).
*I have found that this aftermarket fluid does not perform in any inferior way to OEM fluid.

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Wed Oct 02, 2019 7:28 am

The car has been driving great the last week or so until this morning. Upon startup, the "AT CHECK" light started flashing and I had downshifting issues again. It looks like ill be ripping the pan back off and dropping the valve body this time to replace the solenoids. Im assuming i dont have to remove the filter to get it off?

Checking amazon, i found this solenoid kit, does anyone know if its correct?
https://www.amazon.com/GooDeal-Transmis ... way&sr=8-4

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Thu Oct 03, 2019 6:08 am

I re-dropped the pan and took the valve body off last night. Macgiver, the bolts holding it in place were not loose at all. I guess the plan for today is to find time to take it apart and check the connections. I saw a bunch of youtube videos where they found broken circuits so ill look for that. Outside of that, im not sure what else to check? My original trans codes were:
P1759 A/T FR/B Solenoid Valve Performance
P1757 A/T FR/B Solenoid Valve Circuit Performance

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Wed Oct 09, 2019 9:29 am

Heres an update for anyone interested. After getting the valve body out, i pulled off all the solenoids and tested them. They ohm'd out within spec. I also applied 12v to the front brake solenoid and it was clicking just fine. I also tested the leads on the TCU that lead to the solenoids and they all ohm'd out so nothing was broken in there. At this point, everything seems to be in order, but for the hell of it, i pulled the TCU off the valve body to try and clean it. I couldnt pry the cover off to visually look at all the leads as I was scared I was going to break it. I was however able to pry it open slighly and hose it down with contact cleaner. Also for good measure, i ordered the solenoids off that amazon link and replaced 6/7. The low coast solenoid i didnt replace as that one is specific to certain year infitnitis and the one that got shipped was a general one for nissan.

Everything is back together and I took it for a quick spin last night. So far so good! Hopefully this thing is fixed for good now but I guess Ill know more after logging more miles on it. The only other thing I may do is add a dedicated trans cooler as a safety measure so that i dont end up with coolant in my trans in the future

luis_fx35
Posts: 2
Joined: Fri Oct 18, 2019 11:19 pm
Car: 2003 Infiniti Fx35 rwd

Re: 03 fx45 trans issue

Postby luis_fx35 » Sun Oct 20, 2019 7:56 am

Hi, I have a 2003 fx35 rwd and I was able to pry open the TCM and one of the leads, circuits or “buses” was actually broken and I took it to a computer repair shop where they soldered it professionally but it only lasted 3 months. I wish I knew how to solder this in a way that it wouldn’t unsolder again but I decided to buy a new valve body from Infiniti but when I called the parts department they told me that the valve body for my year model 2003 has been discontinued and my only way was to get a used transmission from a junkyard from a 2003 Infiniti Fx35 RWD and that it has to be same model year and rwd. At this point the only option I have is to send it to a company which remanufactures valve bodies for Nissan/Infiniti because they didn’t have a remanufactured one ready to send for my model year. When I went to Infiniti parts deal website and gave them my vin# it shows discontinued. My transmission was shifting smoothly when I soldered the TCM , so that proves that my transmission is still alive and the problem lies in the TCM where that broken lead, circuit or “buses” became unsoldered or broken the first and second time giving me false codes about a bad selenoid.
Keep us updated on what happens with yours.

IronFistt
Posts: 17
Joined: Sat Jul 02, 2005 12:17 pm
Car: 2003 Infitini FX45

Re: 03 fx45 trans issue

Postby IronFistt » Thu Oct 24, 2019 3:35 pm

Ive put on a couple hundred miles and so far so good. In your case, your valve body is fine and youre throwing away good money replacing it. Its the leads in the TCM that are the problem. Im assuming they dont sell the TCM separate from the VB? Im guessing the computer shop soldered the two broken leads directly together? If so, it probably wasnt strong enough to withstand the vibration and craked at the solder joint. One of the youtube videos i saw, the guy soldered in a jumper wire between the broken leads. Im assuming youll want to do something similar so that it withstands vibrations.

I think this is the video (too lazy to watch and verify) - https://www.youtube.com/watch?v=GAveITCubOQ


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