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2002 R50 A/T with P0755 code. Please help!


RCAR50
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I posted in the R50 section, but got a bit long winded and no reply so I'll try again here and keep it short.

 

I am looking at a 2002 4x4 R50 with a 3.5 and A/T with just over 200K.

 

I got a P0755 shift control solenoid B malfunction code when I scanned it but I couldn't find much on the topic on this site.

 

It has a whirl or almost like a card in bike spokes sound coming from the transmission, present in all positions and becomes much louder when you shift into gears.

 

It will not engage into reverse at all. It will shift into forward gears and drive, I only went 20 mph though, didn't want to push my luck. It doesn't seem to be slipping at all, it will launch from a standstill somewhat impressively.

 

Any help would be greatly appreciated.

 

Thanks

Edited by RCAR50
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I don't think long winded was the problem--I can't speak for anyone else of course but I just don't know what would make that noise inside a transmission. I'd start with that solenoid code. Check the wiring on the off chance it's that easy, drop the pan, drop the solenoid, look for any obvious problems. If the solenoid jammed up while extended a little, maybe it's sending a little pressure somewhere it shouldn't and an accumulator or something is fluttering and making your baseball card noise? Hopefully fixing the problem the computer's complaining about fixes the noise as well.

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Thanks for the reply!

Ya, I plan to pull the pan and just tinker with the valve body and solenoids, check plug connections and the cables to the trans, change fluid and drive it home...hopefully.

If everything goes right I'll be bringing it home the 16th or 17th.

 

I'd like to swap in a M/T but that's above my capabilities at the moment. maybe later on if the truck holds up well enough.

 

any other ideas or suggestions...I'm listening.

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In the FSM the P0755 is this : TCM detects an improper voltage drop when it tries to operate the solenoid valve. Check harness or connectors (The Solenoid circuit is open or shorted) - Solenoid Valve B

 

Again according to the fsm, this solenoid operates with batterie voltage (12-14V)...

 

First thing I would do is verfy that the solenoid is working by applying voltage to it and listening to hear if it moves. if it does, from there I would trace the wire from the TCM to the solenoid. The cable is labeled L/R ( i guess light red ?) from pin 12 of the tcm side, it then goes through 3 connectors. I guess the easiest would be to test the cable at each connectors...

 

 

I'll try to put the fsm pages for you.

S.

 

** Update

 

The file is available for 90 days : http://wikisend.com/download/391266/p0755.pdf

p0755.pdf

Edited by fleurys
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Wow that is some great info! Thank you very much. I'll read through that and hopefully have a better idea of how to attack this issue.

The first thing I do to this truck after correcting the transmission issue is a set of your spacers. I never did lift my 96.

Still hoping to get this by the 16th.

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  • 2 weeks later...

Well I am picking this pathy up in a couple hours..

I didn't feel any slipping in forward gears so I'm planning on driving it home. I am thinking of connecting jumper cables to the battery from my Pathfinder when I shift it into gear hoping that it may just be a low voltage issue. I know it won't be that easy but won't hurt to try it..

I'll report tomorrow on how the drive home goes....

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Well the drive home went great!

Still no reverse, but it goes forward with almost no issues.

The drive was about an hour with the last 20 miles being a fairly steep incline.

The only thing wrong that it does in "D" make the whirling sound (similar to a rough blower motor sound) when you let off the gas. under load or acceleration it sounds fine. And when floored it jumps way up to about 7k rpm before downshifting, I let off before it went any higher.

Driving normal it did great... I'm not sure what the deal is, I'll be dropping the pan, looking for shavings, cause of fluid blockage and checking the solenoid as per Fluerys FSM suggestion.(thanks again for that info.)

 

Anyway this thing rode so nice, solid and quiet... Very happy with the purchase, even IF a trans is needed after all.

 

I'll keep the thread posted to hopefully help anyone else with similar issues.

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It might just be mine, but the auto tranny's in these things don't seem to be the smartest as to deciding what gear to be in when you floor it. Mine waits a second then shifts down, revs go extremely high, and sometimes it gives me a real hard time about shifting back into OD, especially if I'm going on a slight incline when I stop accelerating.

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This is my first experience with Nissan A/T.

 

On my way home on flat road, under light to normal acceleration it shifted at about the 4K mark, maybe 4300, it sounded like it was higher than that but I'm used to my 96s M/T.

On the highway doing about 60~65 it was running about 3500~3750RPMs.

I hit the O/D button a couple times and it didn't shift down, seemed to me that it never went into O/D.

Can someone who runs an A/T chime in here and give your shift points and highway Rpms.

I'll check my gear ratio in the morning, I know that will make a difference along with tire size.

Thanks guys!

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Yeah that's definitely higher revs than me. I have 32's so my numbers are a little low, but I cruise at 80mph with a little less than 3000 rpm. Trying to remember, I think it's about 2200-2500 at 70-75ish. I have the 3.5L and 4.363 gears.

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This is my first experience with Nissan A/T.

 

On my way home on flat road, under light to normal acceleration it shifted at about the 4K mark, maybe 4300, it sounded like it was higher than that but I'm used to my 96s M/T.

On the highway doing about 60~65 it was running about 3500~3750RPMs.

I hit the O/D button a couple times and it didn't shift down, seemed to me that it never went into O/D.

Can someone who runs an A/T chime in here and give your shift points and highway Rpms.

I'll check my gear ratio in the morning, I know that will make a difference along with tire size.

Thanks guys!

Just thought I'd listen into this topic , I've got an A/T transmission which isn't right atm with my O/D button , it's seems to be working but my Rpms can be high aswell . I feel safer pressing the 0/D on button just to drop another gear so it doesn't seem to feel struggling at about 80km/hr .

 

On the highway 12o km/hr my o2 Pathfinder sits about 2500 rpm that's with overdrive my car is feeling better with the O/D on .

 

 

Sent from my iPhone using Tapatalk

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I'd be surprised if a trans throwing a shift solenoid code wasn't running in some kind of limp mode. The WD21 locks itself into third and stays there. I haven't looked up what the R50 does, but I assume it would at least lock out OD. Good luck with the valve body!

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Thanks.

I don't think it's in limp mode, it definitely shifted from 1st to 2nd and then to some other gear that allow the drive home with nearly no signs of an issue.

I just hope I can get some type of answer while under it tomorrow.

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I didn't get a chance to open the tranny today, but I scanned it again and now instead of the P0755 it's showing a p0744... The other code is gone.

The fluid is very clean, almost clear but did smell a little burnt, not sure.

Not sure when I'll get a chance to open it, it's dark by the time I get home and I'm without a garage or cover from the rain....

Edited by RCAR50
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  • 3 weeks later...

Well... It took me long enough but I dropped the pan today.

First thing I noticed was a junk yard trans pan and the tranny is very clean compared to the block and t~case. Obviously been changed already.

The fluid was muddy and very burnt smelling.

The magnet is covered in metallic dust/sludge and there's a lot in the pan too.

The filter has it in there too and there were large pieces of debris in the pan.

I didn't pull the solenoids, but checked all wires and linkages and all looked good and were tight.

Not sure its worth it but I'm going to put in a new filter and fresh oil next weekend and hope for improvement.

I have pics to share but need to figure out how since the photobucket issue...

Any suggestions

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I'll try that site tonight..

Also as for the shift points I found my gear code is HG43 so it has the 4.363 ratio...

Edited by RCAR50
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  • 2 weeks later...

So I got a pic hosting site that's works (thanks trainbrain)

Here is what I found in the tranny pan... I was hoping the damaged seal was not allowing correct pressure but I wasn't that lucky... These are some large chunks of.... something...

 

CAUTION GRAPHIC IMAGES!

20171210_144914.jpg

20171210_150025.jpg

20171210_145945.jpg

Edited by RCAR50
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