2002 Infinity Q45 Transmission

[Gito]

2002 Q45 with 250k miles

Experiencing hard shift between 1st to 2nd gear. Car is now at a Transmission shop. Tech said that the transmission is not throwing out any codes. Was told by tech that the cars transmission acts one way when it's warm and acts another way when it's cold. I believe the tech said that when it's warm the shifts become very erratic.

The shop thinks that it's the control module (part #31036AR160) and such module is no longer available thru dealer. They told me that they are going to drop the pan an going to evaluate the oil. They want to hold off on the module for now until they check the condition of the transmission fluid. The tech mentioned that if needed, eBay may be the only source for the control module.

Any advice is greatly appreciated

 

[SirTanon]

250,000 miles.. If the transmission fluid has never been changed, then I could see it being the root cause of ALL of your problems.

If it has, then another possibility could be one or more of the sensors inside the trans.. input speed, output speed, etc..

 

[zorobabel]

On the Maxima there is a resistor that, when bad, can cause that behaviour: https://maxima.org/forums/4th-gener...-gen-transmission-resistor-must-do.html. This is a Jatco transmission.

 

[CBR.worm]

I don't know for sure, but I would imagine your car uses some variety of the Jatco RE5R05A, that transmission is/was used in most RWD Nissan and Infiniti cars and trucks with 5 forward gears and RWD/AWD. It is supposed to be a fairly reliable unit capable of holding a decent amount of torque - except in the Titan and Armada, which I understand had cooling issues. I also understand that transmission techs that don't have experience with its quirks tend to have a hard time. There are many things that can cause it to behave differently when hot vs cold, both electrical and mechanical. A shop with experience with these can watch the realtime data and get a pretty good idea of what is going on. These are adaptive transmissions that monitor ATF and engine coolant temperature as well as line pressure at multiple points and RPM of turbines and many gears, throttle position, brake light state, even A/C operation. There are many sensor readings that could be flaky enough to cause driveability issues without triggering the AT light or CEL In my limited experience, shifting hard is better than slipping and ruining the remaining friction surfaces.

You may need to take the car to a shop that specializes in 350Z/G35/G37 cars or possibly a shop that specializes in Nissan/Infiniti trucks. Someone who will have had lots of experience either building these to handle more power, or repairing them after someone cooked them at the track or in the mud. Maybe this guy is one of them?

250K isn't a bad life out of an auto transmission behind a high RPM 350hp V8 in a heavy car. I'm a couple of years from that mileage, and I'm already trying to get an idea of who will be able to work on it when it breaks.

 

[Gito]

Originally Posted by zorobabel
On the Maxima there is a resistor that, when bad, can cause that behaviour: https://maxima.org/forums/4th-gener...-gen-transmission-resistor-must-do.html. This is a Jatco transmission.


where would I find the resistor on a 2002 Infinity Q45? Is there a schematic available online? Sounds like something worth trying before trying the module swap

 

[CBR.worm]

Here is the service manual for that car: https://www.nicoclub.com/FSM/Q45/2002_Q45/2002_Q45/

The index is idx.pdf

 

[Gito]

Trying to locate the resistor part number because I'm not able to find it on the schematic.
I called Infinity and told them that I needed a transmission resistor. Sales guy had no idea of what I was talking about.

Anyone have experience with this part (transmission resistor) on a 2002 Infinity Q45?

 

[clinebarger]

My sources show NO dropping resistor for your RE5R05A like the RE4F04A found in 4th gen Maxima's.

I know just enough about JATCO units to be dangerous

.......I would have the Line Pressure checked with a mechanical gauge FIRST!!! This is a basic fundamental of transmission diagnostics that seems to be lost on technicians today.

My limited experience with these units revolves around coolant contamination from failed coolers....We would just swap them out with low mileage take-outs.

 

[Gito]

Originally Posted by clinebarger
My sources show NO dropping resistor for your RE5R05A like the RE4F04A found in 4th gen Maxima's.

I know just enough about JATCO units to be dangerous

.......I would have the Line Pressure checked with a mechanical gauge FIRST!!! This is a basic fundamental of transmission diagnostics that seems to be lost on technicians today.

My limited experience with these units revolves around coolant contamination from failed coolers....We would just swap them out with low mileage take-outs.





The transmission shop called and told us that due to age alone the transmission should be rebuilt if we are planning to keep the car.
The techs were honest and pretty much said that it could be the control module or it could be the transmission that is causing the issue.

The shop wanted to drop the pan to check the oil but I told them that the car had been pretty much hard shifting for some time and the transmission fluid was replaced 3 months ago.

No charge and back to square one.

 

[Gito]

Originally Posted by CBR.worm
I don't know for sure, but I would imagine your car uses some variety of the Jatco RE5R05A, that transmission is/was used in most RWD Nissan and Infiniti cars and trucks with 5 forward gears and RWD/AWD. It is supposed to be a fairly reliable unit capable of holding a decent amount of torque - except in the Titan and Armada, which I understand had cooling issues. I also understand that transmission techs that don't have experience with its quirks tend to have a hard time. There are many things that can cause it to behave differently when hot vs cold, both electrical and mechanical. A shop with experience with these can watch the realtime data and get a pretty good idea of what is going on. These are adaptive transmissions that monitor ATF and engine coolant temperature as well as line pressure at multiple points and RPM of turbines and many gears, throttle position, brake light state, even A/C operation. There are many sensor readings that could be flaky enough to cause driveability issues without triggering the AT light or CEL In my limited experience, shifting hard is better than slipping and ruining the remaining friction surfaces.

You may need to take the car to a shop that specializes in 350Z/G35/G37 cars or possibly a shop that specializes in Nissan/Infiniti trucks. Someone who will have had lots of experience either building these to handle more power, or repairing them after someone cooked them at the track or in the mud. Maybe this guy is one of them?

250K isn't a bad life out of an auto transmission behind a high RPM 350hp V8 in a heavy car. I'm a couple of years from that mileage, and I'm already trying to get an idea of who will be able to work on it when it breaks.

Originally Posted by CBR.worm
I don't know for sure, but I would imagine your car uses some variety of the Jatco RE5R05A, that transmission is/was used in most RWD Nissan and Infiniti cars and trucks with 5 forward gears and RWD/AWD. It is supposed to be a fairly reliable unit capable of holding a decent amount of torque - except in the Titan and Armada, which I understand had cooling issues. I also understand that transmission techs that don't have experience with its quirks tend to have a hard time. There are many things that can cause it to behave differently when hot vs cold, both electrical and mechanical. A shop with experience with these can watch the realtime data and get a pretty good idea of what is going on. These are adaptive transmissions that monitor ATF and engine coolant temperature as well as line pressure at multiple points and RPM of turbines and many gears, throttle position, brake light state, even A/C operation. There are many sensor readings that could be flaky enough to cause driveability issues without triggering the AT light or CEL In my limited experience, shifting hard is better than slipping and ruining the remaining friction surfaces.

You may need to take the car to a shop that specializes in 350Z/G35/G37 cars or possibly a shop that specializes in Nissan/Infiniti trucks. Someone who will have had lots of experience either building these to handle more power, or repairing them after someone cooked them at the track or in the mud. Maybe this guy is one of them?

250K isn't a bad life out of an auto transmission behind a high RPM 350hp V8 in a heavy car. I'm a couple of years from that mileage, and I'm already trying to get an idea of who will be able to work on it when it breaks.


Sure sounds like I need to find someone who knows these transmissions. Been on a few other forums and not getting anywhere with this issue.

 

[bblackmon19]

Sounds like the accumulator control spring is broken, other Jatco transmissions would break them very early in their life causing hard 1-2 shift. It wont hurt the transmission but you will feel the shift.
It will also seem to come and go with temperature and rpm differences.

 

[Gito]

Originally Posted by bblackmon19
Sounds like the accumulator control spring is broken, other Jatco transmissions would break them very early in their life causing hard 1-2 shift. It wont hurt the transmission but you will feel the shift.
It will also seem to come and go with temperature and rpm differences.


Where is that spring located? Internal or external?

 

[clinebarger]

Originally Posted by Gito
Originally Posted by bblackmon19
Sounds like the accumulator control spring is broken, other Jatco transmissions would break them very early in their life causing hard 1-2 shift. It wont hurt the transmission but you will feel the shift.
It will also seem to come and go with temperature and rpm differences.


Where is that spring located? Internal or external?


The RE5R05A has NO Dynamic Clutch Accumulators......
It has 2 Reverse Clutch (Park/Neutral to Reverse) Accumulators & a Front Brake Clutch (Neutral to Drive) Accumulator....These control the "Garage Shifts" Park/Neutral to Reverse & Neutral to Drive.

The Direct Clutch is the Dynamic member for the 1-2 shift, Harsh 1-2 shift possible causes per Nissan.....

 

[clinebarger]

Of coarse Nissan doesn't take into account a 250,000 mile unit as they don't have to warrant or otherwise take care of your complaint on such a high mile unit......If they did, I'm sure they would include "Excessive Direct Clutch clearance" in the possible causes!

It's a basic fundamental of transmission operation, The further the Apply Piston/Servo Piston has to move to actuate the Clutch/Band......The more speed they build & harsher apply/feel will result.

I'm sure the logic in the TCM has Adaptive Strategies to keep shift feel the same throughout the life of the unit, But can be counter intuitive to an actual mechanical issue.....It will RAISE line pressure in the attempt shorten the "shift time". This will only magnify the shift concern!

Mechanical Holding Member chart.......I added a arrow for the Direct Clutch coming on for the 2nd ratio.

 

[Trav]

Hang on, there will be a you tube video up soon with a full authoritative explanation as to what went wrong and how to fix it. LOL

 

[clinebarger]

Originally Posted by Trav
Hang on, there will be a you tube video up soon with a full authoritative explanation as to what went wrong and how to fix it. LOL

 

[CBR.worm]

Mine is an '06 and I can monitor line pressures at multiple points as well as see what solenoid actions are being requested and the results (as read by sensors, which may be working), but there is enough real-time data through a consult II interface, that a tech with the proper tools should be able to 'see' what is going on while driving test patterns.

But, again, at 250K miles, it is unlikely that a more drastic failure is not in the cards. If it is a TCM or Valve body, even if you can get by with a less expensive fix at this time, that money could probably be put towards a more permanent fix. If it is an external sensor, you may be able to get away with an inexpensive fix to get you some more miles.

Since I have a slightly newer VK45DE powered vehicle with a newer version of that transmission with 180K miles on it, I'm curious what unexpected powertrain issues you have run into in your 250K miles? So far for me, it has been an engine fan that was coming apart and a differential bushing that leaked all its goo, valve cover gaskets and the odd vacuum hose. And a cam position sensor. I use mine to tow quite frequently and I usually drive it like a racecar (but only once it is hot). I'm interested to see how long it will last.

Right now I have my first front end clunk which I have not yet diagnosed.

 

[Gito]

Had to reluctantly take it to the dealer (125$). In the end the dealer said that they could not communicate with the computer.
They said that the cars transmission is no good and they based it on the mileage and the appearance of the ATF on the dip stick.

I picked up the car and drove it home.
I'm going to check the ATF tomorrow and see whats going on.
Going to drain if the ATF looks bad and refill using the Nissan Matic S.

The first shop I took it to wanted $175 to drain and check the condition of the fluid.
I didn't want to cough up that much money for a drain and refill so I picked up the car and told them no thanks.
Well I ended up coughing up $120 at the dealer and nothing was done other than pulling the dip stick out. Jeez
Would of been better off paying the $175 at first shop but I thought that the dealer techs could figure something out.

I bought this car for my parents in 02' and they pretty much were the ones taking the car in for the maintenance and servicing.
I asked them when they last replaced the transmission fluid and they said they took it to Jiffy Lube 8 months ago.
Not good because I doubt the right ATF was used.

Called around and found a shop that was able to find a used transmission that has 69k miles on it.
$800 for the transmission and $450 for labor. Might have to go this route but I'm worried that the car might have a bad control module.

 

[clinebarger]

What happened to honesty & integrity? The service writer KNEW they would blow you off in the end.....So WHY take the vehicle in??

 

[Gito]

Originally Posted by clinebarger
What happened to honesty & integrity? The service writer KNEW they would blow you off in the end.....So WHY take the vehicle in??


Parents can't remember exactly when the transmission fluid was replaced. Father says 3 months ago and my mother says 8 months ago.
I asked them if they have a service receipt/invoice and they can'f find one. One thing that they both agree on is that Jiffy Lube was the last place that replaced the ATF.

Parents thought that it was best to take it to dealer because they thought the Service manager was really nice and honest. I reluctantly had to take it in to please them.

Back to square one