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Discussion Starter #1
Hi All

I’m new here and look forward to meeting some of you

Having recently purchased a Dodge Nitro 2008 2.8 which has no transmission on arrival

I purchased a replacement transmission and torque converter which is now installed it’s the Mercedes NAG1 different to the 3.7 and 4.0l transmissions I believe.

First question can anyone here tell me exactly how much transmission fluid the gearbox holds.. I’m told it’s 8.1litres from completely empty and 7.4 litres on a fluid filter service but I’ve since found a post stating it only requires 4.6 litres ????? I’ve even called main dealer and they wouldn’t say it’s a main dealer service.

Second question having installed the transmission I’ve noticed a problem I was driving at 40mph the car got to 2000rpm I accelerated and it dropped to 1800rpm and I couldn’t get the car to speed up I had to tap the accelerator to get it going it’s since done it twice more at 50mph I had to hit the brake and then accelerator to get it back to speed.

It’s done it twice on the same road oddly which is coming off a roundabout at low speed onto an incline 50mph road so requires a fair bit of quick acceleration.

I’ve since taken the car off the road concerned firstly is the fluid level incorrect, secondly the gearbox I bought is it or the torque converter faulty or ... does the transmission need to be flashed

Any ideas or help would be massively appreciated
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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Welcome to the forum Drew. When you have a chance, head over to the Newbie Section and say "Hi".
Tell us a little about yourself and your ride.
That way we can welcome you all proper like.

The NAG 1 is the same trany behind the 4.0 petrol Nitro.
See this thread; https://www.nitroforumz.com/threads/dipstick.32292/ Post 8.

According to the SM If only fluid and filter were changed, add 10.6 pts. (5.0 L) of ATF +4 (+/-).
If the transmission was overhauled or the torque converter was replaced or drained, add 16.3 pts. (7.7 L ) of ATF +4 (+/-).
 

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Discussion Starter #3
Hi ScarsO nice to meet you

I appreciate your reply :) il head over to the newbie section say Hi to all

Thanks for the information regarding the transmission fluid level ...

Do you have any idea why my gearbox isn’t engaging correct ..if my fluid is out it’s no more than 1/2 litre max ... could it be that installing a replacement gearbox that I need to get the computer mapped/flashed with updated software

Information in the UK is really not great for Dodge
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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What leads me to believe the trany may be low is your symptoms.
Going around a corner would cause the fluid to shift to one side in the trany. Over filling as well as under filling, can cause air bubbles in the fluid. The bubbles could cause the trany to go into limp mode.

As far as your question, Yes it is possible it needs to be programmed in the computers to function correctly. With a CRD and Nag1 there is a separate computer which controls the transmission (TCM). By separate I mean different then the PCM/ECM(Engine control Module).
In the 3.7 petrol, the PCM does both jobs.
What rig did the NAG1 come out of?
 

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Discussion Starter #5
What leads me to believe the trany may be low is your symptoms.
Going around a corner would cause the fluid to shift to one side in the trany. Over filling as well as under filling, can cause air bubbles in the fluid. The bubbles could cause the trany to go into limp mode.

As far as your question, Yes it is possible it needs to be programmed in the computers to function correctly. With a CRD and Nag1 there is a separate computer which controls the transmission (TCM). By separate I mean different then the PCM/ECM(Engine control Module).
In the 3.7 petrol, the PCM does both jobs.
What rig did the NAG1 come out of?
Yeah I thought as much myself to much fluid can cause the fluid to go foamy and to little means air being drawn into the pump right.. I had a real hard time of trying to get the information so really appreciate your reply there appears to be plenty of information out there for the 42RLE just not the Nag1.. the transmission came out of a like for like Nitro 2.8 mines an 2007 it came out of an 2008 otherwise it’s identical.
I can hear a slight whirring noise which first led my to believe the fluid must of been low

I guess retest fluid then next step is dealership to update the TCM

I did wonder if maybe it was the conductor plate plug or the plate as the rpm sensors are attached to the plate right

The previous owner said the original transmission just stopped dead and had no faults with the drive prior

Thanks
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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You are correct. Air bubbles and Trany fluid = not good things.
If it is from an 08 Nitro it should be OK program wise, But it may have a VIN mismatch error.
Yes, the speed sensors are on the conductor plate.
 

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Discussion Starter #7
I did wonder too if it’s matched to the vin number

I have the original conductor plate and transmission still which I could fit to my transmission really don’t want to have to take the car to a main dealer

I assume if I got hold of the TCM from the replacement transmission car it would still need to be coded to the ECU for my car
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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If the original conductor plate was bad, then you would be wasting time installing it in your current trany.
Correct. I know the TCM and ECM are Vin coded. Not sure if the conductor plate is...
 

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Discussion Starter #9
I don’t know that the original conductor plate is damaged from what I was told the car lost gears and the fluid was burnt

Hopefully it’s a case of the TCM needs coding the levels are correct and still I drove it today and once again it lost gears
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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If it is loosing gears, one would think you would be getting a CEL and pending/stored error codes.
 

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Discussion Starter #11
I’ve checked for pending codes and I’ve nothing I can only class it as the car going into limp mode for short periods

I’m thinking either a TCM flash I’ve read a little about the TCM learning your drive patten too

Do you know where the TCM is located??

Worse case scenario I’ve got the guy I
located the transmission from sending me the TCM free of charge incase mine is shot he’s adamanat the transmission was fine so has to be TCM,TCR, Conductor plate rpm sensor, Solenoid or faulty cable could you think of anything else I’ve missed ??

I’m trying to locate the fuse diagram for the transmission Relay has anyone got to hand to share please :)
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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Some codes only a dealer can access.
Without looking it up, I believe the TCM is on the left side under the dash.
The TCM from the other rig will do you no good as is. You will get a VIN mismatch error and it will not work. We had another member here with that problem.
At this point I would suggest getting a dealer diag. They can also run tests on the shift solenoids and all the computers.
 

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Discussion Starter #13
Checked the transmission for stored codes:

Had 5 codes present PO730/PO731/PO733/PO741/PO743

Wiped the stored codes drove the car and have since received a code PO741- Torque converter clutch circuit performance

I’m wondering could it be the torque converter not installed correct on the 2nd spline or ... the torque converter solenoid from what I can see the loom looks ok.

Defo thinking a trip to the dealership I have the original transmission still for parts solenoids etc thankfully
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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P0741 = Torque converter clutch (TCC) solenoid - performance or stuck off. Possible causes; Wiring, TCC solenoid.

P0730 = Incorrect gear ratio. Possible causes: Wiring, TR sensor/switch, shift solenoids, transmission mechanical fault.
P0731 = Gear 1 - incorrect ratio. Possible causes: Wiring, TR sensor/switch, shift solenoids, transmission mechanical fault.
P0733 = Gear 3 - incorrect ratio. Possible causes: Wiring, TR sensor/switch, shift solenoids, transmission mechanical fault.
P0743 = Torque converter clutch (TCC) solenoid - electrical. Possible causes: Wiring, TCC solenoid, ECM/PCM/TCM.

P0741 is set when the TCM detects more then the allowed amount of slippage, when the torque converter clutch is closed.
 
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Hey I'm still newer to this forum, I have a 2009 dodge nitro 3.7l and have been having tranny problems, first I got stuck in 2nd gear and wouldnt shift out. Let it sit an hour or so then drove fine for about 5 min then same thing happened. When I plugged my scanner in it came up with a code saying incorrect 4th gear ratio, I bought a new shift solinoid pack and put that in and made sure everything was done correct including the tranny fluid level. same problem is still happening, only now its saying 3rd gear incorrect ratio and now gets stuck in 3rd... any ideas? I dont have alot of extra spending money and would like to do the work myself.. any ideas what it could be. I appreciate it in advance... the code its throwing now is p0733 and new shift solinoid is still in
Thanks, Tyler
 

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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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Hey I'm still newer to this forum, I have a 2009 dodge nitro 3.7l and have been having tranny problems, first I got stuck in 2nd gear and wouldnt shift out. Let it sit an hour or so then drove fine for about 5 min then same thing happened. When I plugged my scanner in it came up with a code saying incorrect 4th gear ratio, I bought a new shift solinoid pack and put that in and made sure everything was done correct including the tranny fluid level. same problem is still happening, only now its saying 3rd gear incorrect ratio and now gets stuck in 3rd... any ideas? I dont have alot of extra spending money and would like to do the work myself.. any ideas what it could be. I appreciate it in advance... the code its throwing now is p0733 and new shift solinoid is still in
Thanks, Tyler
Was it a new one or reman/reconditioned?
 
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Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
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If not a mfg defect then that most likely leaves the wires. Check them closely around where they pass the exhaust going forward.
 
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