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2006 Nissan Sentra Spec-V
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22 Posts
Discussion Starter · #1 ·
I could really use some help diagnosing my transmission issue. It has me at a loss.
It's a 2006 Spec V. I've changed various trans. parts about 6 months ago. A new clutch kit, master and slave cyl., and a 2jr used transmission with a new shift fork. It has many more aftermarket and new parts all over, but that's all for the transmission recently.

The issue:
Trying to start the car... I push the clutch in, make sure it's in neutral, and turn the key. The car starts normally, no noises, vibrations or smells. When I let off the clutch (still in neutral) the car jumps forward like I've released it in 1st gear.

What I've tried:
I've tried a number of things and haven't been able to track down the issue yet. I've checked the linkage attached to the shifter and it looks good and moves freely. The other end of the linkage attached to the control assembly on top of the transmission, also appears to be moving in response to the shifter. I haven't found anything stuck, loose, or disconnected.

My clutch engages and disengages, since I'm able to idle as long as I have the pedal depressed.

With the car off, If I place the car in gear and try to roll it, it won't roll.
If I place it in neutral, I can roll it.
Yet, it seems neutral disappears and becomes an extension of 1st gear once the car is started...

I've checked and topped off the gear oil with no effect.

No related codes popping up, and no real warning or issues leading up to this. I drove it home and parked it, and this is what I have the next morning... Any thoughts on what I can check from here?

Extra details:
***
the only noteworthy things from the day before the issue began:

--I had just taken the car on interstate speeds (75-85mph ~30 miles each way) for the first time in months, but didn't notice anything "off" until the return trip. When I exited the highway, I noticed a very slight bit of trouble changing gears for the last 3-4 miles home. It didn't want to smoothly change, it took a second try as if I lazily, or too quicky changed gears without the clutch fully depressed. Wasn't enough to raise concern at the time. It struck me as an indication the gear oil was low or due to be changed.

--I was parked in 2nd gear on a flat driveway, and was lightly bumped from behind when someone else parked behind me. I didn't think much of it because it didnt leave as much as leave a spot on the bumper. I started it and drove 30 miles on interstate afterwards with no problems. Then parked it at home and here we are!
 

· The Watcher
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7,441 Posts
See if when you put it reverse if the reverse lights come on.

Pull the trans shifter input assembly, 4 bolts, and look at the shaft.

What weight oil is in there? I wonder if the detent springs have failed. It being in gear when it was bumped should have not caused any internal damage but I'm leading towards a fork being damaged.
 

· Banned
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Check your shifter cables. Unscrew your shift knob, pop up the shift boot surround, and take a look at the cables as you wiggle the shifter assembly. Have someone under the hood observing the other end of the shifter cables. That should fill in any blanks. You can also try and move the shift levers on the transmission yourself by hand. If you confirmed the transmission is in neutral with the levers, you have an internal failure and you should contact your insurance company since this is collision damage.
 

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2006 Nissan Sentra Spec-V
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22 Posts
Discussion Starter · #5 ·
See if when you put it reverse if the reverse lights come on.

Pull the trans shifter input assembly, 4 bolts, and look at the shaft.

What weight oil is in there? I wonder if the detent springs have failed. It being in gear when it was bumped should have not caused any internal damage but I'm leading towards a fork being damaged.
Thanks for the ideas.
The reverse lights do come on when it's put into reverse.

I have yet to pull the shift assembly. That's next on my list when the weather clears up. As far as the oil weight... I assume it's 75w85 or 75w90. I'd have to check with shop that did the transmission/clutch, though.

I did scour the fsm before posting here, and read thru that checklist. I had ruled out the wrong oil/level too high, just because I've driven it for the last 6 months with zero issues & I'm aware now of slow leak, so the level may be too low if anything. Which was my first thought, maybe it had gotten too low, then hot, and something seized or broke...
Is there anything in the fsm that outlines where/how to check detent springs? My ability right now is limited to diagnosing/repairs without needing to pull the transmission. As soon as I start creeping into that territory, I'll have to turn the job over unfortunately.
 

· Registered
2006 Nissan Sentra Spec-V
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22 Posts
Discussion Starter · #6 ·
Check your shifter cables. Unscrew your shift knob, pop up the shift boot surround, and take a look at the cables as you wiggle the shifter assembly. Have someone under the hood observing the other end of the shifter cables. That should fill in any blanks. You can also try and move the shift levers on the transmission yourself by hand. If you confirmed the transmission is in neutral with the levers, you have an internal failure and you should contact your insurance company since this is collision damage.
I've inspected the linkage at both ends, in the car and under the hood. Everything is connected and moving. When the shift lever is used in the car, the control assembly and linkage under the hood lift, twist and fall normally and vice-versa. I can manually move the control assembly under the hood by lifting and turning it, and the shifter in the car moves itself into gear as a result. I can put the shifter into neutral, whether I'm using the shifter or manually doing it under the hood. Then try to start the car and it acts like it was still in gear, unless I'm actively pushing the clutch pedal down.

I appreciate the help. It's starting to sound more and more like a sudden internal failure
 
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