# Grinding / vibration problem. Thump when backing up.



## rodentkj (Mar 8, 2005)

1992 Sentra SE
1.6L
5 Speed Manual
OK. Let me first explain what the symptoms are.
1.When in reverse, the motor or trany is thumping against the frame. To me, it sounds like noise is coming from the right front. Somewhere in the area where the trany meets the engine.
2.The motor has a lot of movement in it. When accelerating or coasting there is a clear grinding noise. Grinding may not be the best word to describe it but it almost sounds as if it's a bearing gone bad. The motor has, what seems like to me, a lot of forward and back movement. I can feel it move forward and back in the shifter. And when the motor is under a load, either forward or back, I hear this "grinding" noise. It's very load when in gear coasting downhill. However, when going down a small hill, the motor seems to find a sweet spot and the sound goes away. But as soon as the motor bounces front or back, that noise happens with each bounce.
3. When downshifing, the motor and trany will vibrate and or shake like crazy. This problem seems to be getting worse as the weeks go by.
4.Car pulls slightly to the right when accelerating. Seems to pull more when under more of a load.
5.Small clicking noise coming from the left front side. Changes with the speed. Can only really hear it when out of gear, coasting at slow speeds.

Here is what I have done.
1. Replaces the right front transaxle. Made no difference.
2. Replaced all 4 motor mounts. The rear mount that is on the main support is a real pain. This seemed to make the thumping noise in reverse worse. But did not make a change to any of the other issues.

I'm not sure if I am dealing with more than one problem or not. When replacing the rear motor mount, I did notice that there is some type of bar attached to that mount that runs next to the exhaust to the back of the car. What is that bar? And could it have anything to do with this issue?


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## Oldnissanguy (Jan 6, 2005)

If the clicking is on the left side why did you replace the right axle? Was there something wrong with it?


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## rodentkj (Mar 8, 2005)

Correction. I replaced the left transaxle.


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## rodentkj (Mar 8, 2005)

Someone?? Anyone??


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## 92se5speed (Aug 22, 2006)

Sounds like exactly what my trans started doing this morning. I think my differential is shot, I'm just going to put a new transmission in. Probably what you need to do also.


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## rodentkj (Mar 8, 2005)

92se5speed said:


> Sounds like exactly what my trans started doing this morning. I think my differential is shot, I'm just going to put a new transmission in. Probably what you need to do also.


Uggg.. Don't say that....


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## 92se5speed (Aug 22, 2006)

Strange thing is, my car went from absolutely perfect to totally wasted in the span of 2-3 miles. I have no idea what went wrong, but my trans is getting pulled out tonight. Luckily I have experience with this, I recently bought a 92 XE that needed a clutch (sold the car over the weekend). Not all that bad of a job, just sucks getting the trans back off the floor and lined up with the engine. 

Hopefully I find a cheap trans from a local junkyard, going from 31 mpg in the sentra to ~17 mpg in my old van for commuting will definitely suck! 

Where you at? Let me know if you need any help / tips on changing out that trans.


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## rodentkj (Mar 8, 2005)

I'm in the seattle area.....

Well, mine has been getting progressivly worse over the last several months. First thing I need to figre out is why the hell the engine is bouncing back and forth so much. It's so bad than when I'm moving slow in 1st gear and if I let off on the gas the engine will bounce so much that it's clunking on something..... I just can't figure out what's bad.


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## 92se5speed (Aug 22, 2006)

Got my trans out and apart this weekend. My original plan was to get a used trans from a local yard and swap it in... unfortunately, looking like no one around my area has one, and they've quoted "about $450" if they call other yards and get one shipped in. SO, my father-in-law figures we can fix mine, shouldn't be too bad since he's a Nissan mechanic of almost 20 years, so he knows what he's doing. 

I'm not really sure what exactly failed, but the bearing on the end definitely took a sh!t, and the large output gear is pretty chewed in a few places. Check it out. Good luck with yours!


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## 92se5speed (Aug 22, 2006)

Something tells me my car is going to look like this for a while...


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## mrgoose (Sep 13, 2006)

Wow, awesome pics. I've never seen inside an old transmission like that before. Really interesting, thanks for posting!


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## 92se5speed (Aug 22, 2006)

Glad to oblige... if only it wasn't at the cost of me having no car for probably a month. Ah well, my trusty Caravan is getting me around now. Just sux to be getting 18 mpg instead of 32.


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## 92se5speed (Aug 22, 2006)

So the Sentra is back on the road, sorta. I had no luck finding a cheap used trans that was already pulled, so this weekend I pulled a trans out of this beast in the self-pull yard:



















The fact that it came out of a 95 was no problem, it went in my 92 fine. There is indeed another sensor on the trans (right on the front of it) but I just left the sensor in the hole. 

I was a bit worried since it appeared the donor car was in a demo derby or something, but it seems to shift and work nicely. Unfortunately, on my 1 mile test drive, my throttle cable frayed at the firewall and ended up sticking my throttle open. Had to shut the engine off, force the throttle shut, and idle home. Of course, it's an item you can't exactly get down at Autozone, so my dad is checking at the Nissan dealer if he can get one, otherwise it's back to the junkyard. 

rodentkj, what ever happened with your trans? Turned out the main failure with mine was the bearing at the end of the output shaft took a crap, then the shaft flung around and destroyed the end of the trans case. I think the fact that it could move around so much is what caused the rest of it to get chewed up. Good luck with yours! If you were anywhere close, I'd gladly help you put a new one in... I'm a bit of an expert now.


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## Oldnissanguy (Jan 6, 2005)

Hope you have better luck than me on finding a used cable. I had to buy a new one from the dealer. They're not cheap.


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## 92se5speed (Aug 22, 2006)

Throttle cable fixed... $4 at the junkyard, like-new condition. Feels good to finally be back in the Sentra!


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## rodentkj (Mar 8, 2005)

92se5speed said:


> checking at the Nissan dealer if he can get one, otherwise it's back to the junkyard.
> 
> rodentkj, what ever happened with your trans? Turned out the main failure with mine was the bearing at the end of the output shaft took a crap, then the shaft flung around and destroyed the end of the trans case. I think the fact that it could move around so much is what caused the rest of it to get chewed up. Good luck with yours! If you were anywhere close, I'd gladly help you put a new one in... I'm a bit of an expert now.


We. I have been driving it the way it is. However, today it made some really bad noises when grabbing 2nd gear. I think something is about to fail. So, I did some checking and I fould a tranny local in the area for 395.00. So, I'm going to replace it this coming weekend.

My main concern is that because the motor is jumping around in the engine compartment, which I can figure out way, caused this problem. So if I don't fix that issue, I am worried it will happen again to the new tranny.

I wish I had the knowledge you have. I got a feeling it's going to be a long wekeend.


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## mrgoose (Sep 13, 2006)

Maybe this sounds naive, but if your motor/trans mounts are good, shouldn't they prevent the motor from jumping around too much? My understanding is that excessive motor/trans movement is often caused by bad mounts.


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## rodentkj (Mar 8, 2005)

mrgoose said:


> Maybe this sounds naive, but if your motor/trans mounts are good, shouldn't they prevent the motor from jumping around too much? My understanding is that excessive motor/trans movement is often caused by bad mounts.


One would think that, but I replaced them all. It did not help at all with the motor jumping around in the engine compartment.

I've asked about ths before but never got any answer. But there is a bar that runs next to the exhaust. If I remember correct, it connects in the area of the rear mount. An by rear mounts I mean the large round mount that is on the main cross member right on the firewall. Anyway... This bar which runs next to the exhaust seems to have a rubber bushing on one end. I can't see the other end as it seems to be that the other end is covered by the shields that run along the exhaust. I would have to assume that the other end has some type of rubber bushing/absorber also. From the design, this bar seems to add stability so the motor does not move forward and or backward in the engine compartment. e.g. it adds rigidness when power is applied and or removed. So I need to look at this bar as for I am thinking that maybe something is wrong on the other end and it's not giving the stability it should.

Anyone know what bar I am speaking of?


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## mrgoose (Sep 13, 2006)

Oops! Looking back at your original post you already mentioned the mounts.

Well, your question is beyond me. I've never played with the rear mount. Good luck!


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