I'm pretty sure it's my ISB considering the noise goes away after depressing the clutch. It's brand new, beck-arnely part I believe, and it's a bit disturbing. Luckily the new TOB is OEM Nissan. Thanks Gregg.

What else could it be?

 

So I was thinking about it today as I drove the Max around.

This noise, which can be diagnosed as a crummy input shaft bearing, started after 100 miles or so after I first put the 5spd in. I don't know it's history, and I just filled it up with Valvoline synthetic purple bottle stuff from autozone. I know I put the right weight in there.

Now, with a new ISB (timken part #108A), and 100 miles or so on it, the noise is back.

Does anyone have a clue why this noise came back so fast?

I suppose it could have been the bearing on the opposite end of the trans, or perhaps I need to put a shim somewhere?

I am going to drive it till something major happens, and probably try my hand at rebuilding the 5spd, or buying one from one of you all that is decent.

Thoughts? Remarks? Callous laughter? Anything is appreciated....

 

Is it an OEM tob? If not then that could be your issue.

 

It is OEM as far as I know. Am I correct in assuming it is the ISB creating the noise when the clutch pedal is up, and no noise when it is down?

I think that's what I have tried to lock into my memory, but that's all discretionary for what's it's worth...

 

Naw. Thats the TOB when its like that. ISB is gonna make noise regardless of where the pedal is. Only time it will be quiet is when bearing is replaced or car is off.

 

Maximo, sorry but that's incorrect. ISB will make noise only when the input shaft of the tranny is spinning. That happens any time the clutch is engaged (not on the floor), and any time the car is moving while in gear, whether the clutch is engaged or not.
If the car is stopped and the clutch is disengaged (i.e. stopped at a light in 1st gear) then nothing inside the transmission is spinning, and it will not make any noises.

TYPICAL input shaft bearing noises:
1. "growl" or whine in lower gears, worse when accelerating hard or decelerating. input and main shaft are not 100% aligned, so the gears aren't meshing properly, thus creating noise and wear on everything in the tranny.

2. light rattling while in neutral and clutch is engaged (pedal off the floor). the input shaft is spinning and basically flopping around on a bad bearing. same as above, but with no load on the shaft it's rattling instead of growling.

TYPICAL throwout bearing noises:
1. rattle while clutch is engaged (pedal not on the floor). try bleeding clutch hydraulics and check free play between the slave cylinder and release lever. You could also have something wonky in the release lever like the retainer springs or the TOB installed backwards on the lever.

2. squealing while clutch is disengaged (pedal on the floor). Typically caused by a bad or dry bearing.

Either of these parts can make noise while the transmission is spinning. sometimes time TOB will make noise only with pedal on the floor, sometimes only when pedal is up. it's fun to diagnose sometimes.

Most of these issues will require dropping the tranny to fix/check. your best bet at this point is to bleed your clutch hydraulics and check free play on the slave cylinder. If there's nothing wrong there, then you'll need to drop the tranny to check things out.

 

Ah, so it could be the TOB, and your description of these symptoms is incredibly valuable. That should be a sticky.

The noise I hear is noticeable at idle while sitting still. I can't really hear it while I am moving, but that's because of my exhaust noise. It is a lot like the sound of dried up, old bearings. No grinding or whining, just that special nasty bearing noise similar to what my wheel bearings sounded like before I replaced them.

It makes sense that it could be the TOB since I replaced the ISB and have used this TOB before and after the new ISB, but perhaps the internals were already a bit off and now that's causing the ISB to make noise.

I will check the hydraulics and the clearance between the slave cylinder and TOB lever. I never thought about how the TOB should be oriented on that lever, but I am pretty confident the retaining spring is mounted correctly.

How much clearance/play should the TOB lever have from the slave cylinder push rod?

I am probably not going to drop the tranny out for a while unless it is the misaligned gear assemblies. I'd rather save up and buy another rebuilt one before I try and drop this one and fix it. I learned my lesson too many times on transmissions in the past three years of rebuilding this car.

Thanks guys!!

 

Sorry Matt. Thats more of what I meant. I just chose the wrong way to describe it. Thanx for clarifying.

 

I had chimed in only because I had the same exact noise a year ago and thought it was the ISB. Turns out it was my TOB. After a tweek it shut up.

 

That sounds like it would be lovely. I shall try to fiddle with the slave cylinder here soon.

Is there a spec on how much clearance needs to be in between the push rod and the TOB lever?

 

basically zero clearance. the slave cyl should take up the slack as part of the hydraulic action- just like your brake pedal never gets lower as your pads wear.
If there's any slack in the parts, then there's something wrong- could be a bad slave cyl, bent clutch fork, bad TOB, don't really know until you start looking deeper.

IIRC, last time I pulled the tranny on my Max, I had to mash the pushrod on the slave cyl in about 1/4" to 3/8" before I could line up the bolts to mount it on the case. thus that's where you slack goes in the system. make sense?

 

Sounds good, I hope it's something slave cylinder related. Is there a simple way to test if my slave cylinder is out of whack?

 

You mean that striking pin in the slave that pushes against the fork? Thats always suppose to have some type of pressure as it is always against the fork. Even when you foot is off the pedal. Thats why you have to crack the bleeder valve (to relieve pressure) when your in the process of changing the clutch/ removing the trans.

 

I've never had to crack the bleeder valve to get the clutch slave on/off. just mash it up against the clutch fork with a few pounds of force, and it'll slowly push back as you pump the fluid back into the master cylinder. easy peasy.

But yeah, what he said otherwise.

 

What is this tweak you mention?

 

I accomplished this once and never could replicate it. Now I know. Guess I wasn't paying enough attention when I was doing it.

 

What I didn't at first (and probably you) is that the tob actually is suppose to click/ snap a lil when you install it to the fork via those lil metal clips on the back. Which might I also add go on a certain way (the lil hook is suppose to face the slave cyl/ facing right if your looking at it from the input shaft). The second thing that I kept forgetting about was that lil spring behind the fork that looks like a small deformed coat hanger. There are 2 slits on either sides of the fork where the notches on the arm of the spring are suppose to go all while the pivot ball run in between the springs 2 arms. At first it took me an hour to get it after cursing, stopping, pleading, etc. since then it only takes me 5 mins with the assistance of some needle nose pliers. Oh yeah! Use some needle nose pliers to assist or it take you an eternity. And that my friend is the tweak I did. Long story short things were crooked.

 

That sounds like fun! I am pretty sure I had all that stuff installed correctly, as I expect most things to click together and snap into place, but I am not 100% on my intuitive skills.

Oddly, the noise from the TOB has subsided for the day. I am gonna wait this one out as I don't wish to take the trans back off.......

Thanks for the help everyone.

 

Yeah. Just drive the noise out is another option. As crazy as it may seem I noticed mine subsided a bit after I drove it in my area a bit. I just couldn't wait and went in there myself to fully get rid of the noise.

 

It could be a wrong size, missing or damaged M/T input shaft bushing that fits in the flywheel....

 

Oh! You mean the pilot bushing. (kinda lost me for a sec)

 

Well, I think I may have a temporary fix for my noisy TOB.

I used my clutch stop sensor to push the clutch pedal in so far to pick up the slack in between the slave cylinder push rod and the TOB lever. Now it doesn't make noise and I don't believe I'm engaging anything to cause premature wear. There is no squish before I feel pressure building on the clutch pedal now, but I don't think it's doing any harm.

Though, I imagine ultimately the TOB needs to be replaced, ya?

Now that the TOB noise is gone, I can hear an intermittent noise coming from my water pump. It's kinda gnarly and off and on. I hope it doesn't fail catastrophically.....

Anyone need to tell me my clutch is gonna burn up or my TOB will melt with this setup before I try my first decent road trip this weekend?

 

You would know it prematurely engaged. Is your belt on too tight with that water pump? That could make that noise. Yes in the end you need to replace the tob. My clutch is stiff enough that I don't get any play when I push it. It will make your leg sore if your not use to it.

 

Ah ha, I could see how the tight belt would do that. It could also be the TOB transferring the frequency all the way through the engine, as it is pretty obnoxious.

I may put a longer spacer, via a longer bolt, as there is another half inch that would take the sound away completely, but it would make the distance between the the resting position and the friction point very short.

Is there any friction building before the clutch actually is engaged?

Thanks Maximo, you and a few others, you know who you are, keep this forum alive.

I wish I wasn't consumed with bicycles, scooters, and mopeds, or I would be all over my Max like I was when I got into this forum.......

I got my Max from my Aunt, who bought it brand new off the lot, and my other Aunt has a 93 Pearl GXE which they are giving me this year.

Maxima Family Love

 

If ur going through that much work then you might as well just replace the TOB. Same amount of work, but your not rigging anything to work.

 

That's a stretch, replacing the TOB is a female dog in comparison to what I did. All I have done is thread a bolt into the hole which typically holds the clutch safety switch, the one closest to the drivers foot. I thread it a bit too far earlier today and had some slippage, but it's good to go now.

I also loosened my water pump/power steering belt a bit and it seemed to help with some light chatter on that end.

Changing out the TOB? My god I don't want to go anywhere near that thing for a while, as the amount of labor and time would exceed what I have to offer these days. We'll experiment and see how long it stays the same. Once it shows signs of absolute degradation, I will probably park the car for another year before I build up the steam to knock it out. Ha!

I'm not saying my techniques are most effective or necessary, but in all reality, it'll buff out.

 

The more you do it the faster you become. Remember your eventually going to have to do it anyway. I use to be the same way, but was forced by my stubborn car to quite going against the grain. Once I conformed things became less frustrating.

 

So I just got back from a small road trip with my rebuilt engine and swapped 5spd. The noise coming from my transmission has gotten louder and more questionable to me. I placed a bolt in the clutch pedal bracket to depress the pedal enough to stop the noise while sitting in neutral at lights and such, but that caused some slippage while in 5th gear on the highway. I adjusted it so it doesn't slip, but the noise has gotten louder after my trip.

The concerning part of all this is that the noise is worst in low rpms, whether in gear or in neutral, and it has gotten worse in a short amount of time. I think someone in a post above mentioned the ISB creating noise in low rpms specifically, and would it make sense that it would make noise with the clutch pedal up as this would produce pressure on the input shaft?

I am having trouble figuring it out in my head as to what the exact cause might be. I replaced the ISB recently, but perhaps the bearing on the opposite end of the trans is done, and I should have shimmed it... I don't know what's what yet, and I would like to start saving up for a rebuild kit if I need to....

 

Well go ahead. Thought maybe it was the tob but if its isb then you got a job ahead of you. Either way you got to remove the trans for either one.

 

Does that sound like the ISB is bad?

I just replaced it, so I don't know. It's a good job indeed, at least I know now how to take it all apart and put it back together, but I seriously think something is wrong inside if the ISB is bad already.....

 

Well did you replace the other bearing you asked about? All I remember was when my tob was making noise it made this loud groaning noise. Something like if one were to roll ball bearings across a counter top just a a faster more consistent frequency. Usually that matches the engine rpms. When I pushed the clutch in it shut up. As soon as I slowly let out it slowly got louder.

 

I didn't replace the bearing on the wheel side of the trans as no one said it was a typical culprit...

I still think it is the TOB, but someone wmentioned the low rpm grumble being a typical ISB issue, but the noise does go away after pressing the clutch pedal down.

I may just go ahead and rebuild it, and I was wondering if anyone has any good references to a rebuild kit for a RSf50v?

Thanks for the help.....

 

Well if you'd like. I couldn't see myself going thru all of that when the culprit was a simple as a stupid tob.