Here is the problem. I have just finished my engine/transmission swap. As I finished the initial engine break in run (15 min at 1500rpm) a loud squeal started. I couldn't isolate the source then. Felt it might be an alternator bearing or the throwout bearing. After the engine cooled and I changed the oil and filter, I started it back up, no squeal for about 5 minutes then the squeal begins again, starting soft and getting louder. I changed the throwout bearing, started it up and in 5 minutes the squeal begins. It is definitely coming from the front of the transmission not from the front of the engine. It must be the bearing(s) on the input shaft of the transmission. The tranny is new (GM version). I bought it from Precision Gear. What I need to know is what is involved in changing out the bearings. Are special tools required or can a person with fair mechanical skills do the job?

Are you sure it is not the pilot bearing or bushing?

I don't think that it is the pilot bushing. The bushing is brass and soft compared to the steel. I checked the tip of the input shaft when I changed the throwout bearing. It had grease on it and did not appear to have rubbed on anything. I did not pull the bell housing and clutch to examine the bushing after I looked at the input shat. I also put more grease on the shaft tip and bushing when I reinstalled. I wouldn't mind it if it were that easy to fix though.

Just to make sure I would pull off all of the belts and see if it makes noise.

After it starts to make noise and you shut the motor off can you feel any heat from the front of the tranny. With the inspection cover off can you put your hand up near the input shaft and feel if the bearing retainer is warm.

Yep, pulled the belts off, not from the front. I can't reach the bearing retainer. The AA bellhousing isn't designed that way.

Does anyone know of a book that details the NV4500? One with big pictures?

Installed a new crate NV4500 in the CJ Outback Challenge CJ (http://www.northern4x4.com/events/OBC/OBC.htm) With in a week the front output bearing started to growel. Talked to the supplier, and wouldnt you know it, they had a stack of them sitting on the shelf,, Almost like they knew someone might call for a front bearing on a brand new tranny....Hummmmmmm, anyway... Upon inspection it was found not to be tha bearing, but the way it was installed, the front cover was cocked due to inproper shimming. Fixed this and the noise went away... We still have the spare bearing, incase, but it seems to have fixed the noise.

Edit, cuz I spel lik shet

Thanks Bronco78 I will look at that to see if it is the problem. I don't think it is though. Couple of reasons, when I was installing release bearing device from AA over the front output bearing cover, I did pay real close attention to it. It appeared to be well installed. The reason that I don't it is the cover is the difference in sound. This sucker isn't growling, it is friggin screamin in agony.

BTT

Pull the fawker apart.

I mean how hard can it be. Its a manual tranny.

Ron

hey might try running it for a while
soner or later you will be able to tell what is wrong.

This May sound like a stupid question BUT
does it make the sound with the clutch pushed in??

and cant you get a pilot bearing instead of
a bushing??

Originally posted by Land Crusher
hey might try running it for a while
soner or later you will be able to tell what is wrong.

This May sound like a stupid question BUT
does it make the sound with the clutch pushed in??


This is a good point. With the motor running, the tranny in gear,
the clutch pedal pushed in, nothing in the tranny should be turning.

Drive it till something falls out...Thats your bad part (or one of em)!

"Drive it till something falls out...Thats your bad part"

On a POS junkyard $50 tranny that is a good idea. On a NEW NV4500 that is a really BAD idea.

Ron

It's a bad idea on any tranny, but all the good answers were taken, so I settled for the funny one.....:flipoff2:

It could be a thrust clearance problem between the Input gear and the tranny mainshaft......... was there any binding on thetranny adapter (that might have pushed the mainshaft forwards..)
It could also be the pilot rollers between the tranny mainshaft and the input gear...I would pop the top cover off the tranny and check the inut gear/mainshaft alignment (after checking with your vendor to make sure this won't void any pending warranty claim...)

Ok, went out and warmed it up till the screaming starts, takes 5-7 minutes. Put the clutch in, less screaming but still there. Put it in gear, clutch in, still there, but not as loud. When the noise first starts, moving the clutch or putting it in gear has more of a quietening effect, but as the scream get louder the clutch and gears have less and less of an effect. Doesn't sound like it is coming from the engine, but I guess it could be. The engine is a new ZZ4. This really has me stumped, any ideas would be appreciated.

Well, it could be really bad....:( Here are my thoughts.

When the clutch is in, the tranny does not spin.....noise still there, not the tranny.

Clutch out, tranny in neutral. Flywheel is turning the pilot bushing same speed as tranny input shaft....noise still there, not the pilot bushing.

Could be something as simple as the clutch adj is too tight and the through out bearing is riding on the release levers in the pressure plate. I would take the clutch rod off and pull the fork forward and bungee it. Make sure the bearing is for sure off the plate, then try it.

Or, it could be something more serious like the crankshaft thrust bearing clearance is too tight and it is tearing up the thrust faces on the crank/bearings. Have you drained the oil yet, there may be a tell tale sign in the bottom of the pan......:eek:

Thanks to all that have tried. Yes I did all of the things you suggested Keith. I pulled the transmission this afternoon and ran the engine without it. As before at around 5 minutes the squealing starts. It is coming from the back of the block somewhere. I think you may be right Keith, the thrust bearing clearance must not be correct. I guess I will have to wait till Monday and start the claims process with Chevrolet. I'll bet I'm screwed though. The engine was delivered the first of last May and was just waiting for me to finish everything else on the buildup. It doesn't have 1 hour of run time on it yet. Time for lots of :beer: :mad: :mad: :mad: :mad: .

OMG! That sucks.:mad: Were you able to pre-oil the engine before startup? Sounds like a long time to sit. The thing that makes me think it may be the thrust bearing is that the tone changed when you pressed the clutch. GM will probably try to tell you that you had an improperly adjusted clutch, and the throughout was riding on the plate. They will say it caused enough pressure to push the crank forward with enough force to wear the thrust surfaces on the crank.
May be worth the trouble to pull the pan, oil pump, and the rear main cap to get a peak at the bearing. Got to be some serious metal to metal contact to get it to shreek the way it does. Whole thing sounds like a HUGE bummer though.:mad3:

Yep, pre-oiled it, for 1 minute, about 20 minutes before I started it for the first time. The throwout was never riding on the plate. I spaced according to Centerforce instructions, 1/16" clearance between the throwout and plate. Everything on this beast is new. Engine, flywheel, pressure plate, clutch disc, throwout bearing(2),...... I have worked very closely with the parts manager at the local Chevrolet dealer, and I think that he will get in my corner on this even though I didn't buy the engine from them. I am not going to open anything up in the engine until I have gotten some feed back from Chevrolet on what they want to do. Time for more :beer: :beer: :beer: :( :( :mad:

I had a oil pump on a harley do the screaming squalking screech on a new motor once, the gears were rubbing on the cover, needed a thicker gasket... Just something to keep in mind

Originally posted by dirtrod
I had a oil pump on a harley do the screaming squalking screech on a new motor once, the gears were rubbing on the cover, needed a thicker gasket... Just something to keep in mind

Can't be that because the chebby pump does not have a gasket, and the gears use the cover to keep pressure in the chamber. Besides, when the clutch is depressed, it would not change the tone of the whine if the pump was screwy.