how much noise is to much noise?

[bosworth]

Now that I have the old girl on the road and the exhaust system fixed I'm hearing noise that may be warning of problems to come. First when the car is at idel in neutral with the clutch pedal not pressed there us a noticeable gear or bearing noise, when I press the clutch pedal the noise goes away. Some suggest that this might be the throwout bearing. I would think throwout bearing noise would occur when the pedal is pressed. When cruising at 30 to 45 the car is relatively quiet, gear sounds when the car is accelerating or decelerating with changes in throttle. Things get pretty loud at 55 to 60. If I press the clutch in and let the car coast most of the noise goes away. In summery, how noisey are these cars should I be considering a transmission rebuild. I should have mentioned that I have a 3 speed, no overdrive.

As always, thanks for your great input

Bill

Edited November 3, 2013 by bosworth

[Robert Horne]

My 38 Coupe has a similar noise in neutral since I installed my 5 speed. When it is in gear

or when the pedal is pressed in, no noise, or at any speed so far. So far no problem though.

I suspect it is the throwout bearing. I may pull out the trans this winter for an inspection.....

[Niel Hoback]

  Sounds like the input shaft bearing is noisy. Stepping on the clutch allows the shaft to stop spinning.

[greg g]

Sounds like throwout to me.  Ca you get the car up on a lift and use a stethoscope or piece of broom handle to isolate the noise.  As far aas road nois is concerned, if you are comparing it to one of today's cars, they don't have the sound insulation even half comparable. Is it gear noise? Could it be fan noise, which is coected to egine speed ulike todays stuff where a lot of it is electric and ad constant speed noise.

[Dodgeb4ya]

Sounds like input bearing to me too. But in that case it will be noisy accelerating in 1st and 2nd too and quiet down a bit in 3rd gear.

[TodFitch]

The transmission in my '33 was noisy when idling and the hand brake set. Noise went away when you stepped on the clutch (transmission internals stopped spinning) or when you released the hand brake (apparently some side load on the output shaft). I always figured that it was the output shaft bearing.  The noise disappeared when the transmission was rebuilt with new bearings.

 

Given that the noise is there when you have your foot off the clutch, it seems unlikely it is the throwout bearing as that should be stationary. So its in the transmission. The previous guesses of the input shaft sound good to me, but just wanted to let you know that with that transmission mounted parking brake these old Mopar vehicles can have other ways noise can manifest themselves.

 

As for how far you can safely drive it with that noise, I drove mine with the above condition for about 40K miles.

[Don Coatney]

The noise could be coming from the differential. Have you checked the fluid level?

[bosworth]

Lots to think about. I changed the differential fluid a couple of times. When I first got the car the fluid was low and was very ugly looking. I put in new fluid. I then changed the pinion seal and changed it again. Then again recently I put I Lucas oil. I tried pushing in the clutch and coasting at about 50 MPH and much of the noise went away leading me to think that the rear end is ok, of course the drive line wasn't under any load like that. When everything is hot, I'm sitting still in neutral and I push in the clutching I can briefly hear the sound spinning down leading me to think that the input shaft and whatever else is spinning in neutral is involved. I hope I'm only obsessing!

Bill

[greg g]

Put the car in second gear as it has sychros, having second selected will hold the input shaft from spinning with the clutch engaged.  What sound is it making? Then shift to neutral and let out the clutch, does you target noise come back?  If so then the input bearings may be involved.  If the clutch is dragging, it will have a tendency to turn the shaft in neutral.  You may want to try to adjust your linkage to the throw out fork, making it a bit shorter so that the throw out comes completely away from the clutch plate fingers.  I believe you can see if there is a gap or not by removing the sheet metal dust cover and having a look.

[bosworth]

Greg

When I put it in second, I assume that the clutch is depressed, or should I be moving? I will try it in 2nd and neutral and report back

Bill

[greg g]

Standing still.  Start in neutral, put in the clutch shift, to second for a moment, then back to neutral leaving the clutch in. What if any changes can you hear?

[bosworth]

I decided to try and replace the input shaft bearing in my 3 speed transmission. I ordered a gasket set, small parts kit and input shaft bearing. I really don't want to tear down the whole transmission as it seems to work well, shifts into each gear ok, only makes noise that is consistant with a warn input shaft bearing.

My question, can I just unbolted the input shaft bearing retainer from the front of the transmission and pull out the input shaft? It would appear that the input pinion bear is ingaged with the gear cluster and houses the mainshaft pilot bearing. I ask this because the my manual indicates that when rebuilding the whole transmission, the input shaft and input bearing are the last to be removed. I would like to just replace the input bearing and the mainshaft pilot bearing.

Thanks

Bill

[Dodgeb4ya]

I have done it on regular Mopar passenger cars quite a few times leaving the shaft in the trans as it cannot be removed without first dropping the cluster to the bottom of the case first. .

The cheater way is to remove the retainer. Remove the snap ring and spacer washer. Wedge the bearing and input shaft assembly out enough to get two wide screw drivers behind the bearing outside snap ring. Use a brass hammer and carefully tap the input shaft inward the 1/16 to1/8" that you can. Repeat with shimming.The idea is to carefully wedge the bearing out of the front of the case and at the same time force the input shaft inward and out of the bearing. The input shaft can only be moved in or out of the trans case maybe 3/16" even with the bearing off of it because of the cluster gear teeth block removal of the input shaft. The bearing is a medium tight friction fit on the input shaft and kinda loose in the case and so by wedging the bearing out of the case and at the same time tapping on the end of the input shaft the bearing will walk off the input shaft.

I used to R&R them in about 20 minutes this way once the trans was out on the old Mopars.

Today I use a PosiLok puller to do them.

Bob

Edited November 18, 2013 by Dodgeb4ya

[bosworth]

Bob

Thanks for the input, I think I understand the procedure, sure sounds better than pulling everything apart, obviously I can't change the mainshaft pilot bearings doing it this way but I think the culprit is the drive pinion bearing. Is this a fairly common problem?

Bill

Edited November 18, 2013 by bosworth

[DJ194950]

Bob,

question. on these trans, can the imput shaft come out far enough to allow the needle bearing to fall out of the inside of the imput shaft to the mainshaft. The ones that the main shaft rides on the inner par of the imput shaft?

I remember trying to do this years ago in a forklift and I let the imput shaft come out too far and the needle baerings fell out and down into the trans they went, leading to take a trans completely apart to gather all the needle bearings from the bottom of the case!

Sounds like that cannot happen of these Mopar trans??

Still trying to learn just in case I someday need to do this.

Thanks,

Doug

Edited November 18, 2013 by DJ194950

[Dodgeb4ya]

Doug, The 3 speed car input shaft can not be pulled back far enough to let the needle roller bearings fall out of the end of the input shaft. It will only pull back maybe a 1/4". The needle roller bearings if not worn out will stay in the input shaft even with the shaft out of the trans and in your hand trying to shake then out. There are 14 bearings total in the input shaft. They are held in the shaft by a retaining ring. You could roll the trans over to get them out if you had an issue.

Yes the front bearings do wear out. I have done quite a few of them.

Bob

[DJ194950]

Dodgeb4ya

Thanks for the answer,

Doug

[bosworth]

Success!

This has been a great weekend!  I started by pulling the manifolds and fixing (eliminating) the heat riser which was frozen in the full open position.  Then this afternoon my neighbor and I pulled the transmission (he has a lift) and replaced the input shaft bearing.  We followed Bob's instructions which worked great! Upon examination of the old bearing I became concerned that the noise might be coming from the needle bearings because the input shaft bearing was a bit sloppy, butnot as rough as I expected.  We put everything back together and took her for a drive.  It is now hard to hear any noise at all, even when the transmission is warmed up.  So thanks to the great members of this forum,  another couple of problems are fixed.

Thanks everyone, I am a very happy camper tonight!

Bill

[Dodgeb4ya]

Thats great Bill.. !! No more wondering and worring about all the right things to fx the noise issues and will it ever be a nice and quiet running car again! Hope the weather is good where you are camping Ha Ha

Bob

[greg g]

Good going! Always good to have a interested neighbor to lend a hand and tools and time. Hope your weather gives you occasions to enjoy the fruits of your efforts.  What did you find to use for lubricant when you refilled your box?

[bosworth]

Actually we didn't drain the oil before we pulled the transmission and didn't loose any changing out the bearing. What is in there is half 80-90 gear oil and half Lucas heavy duty oil stabilizer. I think the mix is a bit too thick, I plan to replace it with Lucas 80w90 gear oil, I hope that's good stuff. I notice that I have to be careful shifting into 2nd when the gear case is cold or it will grind into gear. No Problem after it's warmed up.

Next operation, speedometer!

Bill

[greg g]

Make sure your replacement lube is compatable with bronze and brass.  Many of the new ones do not play nice with white metal.

[Don Coatney]

Why oil stabilizer? I would think that the 80/90 weight gear oil is already pretty stable.

[bosworth]

I think your right, the 80w-90 should be all I need, I put the heavy duty Lucas in to see if it would abate the noise and slow down the oil drips. I wasn't getting any drip from the back end of the transmission but from the front of the case, when we pulled it out it was very oily on the front face, so it seems that it must have been leaking from the bearing retainer gasket. Its an interesting system on the front with no seal and a return drain for the oil. I'll look into oil types and see if I can determine which ones are compatible with bronze and brass.

Thanks

Bill

I just spent the past 2 hours reading about gear oils, sure can see their not created equally.

Redline MT-90 GL4 looks good to me, any other recomendations?

Thanks

Bill

Edited December 3, 2013 by bosworth

[greg g]

There is supposed to be a gasket between the trans and the bell housing as it seals the holes in the end of the case that the sliders go into.  W/O the gasket there will always be a leak from the front of the trans.