NV3550 Noise

[greatguy57078]

I took the Bronco into the transmission shop this morning. It is making a rattling noise when the clutch is in, but not every time. I thought it might be the throw-out bearing, which most everyone else agreed with.

The mechanic called me and said that he didn't think that's what it was, at least he didn't think that's what it sounded like.

Any other ideas/opinions what it might be? The trans only has about 16k miles on it. I have not had it off road, but I have barked the tires a few times. %)

 

[blubuckaroo]

It could be the pilot bearing.
There were a number of failures early on with this mod when installers greased the bushing rather than soaking it in oil.
Then there's the caged needle bearing type. I was concerned that those would eventually run dry, and so I used the bushing type.

 

[DirtDonk]

Do you only hear it when it's idling and you manipulate the clutch? Or is it more when you're driving?

What does it sound like?

Paul

 

[Yeller]

Only when clutch is in and not when out it pretty much can only be the throw out bearing or pilot bearing. Virtually anything else will make noise when the clutch is out too

 

[greatguy57078]

I only hear it when working the clutch...mostly at idle or take off. It doesn't make the noise when the clutch is engaged.

 

[blubuckaroo]

I only hear it when working the clutch...mostly at idle or take off. It doesn't make the noise when the clutch is engaged.

Is it rattling when sitting running with the clutch pedal depressed, or when letting the clutch out?

Does it rattle when letting the clutch out with the tranny out of gear?

Maybe it's got driveline, tranny mount, or leaf spring issues?

 

[greatguy57078]

It rattles when the clutch petal is depressed with it in gear. It doesn't do it unless its in gear.

 

[SHX669]

Could it be the "throw out arm " where it attaches to the bell housing - or - where the throw out bearing attaches to the arm with those clips ?

 

[DirtDonk]

Very odd then. If it was a throwout bearing and/or a pilot bearing it would do it almost all the time the clutch pedal was pushed, and be consistent and repeatable most of the time.

The fact that it only does it with the trans in gear and not in neutral is extremely... well, interesting!
My original question was regarding a rear driveline angle issue, which can impart a rattle in the transmission when shifting and the rear pinion tends to angle lower. But if this is a setup with a full 4-link suspension like in your signature, then that should not be the issue either. It would likely make the noise more often when driving around if the driveline angle was off slightly. But not get worse when shifting.
It might change between acceleration and deceleration, but not much I would not think.
And it would have been doing it all along most likely too, since even brand new transmissions are effected by this driveline angle issue.

Have you looked under all of your boots and covers and whatnot lately, to make sure that none of the linkage bits are anywhere near touching body sheet metal?

If you've been driving your 4.6 around very spiritedly and you have big tires and taller gearing, maybe the trans is just feeling stuck in the middle and starting to get looser than normal inside.
Are you using a lubricant that is specifically designed for the NV3550? Did you top it off and then some? Many report their transmissions are quieter with that extra little bit that was left in the bottle when doing the initial fill.

Do you feel anything through the clutch? Or just hear it?
Definitely check shifters, cylinder heads and body parts.

Paul

 

[greatguy57078]

This issue is with my 1968 Bronco. While I did al lot of the work on the chassis back then....the Bronco Connection restored the rest of the truck.

The red Bronco has a 430 HP 351w with the NV3550 manual 5 speed. It only chatters when I have the clutch petal down. We have a cruise through the camp sites every Memorial Day....and with having to hold the clutch in every so often....it was quite annoying to say the least.

I am sick with bad back issues, so I am unable to get up and down. That is why I have it currently at the transmission shop.

 

[greatguy57078]

It drives fine. No shudder or shimmy or nothing. It just chatters/rattles with the clutch in.

 

[DirtDonk]

If you don't get it resolved before the next Camp-Cruise night, use low range in the transmission and just crawl around. I do that all the time when I need to go slow or use the clutch a lot.
Heck, if I have to stop I just turn the key OFF, then hit START when I need to get rolling. Never using the clutch or pulling the trans out of first gear.

Obviously not for every time, but works well under the right circumstances.

Paul

 

[greatguy57078]

Yeah I pretty much put it in first gear and hung back while on parade. WE are heading out to the Black Hills....and I have learned to just shift back and forth between 3-4th gear. Otherwise you're constantly shifting all over as the rolling hills dictate.

 

[blubuckaroo]

It rattles when the clutch petal is depressed with it in gear. It doesn't do it unless its in gear.

I replaced the C4 in mine with a NV3550, so I had to come up with all the manual tranny stuff.
I recall recommendations to measure your bell housing to make sure the pilot was centered properly. Some bell housings were wonky. There was even an example where one was out of alignment and the pilot shaft wore practically through the pilot shaft tube. Evidently, the old three speeds were more forgiving of that misalignment than the NV3550.

 

[greatguy57078]

I got my whole kits from Mantrans I believe out of Minnesota. It came with everything needed to bolt up to my 302. Before I even ran it, I switched over to my 430 HP 351w.

There are a few people that told me that I would regret another manual trans and that as I got older I would wish I had the automatic. Every truck I own is a manual. I only drive an auto when I drive the wife's new Equinox.

 

[blubuckaroo]

Maybe that's why yours is making noise.
These trannys were made to handle a Jeep 4.0.

 

[greatguy57078]

That's what they say. But I can tell you this...I bark the tires every time I drive it. I've left some pretty good black marks...and never had any issues until now.

The transmission guy said the tranny is fine....but I had a Centerforce clutch that had plates in it that he said were causing the issue. I'll know more tomorrow when I go pick it up, but he was sure that it was the clutch that I used....and NOT the NV3550.

 

[DirtDonk]

I agree, but noisy Centerforce clutches were a known thing back in the day too.
It's been so long since we've heard of one rattling though that I totally forgot to ask that old question of what kind of a clutch do you have.

But it sounds like we'll know soon enough. Usually the Centerforce rattle was all the time at idle. But maybe this one is just a little off from wear and tear, and starting to rattle to it's own beat.

Paul

 

[greatguy57078]

It was the "counterweights" rattling against the fingers....or the ring maybe? The bearing was dry and loose also. Man the clutch grabs now! There was light rain when I picked the truck up. I got sideways banging second gear!

 

[DirtDonk]

Great fix! Glad the guy had a good ear and the experience with Centerforce clutches.
The issue does not usually degrade the performance from what I understand, but it's annoying as heck.

What did you put in this time?

Paul