Clutch Chatter

[Gearhead]

That's a real interesting idea.

I don't often consider that posters aren't able to articulate what they're actually experiencing.

I took it to mean he never used the granny gear in his NP-435 under normal conditions.

With many of these gearboxes you could literally sidestep the clutch at idle in first and the truck would lurch to a walking pace.

Not much chance for the clutch to shudder with deep ratios like that.

True, but my experience has been if it is the clutch chattering, under normal clutch application it chatters in all to various degrees. Also, to replace a clutch and still have the same problem is very unusual. The only remaining possibility I see is a excessively worn bearing retainer causing the throw out bearing to bind. That should be very noticeable.

[ArdWrknTrk]

True, but my experience has been if it is the clutch chattering, under normal clutch application it chatters in all to various degrees. Also, to replace a clutch and still have the same problem is very unusual. The only remaining possibility I see is a excessively worn bearing retainer causing the throw out bearing to bind. That should be very noticeable.

You have more experience -with more clutches- than me.

Can you tell me what you mean by bearing retainer?

The release fork??

The input sleeve??

I usually apply the smallest bit of Moly-60 paste to these surfaces.

Graphite exhaust sealant works too.

[Gearhead]

You have more experience -with more clutches- than me.

Can you tell me what you mean by bearing retainer?

The release fork??

The input sleeve??

I usually apply the smallest bit of Moly-60 paste to these surfaces.

Graphite exhaust sealant works too.

It's what the throw out bearing rides on, your probably thinking input sleeve. I've just used molly bearing grease to lube the throw out bearing. I've read that graphite can act as sand paper below zero farenheit. If the sleeve is excessively worn it could cause the bearing to bind during release of the clutch.

[ArdWrknTrk]

It's what the throw out bearing rides on, your probably thinking input sleeve. I've just used molly bearing grease to lube the throw out bearing. I've read that graphite can act as sand paper below zero farenheit. If the sleeve is excessively worn it could cause the bearing to bind during release of the clutch.

Yes, I'm thinking input sleeve.

The Honda Moly-60 paste is meant for splines (extreme pressure and temps, little or no rotation)

It works great here without any chance of contaminating the clutch.

[Les Kerf]

I am on my third Bullnose now and they ALL have/had the clutch chatter issue. My 74 F-350 doesn't do it, nor did my 73 F-250 or the 78 F-150.

I had an 81 F-150 with 300-6/T-18 and 2.75 gears that was just awful, my current 85 F-150 with 300-6/NP435 and 3.08 gears is somewhat better but if you get careless it will give you a good shaking as if to let you know who is really the boss.

I read on another forum that the firewall mounting position is weak and can be re-enforced with a thicker metal plate but I have never tried it.

This is definitely my biggest gripe with the Bullnose series even though I dearly love most things about them.

 

[ArdWrknTrk]

I am on my third Bullnose now and they ALL have/had the clutch chatter issue. My 74 F-350 doesn't do it, nor did my 73 F-250 or the 78 F-150.

I had an 81 F-150 with 300-6/T-18 and 2.75 gears that was just awful, my current 85 F-150 with 300-6/NP435 and 3.08 gears is somewhat better but if you get careless it will give you a good shaking as if to let you know who is really the boss.

I read on another forum that the firewall mounting position is weak and can be re-enforced with a thicker metal plate but I have never tried it.

This is definitely my biggest gripe with the Bullnose series even though I dearly love most things about them.

Your 81 doesn't have a hydraulic clutch, so there's no real difference between it and your '70's trucks in that regard.

If you're not getting smooth engagement I'd first look at friction contamination or a heat spotted flywheel.

There's no reason to have to put up with a shuddering clutch.

[red1980F150]

If the sleeve is excessively worn it could cause the bearing to bind during release of the clutch.

I had this happen on my old mustang. We replaced the T/O bearing and I don't remember how long it took to ruin the new bearing... but it was months, not years.