Thread: Strange Noise in driveline

If it wasn't doing it before the front diff was replaced I would drive it without the front shaft and see what happens.Don't take this the wrong way but have you got all the oils in?. Pat

Originally Posted by djam1

and last week I put a reco 4 Pinion Military diff in the front.
I now have this odd issue when hot at 100 kmh on float (not overrun or load) I get a noise like a gear chatter.

Anyone have any ideas

It's not related ... but it is

I could give you all sorts of theory's ... and they will be

Is the diff ratios the same? .. tightened all the bolts? ... did you get all the tools that you dropped? ... DID you put oil in the diff? // what sort?


So ... Put the car on blocks ... all 4 wheels off the ground ... start and drive the car in gear // apply driving speed // apply brakes to add forces to make sounds appear or disappear


.... "See" what you can hear



Mike

Thanks guys
Yes I tightened everything (and double checked) the diff ratios were the same I checked that.
I put Penrite 80/90 Diff oil in it and yes its full

Originally Posted by djam1

Thanks guys
Yes I tightened everything (and double checked)

Another thought is ... the diff itself ... does it have excess backlash ... whats it's history? .. as they can be touchy about there setup (C&P position)

Drive it on blocks




So how warm is it today, up there?

Mike

My main concern with the diff is was that it was very tight when I installed it.
I rang the people who built it and they were confident it was ok as the bearings would bed in quickly.
When I say tight it was hard to turn by hand it definately doesnt have too much backlash
It isnt as tight now maybe I just need to give it a few more miles

Originally Posted by djam1

My main concern with the diff is was that it was very tight when I installed it.
I rang the people who built it and they were confident it was ok as the bearings would bed in quickly.
When I say tight it was hard to turn by hand it definately doesnt have too much backlash
It isnt as tight now maybe I just need to give it a few more miles

Sure its not more like a "whining" noise


Diff should have "some resistance" to turn by hand ... but should not require the force of a gorilla to turn

The main setup of a diff is that the Crown teeth are centered to the pinion teeth ... this is where diff noise can mainly come from if "they are new"

A way to check it is to do the following



Put diff in a vice
Smear the crown teeth with a red grease paste
Turn the crown wheel back & forth
This leaves a red grease marking on the face of the "teeth" on the crown & pinion gears

IF the grease mark is HIGH on the teeth = wrong = Noisy
IF the grease mark is LOW on the teeth = wrong = Noisy
IF the grease mark is CENTER or even on the teeth = right setting = no noise

You have to rip it out to check it tho

Mike

The contact pattern was checked before I installed it and it was fine.
It definately isnt a whine but more of a grumble like gear chatter under load and on coast at speed things are fine.
The only other thing I noticed was a slight noise when coasting to a stop

Originally Posted by djam1

The contact pattern was checked before I installed it and it was fine.
It definately isnt a whine but more of a grumble like gear chatter under load and on coast at speed things are fine.
The only other thing I noticed was a slight noise when coasting to a stop

CV's setup OK?

A static drive on blocks will help figure it out