Noisy Diff?

dotMorse

Club Member
So I have taken my car for it’s first drive longer than 1 mile. After about mile 3 a low grinding started. Turned around. By the time I got home it was fairly loud. Definitely from the rear of the car and no noise when not under load or in neutral rolling.

My assumption is that it’s the diff. Would that be right?

Change the diff oil today but still a grinding noise (straight away now but only while under load)

What are the options for a diff rebuild or for a replacement. Mine is a US 240z 4 speed so guessing it’s the 3.36 ratio.

I guess I might need to look into a new diff. Any advice?
 

ALN

Club Member
So I have taken my car for it’s first drive longer than 1 mile. After about mile 3 a low grinding started. Turned around. By the time I got home it was fairly loud. Definitely from the rear of the car and no noise when not under load or in neutral rolling.

My assumption is that it’s the diff. Would that be right?

Change the diff oil today but still a grinding noise (straight away now but only while under load)

What are the options for a diff rebuild or for a replacement. Mine is a US 240z 4 speed so guessing it’s the 3.36 ratio.

I guess I might need to look into a new diff. Any advice?
Could also be the u-joints on the driveshafts... Mines started that way and only made noise under load, no noise whilst "free-wheeling"...
 

dotMorse

Club Member
So replaced the diff with one from @Mr Tenno and now no noise.

Success

BUT now it doesn’t like to rev under load. Go over 2k revs and it struggles.

Could this diff be a higher ratio? Is there a solution to this?
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
That might be the common problem of blocked fuel filter? The diff ratio wouldn't cause anything that severe.
 

dotMorse

Club Member
Thanks rob. Will take a look at the fuel filter tonight. That would make a lot of sense.

In other news I also have some coolant in the inside of the bonnet. Looks like it could be out the breather. No overheating while driving though. Temps all read fine. Again what could be the cause of this?

Nothing like getting the car built. Then the real work starts.
 

dotMorse

Club Member
I have just put in a new mechanical fuel pump as the old thought the engine could survive on a tumble of fuel every couple of hours.

Hopefully the new one has not gone. Going to pull the fuel filter tonight and see what it looks like.
 

Farmer42

Club Member
The coolant could be a sticky thermostat. If it gets up to temperature and doesnt open, the pressure builds up and releases through the cap and overflow pipe. It then settles and is fine. You will see your temp gauge go right up then fall back when it opens but if it releases coolant before that happens, you might want to think about getting a thermostat with a lower opening temp. I changed from a 86 degree to an 82 (poss 84) degree and it cured the problem.
 
Top