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Heavy weight diff oil
jimgiblett - 10/10/11 at 10:25 AM

My latest project is my 300hp 67 Alfa. All is going well but I want to quieten down the diff. The diff currently is filled with Millers CRX80w90 BM. Are there any downsides with replacing this with CRX LS 75w-140 NT. I assume the 140 will be higher viscosity.

What do you guys (oil experts) think. The diff is an uprated 2ltr version with plate LSD.

cheers

Jim


minitici - 10/10/11 at 06:08 PM

Stick some sawdust in it and sell it quick


NS Dev - 10/10/11 at 09:49 PM

Unfortunately noise from a diff is never a good thing! Oil viscosity won't make a huge difference at the sort of loadings that hypoid gears see. No harmtrying the oil though


Oddified - 11/10/11 at 07:54 AM

Try putting some 'Lucas Heavy Duty Oil Stabalizer' in there. It does make a difference in diff's, and it's also pretty good in straight cut boxes making them far quieter

Use about 50/50 with the normal gear oil.

Ian


adithorp - 11/10/11 at 08:38 AM

Not really my field but wouldn't the higher viscoity effect the LSD?

I'd try some "Forte Diff and Gear treatment". I've had good results with it. Everything from quietening noisey diffs, to making knackered gearboxes last untill customers could afford to replace the car (12mths in a mates Fiat and still going when he traded it).
If you can't get any locally (not always easy to get outside the trade) let me know and I'll post you some.


jimgiblett - 11/10/11 at 04:57 PM

quote:
Originally posted by adithorp
Not really my field but wouldn't the higher viscoity effect the LSD?

I'd try some "Forte Diff and Gear treatment". I've had good results with it. Everything from quietening noisey diffs, to making knackered gearboxes last untill customers could afford to replace the car (12mths in a mates Fiat and still going when he traded it).
If you can't get any locally (not always easy to get outside the trade) let me know and I'll post you some.


I am going to have a good look at it at the weekend. Someone has suggested the noise may be one of the pinion bearings. I checked for play but nothing noticable, but as there are two front pinion bearings it could be just one that is collapsing.

Thanks for the offer though I may still take you up on it.

Cheers

Jim