How's this! Just had to have Diff reco!

[Francis]

just had to have the diff in my late model ford reco'ed and it's just hit the 50,000kms! They guy was telling me that the company that bought out the diff maker had changed a few years ago and now they are seeing noisy diff's anytime after 20,000 kms.

Anyway the interesting think they told me is that they have had a lot of trouble with using the Castrol Synthetic 85/140 LSD. He said even though the hand book tells you to use it, they have better results with the High performance Mineral LSD oil. Apparently the Synthetic oil gets to thin when hot and starts to ware the diff out. So they only use the mineral oil now and don't have any issues. And this is from one of the most respected diff places in the country!

 

[oilboy123]

Maybe that syn lube was not up to snuff.......


I think a quality syn will be better than a quality dino lube in a marginal application.
A syn will hold up better in a hot application as opposed to a dino lube.


I don't care how respected they are! Me don't agree........

 

[UncleRunkle]

late model ford what?

 

[Pablo]

Quote:
.....better results with the High performance Mineral LSD oil. Apparently the Synthetic oil gets to thin when hot and starts to ware the diff out.


Some conventional petro based gear oils do fine…..but I’m not buying this.

Are they saying the synthetic lube listed falls out of specification when hot or are they saying in general synthetic gear oil is “too thin when hot…..yada yada …..”? Contrary to popular belief synthetic gear oils have to meet the same high temp requirements as conventional oils, which includes viscosity, etc and in fact have less tendency to thin out at high temps….

Interesting, none-the-less!

 

[Francis]

I think the point the guy was getting at was that while Syn Diff oil technicaly is better they seem to see less problems or issues with high quality performance mineral oils in the diff's they rebuild.

I thought I would check this so I rang another diff shop in another part of the state and he said the same thing. He said while on paper it made all the claims to be better they notice less issues using mineral oils. He said the biggest plus for mineral oils is they tend to help with LSD chatter better then synthetics and all the diffs the repair,. rebuild or supply leave with high performance mineral oil and never come back.

 

[unDummy]

I don't agree.

Typical rebuilds with upgraded parts will last longer then the [censored] rolling out of the assembly lines these days. So, what fluid they used for the rebuild is meaningless if the components are better.

What this shows is that the 'required' synthetic isn't a big enough bandaid for poorly manufactured or cheaply sourced OE parts. Yep, fluid visc, additive packages, and fluid types are being used to make up for and allow supplier 'cheapness'.

LSD noise is easily solved by using an appropriate LSD additive.