Hey all,

I am a bit confused as to what the go is with my diff. I have a AU series 1 Fairmont Ghia 6 cyl VCT. I have read somewhere that the only way to get an LSD on one of these cars is with the Tickford rims and suspensoin package or something, my car has neither of these, however it is fitted with an LSD, Ford confirmed that my car was fitted with an LSD from factory when I gave them my VIN. My question is is this diff common or rare or does anyone know anything about it?

The LSD doesnt work as well as I would like so I decided to change the oil, the first place I went to had no clue, they just said to use a 90 weight non LSD oil coz they couldnt find the spec for my car. Repco however was more helpful. The guy found my diff and directed me to the right oil for it, which was over $30 for 1L, so I just ended up buying 80w-90 LSD oil and I put that in. Is that going to be alright? It does have a tag saying "use high performance oil only"

Also, whats the g.o. with rebuilding these diffs, to get it to stop "singling out" can I just shim it up or will that break it? I have heard there are problems with these diffs so thats a worry. Any info anyone has on these diffs is appreciated, thanks.

I have had no probs in using Castrol LSX90 in an AU IRS LSD diff.
I run Penrite Limslip 140 in my ED LSD.....no probs.

 

 

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Thanks for the reply mate.

Im thinking that I need to change the oil to the type that I have been told because its starting to wine around 80km/h. It didn't do that before the oil change.

To start with, you need 2 litres of Redline 80W140 GL-5 Gear Oil - best stuff going. It is formulated especially for LSD. A lot of experienced Ford mechanics use it routinely as it fixes most noisy diffs instantly. It's recommended for racing, so it can handle a lot of abuse. Remember to shake the bottle well before pouring in - it has a lot of moly in it, which tends to settle out. I use it in both my EF and AU2 LSDs. The factory recommendation is 75W90 - but the 80W140 is better for any diff already run in, as it helps tighten up the limited slip and reduces noise.

If that doesn't fix it, there is a know problem with the AU IRS LSDs having noisy diffs - mine had it. A friendly Ford mechanic had seen it many times, and fixed it for cheap at home. Apparently, the diff was set up too tight from the factory, and there were high spots on the cones which tended to get hot. The high spots are easily visible, as they are blue from the heat. He removed them with emery cloth, put the diff back together with Redline oil, and it's been perfect. No noise, no chatter, and it's tight as!