Good time to change gear oil?

[mustang1]

just driving home today and thinking about how my vert has 150,xxx miles on it and i dont think my gear oil has been changed once judging by all the gunk on the housing bolts. So how often should i change my gear oil? I'm almost positive i have stock gears btw with an AODE so its never been great off the line anyway. thanks.

 

[Lee12609]

i'd change it for piece of mind, my cars usually get it every 25k miles, and i ONLY use royal purple, i also choose not to use a friction modifier since royal purple has the additives needed for our trac-loc diffs.

 

[pp_puncher]

25k seems excessively early. Considering Ford's interval is 150,000 mi.

 

[Lee12609]

25k seems excessively early. Considering Ford's interval is 150,000 mi.

ford didnt intend for me to drag race my car either.......

 

[wytstang]

And mustangs are for just cruising? Of course we beat on them and of course they know that. Earliest I would do is 75k, remember Ford diff oil is made from whale fat so it is not your average oil. Stinks to high heaven thats for sure.

 

[mustang1]

good to know im almost right on time and i will for sure be using RP since ive heard nothing but great things about it. Anything else i should do while im back there besides the obvious of getting 3.73 or 4.10's. Thanks again

 

[Lee12609]

And mustangs are for just cruising? Of course we beat on them and of course they know that. Earliest I would do is 75k, remember Ford diff oil is made from whale fat so it is not your average oil. Stinks to high heaven thats for sure.

Ford oil??? ha, this car has over 200k miles on it. i used mobil 1 extended performance and still change at 3000 miles, so yes, overkill is my middle name. i also change my trans filter/fluid every 25k with mercon V and motorcraft filter aswell........

 

[Win]

I use Valvoline 75w90 full syn with Friction Modifier since i had my rear end rebuilt with Carbon disc for the trac loc and my 3.73 installed.

 

[pp_puncher]

I use Valvoline 75w90 full syn with Friction Modifier since i had my rear end rebuilt with Carbon disc for the trac loc and my 3.73 installed.

I thought it already had friction modifier in it?

 

[Win]

I use Valvoline 75w90 full syn with Friction Modifier since i had my rear end rebuilt with Carbon disc for the trac loc and my 3.73 installed.

I thought it already had friction modifier in it?

Don't see it directly on there site.

It was recommended by a local guy that rebuilds 8.8's and also drags his 03 Cobra that has a SRA in it.

 

[Lee12609]

Its not going to hurt anything to run the modifier even if its in the oil already. All its basically used for is clutchpack noise anyways.

Not sure if the Kevlar clutches have different requirements its possible.

 

[switch96]

No wonder my gear oil smelled so terrible lol.

 

[gnx547]

How many quarts does the rear end take?

 

[pp_puncher]

about 2-3/4 qts.

 

[gnx547]

Can I use regular Valvoline 75w-90? I have heard if you don't use the modifier with the gear lube, the rear end will make noise, not sure if that is true.

 

[cam302]

hey guys new here but i work at a lube shop and we use manufacture intervals on every thing the rear diff is due every 12 to 15k with gl5 and an additive or you can use a synthetic and thats good for every 25k to 30k we do not recommend this. for the manual trans in are cars its also due at the same time but if you have a auto you should flush it first at 50k and then every 30 after that. i change my motor oil every 2500 with mobile 1 10w30 full synthetic and my t5 every 15k with gl5 and the additive and same with my rear diff. just because the oil looks good dont mean its doing its job all oils brake down.