long story short, bought a 90 gt hatch from Virginia 77k on the clock fairly mint. First mustang I've owned let alone ford. I'm just doing a full over on the important things, spark plugs, wires, fluids, red top optima. got an electric fan that'll be in on Monday. but i had a quick few questions to ask. One... rear end fluid, anyone had a problem running synthetic royal purple in the rear? Two, before i even get into the rear, did the GT's come with LSD or is she a one wheeler peeler, just curious so i know before i get into the rear cause ill order the LSD if it doesnt have it.... thanks in advanced for your help. by the way E3 plugs, if anyones been considering them.....they're well worth the money spent.

 

E3 plugs arent worth the space they take up on the counter,

you should be running autolite 25's

the rear diff takes 3.3-3.8 pints on 80w90, just get regular dyno oil, its ALOT better than that royal purple shat. and yes, its a trak-loc differential, and will require friction modifier

 

throw those e3 gimic plugs away....reminds me of the days when the crapid fire and shytfire plugs hit the market claiming 5hp increase in power..lol

 

^^^^ listen to this man, he knows his stuff

also
upgrade to a crane iginition coil while your doing it, and some quality 8mm wires...

 

...Get the FMS 9mm wires...RP rear gear fluid fine!! ...you'll need 2 quarts