Help with IRS Diff

[Maui coupe]

Hi guys, Since starting to drive the Coupe I've noticed some drive line slack i.e. when letting off the throttle there's a clunking and also when applying throttle-clunk. once its engaged its noise free-ish this car is LOUD! Gordon Levy supposedly re built this Diff cause he charged me for parts and labor, the driveshaft is from Denny's and has no slop. Since I'm replacing my clutch fork and T.O. Bearing (see my other post in FFcars roadsters) should I have this looked at? this is a quick video I did:https://www.youtube.com/watch?v=Usv9IXZCw9Q&feature=youtu.be Thanks!

[chmhasy]

Are you running a Eaton Detroit Truetrac?

[BadAsp427]

FWIW, I have the exact same amount of play in mine and I've also looked at two other builds with the that same diff and they to had the same play. I've found that when just normal driving, you will not even notice that play. When you actually try to hear/feel it, you will. FWIW

[chmhasy]

I just got my car on the road. I do not have carpet or dynamat in my car yet. so I hear everything. I have a 97 Lincoln Diff running 3:55 gears and a Eaton Truetrac. I have the same play. I took the diff apart, my back spacing is in spec. The TrueTrac has the play. I first started off with synthetic / conventional blend oil in the diff. I changed it out to a conventional oil AutoZone STP 85W140 Gear oil. When I let off the gas and the car is coasting / bucking between motor and rear I can hear it. As the car warms up I hear it less and I have to try to buck the car to hear it.

[CraigS]

The TrueTrac I had in my solid axle had that same slop from new. Searching around the web at the time it turned out that is a "characteristic" of TrueTracs. And then they wear themselves out and there are no internal rebuild parts available. I had it for about 5yrs running 15-20 autocrosses per year on Hoosier A7s. When it wore out, I replaced it w/ a Ford stock type unit w/ CF clutch discs. I was SO glad to get rid of the TT.

[chmhasy]

The TrueTrac I had in my solid axle had that same slop from new. Searching around the web at the time it turned out that is a "characteristic" of TrueTracs. And then they wear themselves out and there are no internal rebuild parts available. I had it for about 5yrs running 15-20 autocrosses per year on Hoosier A7s. When it wore out, I replaced it w/ a Ford stock type unit w/ CF clutch discs. I was SO glad to get rid of the TT.

Thank you. I will look to replace it in a few years

[CraigS]

Thank you. I will look to replace it in a few years
I would think yours would last longer than mine did. Those A7s are super grippy so really hard on a lim slip unit.