Pinion slop Detroit locker

[STalon89]

My build is getting close to the finish line and we starting to iron out the little stuff. The truck is hitting a little hard from Park to Reverse, and from what I am reading, its looking like it may be the rear end. Its a brand new 3rd member with a detroit locker. Its a coyote truck with the 6r80, new driveshaft, and freshly rebuilt t case. Anyone have a detroit and can shed some light on this?

 

[Boss Hugg]

In my experience, there can be a lot of slack in properly working Detroit. then you add slack due to gears (I have 5.13 so there's lots of movement back and forth before engagement.) I haven't dealt with hard engagement but I'd be looking for transmission problems. As in, drop it in gear and it spins up too fast until the slack is taken out of the diff. Seems like there is resistance built into my 4r70w to keep that from happening. BUT i'm not a transmission specialist. It's be at least 3 years since I built the last one.

 

[Broncobowsher]

Detroits have a lot of slack in them. Those dog clutches need room to work. So there is a ton of movement between the carrier and the axle shafts. Since there are gears between that and the driveshaft the play is multiplied by the gear ratio. A properly setup Detroit with 4.88 gears was getting close to a quarter turn of the driveshaft between drive and reverse, that is correct. It will be more then a differential that has actual gears in it.

 

[Justafordguy]

I agree, a Detroit will have a lot of slack from forward to reverse. A Grizzly locker is the same, it's totally normal.

 

[Rustytruck]

My Detroit soft locker has about a 1/4 turn on the drive shaft but I don't get a harsh klunk when going into drive normally. When I did have a harsh klunk, it was either too high an Idle speed when in drive over 700 rpm or too high an idle speed when out of drive. Over 1100 rpm. the other time it was a bad u-joint making the klunk when going into drive.
Note: I have a stock 302 and C-4 transmission and 4:11 gearing, nothing to do with a coyote.

 

[DirtDonk]

Mine had more clunk when the driveline angle was slightly off as well. Correcting that did reduce the clunk, but I don't expect it to ever go away completely.
At least not until something else replaces the Detroit.

Paul

 

[STalon89]

I appreciate all of the info.