14 Bolt Detroit—Blown?

[Hosalabad]

I was on my way to South Carolina and I made a right turn in a parking lot. There was a hellacious bang at the mid point of the turn. The Blazer kept moving fine, so I parked and looked around for something explodey. I saw no signs of damage and finished my ride to Charleston and drove it around the beach for a week. On the way home the weeping seal became a leaking seal. I was down about two quarts. Made a right coming off an off ramp for gas and two more bangs, truck still driving fine. I looked under and saw the seal and limped to an Oreillys for oil. Topped it off and made it home with no drama.

Then the question is, what is the banging noise. It’s from behind me so the only culprit is the rear end.

Today I jacked up the passenger side and notice that I could easily turn the wheel in reverse. Forwards locks immediately.

I’m stuck on the noise and the turning backwards.

The banging noise makes me think something is binding or something broke and pieces are swimming around until the locker tries to allow differential action in a turn and then it binds and snaps loose making the noise.



Any ideas or trouble shooting suggestions ? No obvious chunks came out with the oil when I took off the cover.

View attachment IMG_0327.mov

 

[Hosalabad]

Video is right side being turned forwards then back.

Left does the same but in reverse. It unlocks going forward and locks in reverse.

 

[obijuank5]

That is the working nature of the Detroit. By your description I believe that to be functional.
Welcome to the thunder dome.

Several, probably many years ago now, they introduced the SL part numbers for soft locker. If yours is a cucv or old unit, it’s gonna bang like that.
It’s always funniest when I picked up my kids from preschool with a loud bang and chirping the tires in the crew cab. Coolest dad ever!

 

[Hosalabad]

That is the working nature of the Detroit. By your description I believe that to be functional.
Welcome to the thunder dome.

Several, probably many years ago now, they introduced the SL part numbers for soft locker. If yours is a cucv or old unit, it’s gonna bang like that.
It’s always funniest when I picked up my kids from preschool with a loud bang and chirping the tires in the crew cab. Coolest dad ever!

That’s wild. You mean a vehicle shuddering bang?

I’ve had this axle on the road for 10-15k miles and it’s never done it until this trip.

 

[obijuank5]

Yes the kind that makes you get out and see if your driveshaft is still attached. Yes the kind you are describing. Very embarrassing lmao

 

[centexk5]

I’ve got the soft lock version and you hear nothing going around turns but there is no doubt it’s locked.

 

[cheavyk10]

My grizzly locker does it too, once in a while.

 

[HankScorpio]

My Detroit goes bang. Frightening loud bang, it's just what they do sometimes. It also chirps the tires everywhere.

 

[tRustyK5]

It's worse with a manual trans rig...but completely normal. Shit just gets a bit bound up now and then, and the bang is the release.

 

[Hosalabad]

Thanks for the reassurance. Now I can focus on the seal and then track down wherever it is that I'm losing brake juice.

 

[tarussell]

Just adding another vote of confidence on that being the nature of the non S/L Detroits.

First time mine did it I was in a middle of a turn in a big intersection while shifting into third gear and “BANG” - as I was trying to get my drawers unsucked outta my crack I pushed the clutch in and coasted off the road and was expecting to find the rear shaft gone!
But all was well - I even took it apart when I got back home to inspect everything.

It seems to happen mostly upon an unloaded or reapplied power situation - driving with a D/L in several trucks it’s only done the big-bang about a dozen times so it’s not a constant thing.

 

[JT88K5]

I had a Detroit locker. When it unlocked and I had a passenger with me it was always funny to see the look on their face. Surprised there were never any brown spots on the seat afterwards. I’m pretty sure that’s what hammered the CV joint on the rear drive shaft after -10k miles.