Topic: Knocking noise when in reverse

[Rebeltilldeath3]

Whenever I back up, I get a knocking sound in the drivetrain.  It's not a grinding, but it damn sure is noticable.  The driveshaft has no play.  I figured if my pinion gear came loose again it would be grinding and knocking in any gear/direction.  What else could it be?  I really don't want to tear apart my rear and find nothing, the gear oil doesn't have any metal in it.

[mr4x42u]

did you check the pinion,,with crush sleeves its not uncommon for them to come loose..Do you have a locker in the rear?

[Willy Mammoth]

I have had the pinion hit the carrier before and make this kind of noise. Check your pinion to see if it has any play. You don't have a driveshaft carrier bearing rite?  Have also seen the spider gear pin slide out and hit the pinion too. I would pop it out and look at it too be safe.

[Rebeltilldeath3 [OP]]

did you check the pinion,,with crush sleeves its not uncommon for them to come loose..Do you have a locker in the rear?

No play in the pinion.

I just rebuilt the rear maybe 6 months ago because the pinion was grinding into the carrier, but this is not the same grinding, and it's only in reverse.

[WHITE_TRASH]

Chipped tooth on the reverse idler gear.  Dont get stupid in reverse and it'll live for a long time.

[mr4x42u]

reverse idler gear?

[WHITE_TRASH]

Idler, counter gear whatever.  If it only makes noise in reverse Id bet on reverse gear being chipped.  Its a tiny gear to begin with and its not exactly what Id call strong at all.

[mr4x42u]

so your saying its not white trash beefy,,,BEEFCAKE

[WHITE_TRASH]

  Nope its not WT beefcake.

[Rebeltilldeath3 [OP]]

Chipped tooth on the reverse idler gear. Dont get stupid in reverse and it'll live for a long time.

I haven't been doing anything in reverse other than backing out of parking spaces.  5 grand in 2wd does wonders in the pits.

[Willy Mammoth]

Maybe there is a chip from a forward gear or something stuck in between the teeth of the reverse gear. I have seen this before on a rear end gear and it makes a banging sound when the gears try to pass it. 

I would remove the driveshaft and spin the rear end to see if it has a tight spot. Then put the trans in reverse and get someone to hold the clutch down while you turn the drive shaft and see if it has any tight spots. This will at least give you a clue to what is causing the problem.