RebelExtrm02

iTrader: (3)

My rear end (stock 7.5" 10 bolt with 121k on it) has made clunking sounds when resuming from a coast or when the car bucks (big cam) at low rpms since I bought it (110k). I know it's the rear end because the suspension is all new and I've had the the rest of drive train out and refreshed and it all checked out.

When I replaced my pinion seal i noticed I could spin the pinion yoke about 10 or so degrees before it would engage the axles. There is no side to side play in the axles and if you push on the tires laterally and there is no noise or play so I think the axle bearings are still decent. The rear end is dead silent otherwise, with no whining at any speed.

When I changed the fluid recently everything was still in one piece in the pumpkin. I didn't check any gear patterns or anything because I don't know to do all that yet. I'm still researching/learning about rear ends.

Does this sound like an issue that could be fixed by re-setting up the rear end or am I looking at a complete rebuild? From my research it sounds like it could be excessive backlash. Maybe I should just live with it since the rearend hasn't blown up yet haha.

Won-Ton

Manual or Auto? Does it clunk when it goes into reverse and then again into first? Is the clunk while coasting a one time immediate result of letting off the gas?

Is there play in the driveshaft? After driving around for 30 minutes are the u-joints hot to the touch? I doubt its the u-joints, but easier and cheaper things first.

RebelExtrm02

iTrader: (3)

Sorry about that. It's a manual t56. I haven't made note of a sound going from reverse to forward. I'll pay attension when I pick the car up from the inspection shop today. The clunk doesn't happen when you let off. It happens when power is reapplied abruptly or when the engine is surging at low rpms from the cam. If I ease into the gas it won't make the sound. The transmission was overhauled few years ago and it has a new slave, shimmed clutch assembly, and flywheel. No fluid leaks at all and no play where the driveshaft inserts into the transmission. The ujoints appear to be fine on the driveshaft too. I inspected them when the driveshaft was out. Everything felt snug and smooth when articulated or rotated.

Won-Ton

Ohhhh gotcha, that is an interesting one. Typically my experience excessive backlash you can feel it as a single clunk especially from stop and/or like backing out a parking spot. Some play at the yoke is pretty typical, especially in a "higher" mileage gear set.

What you are describing almost sounds like the ring gear bolts are loose which I have seen on 8.8s/9. Or play in the carrier bearings.

RebelExtrm02

iTrader: (3)

I played around with it today and the reason I don't notice it when accelerating or reversing is because of how I ease into my clutch when I drive normally. It gradually takes up the slack and you don't notice or hear anything. However if I reverse, throw it in neutral, stop, then let the clutch out quickly in 1st you can hear a quick clank from the rear of the car as the slack is taken up. I also have a tendency to throw it in neutral when slowing down for stops so that's why I don't hear it on deceleration. If I leave it in gear and juke the gas pedal a few times I can make the sound happen. Pretty much any time there is slack between the engine's rotation and the rear and it's taken up quickly is when you hear the sound.

Won-Ton

Assuming the R&P are still good, resetting up the gears with used gears is just as much if not more work than doing new gears.

Typically I do not like waiting until it breaks on my stuff since it usually takes out other more expensive components, however I am not familiar with what will give out on the 10 bolts first.

01ssreda4

iTrader: (96)

Normal. What type of suspension do you have? Mine got worse when I added aftermarket suspension and added a cam. Considering I build rear ends on a regular basis I know for a fact nothing is wrong inside mine. The fix? Dont lug your car down that low. Mine was a tune issue since im auto but would allow me at light throttle under certain conditions to get down to 1k rpms and cause some light bucking which you can hear beating on the ring and pinion gears. I adjusted the tune to prevent that condition and now it doesnt happen.

RebelExtrm02

iTrader: (3)

Koni Sports with BMR lowering springs and tubular control arms. Fresh bushings everywhere. Come to think of it I started noticing it the year I upgraded the suspension from stock parts. I have a new grabbier clutch too. Im also due to have the car retuned in a couple weeks and will hopefully improve the low rpm surging. Maybe Ill just open up the rear again and double check everything is in one piece and let it ride, especially if the tune helps.

From what ive researched most cars bust the ring gear or axles. The 7.5" 10-bolt R&P are undersized and the housing flexes under power.

Won-Ton

Maybe it was doing this all along, but couldn't tell with the old worn out bushings? Yeah I am shocked they ever used them, and to think I was worried about the Dana 44 hahaha

RebelExtrm02

iTrader: (3)

Finally had my car tuned by a competent tuner. It no longer surges and bucks. It doesn't hang between shifts. Gear transitions are smooth as a new car. I never hear my rearend now. Thanks!

01ssreda4

iTrader: (96)

I figured thats what it was.