NOISEY 8 3/4 .Any advice

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highflyer

highflyer

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So after putting in a 323 sg a body rear in the duster last w/e i finally got a chance to drive it...NOISEY is the word..id call the noise typical stick shift noise..not a bearing whine, like an idler bearing but a definate constant whine whether you are on the gas or coasting...the noise goes away if i push the clutch in..Before installing last week.i put a different pinion yoke in it along with a new seal..torqued to factory specs..I browsed fabo forum and found some information on other threads that have questions and and problems exactly like im experiencing..The axles are new dr diff with new green wheel bearings..can i have done the same thing..Torqued and changed the running geometry on that rear ..i have no idea on any of the specs/clearances before i put it under the car..but it sure is noisey..the 8 1/4 i took out was far quieter..HELP..TX..J
 
No,its a 741 case..i didnt figure on anything changing since its set up with shims..but i know VERY little of setting up rears..j
 
My guess is you got the gears back in and not in the same geometry, if you will, and that's why the noise.

Did you take a backlash reading with a dial indicator before you disassembled the gears?
 
No i didnt take out the gears..the whole rear was bolted in..axels were slid in brakes and new plates and a new seal for the pinion..carrier [plug dropout ]was already in i didnt touch it except new seal and retorque a different yoke into it...makes noise under power and coasrting till i put in the clutch..then noise goes away till clutch is released and im under power again..tx..j
 
the rearaxle will still be turning with clutch pushed in, if car is moving.
 
highflyer said:
No i didnt take out the gears..the whole rear was bolted in..axels were slid in brakes and new plates and a new seal for the pinion..carrier [plug dropout ]was already in i didnt touch it except new seal and retorque a different yoke into it...makes noise under power and coasrting till i put in the clutch..then noise goes away till clutch is released and im under power again..tx..j
Click to expand...

OK, did you buy the rear, have it set up by someone? Did you run it before you did the work, and was it quiet?

It sounds like ring and pinion howl to me. If the only thing you did was change the rear and it was quiet before that, then at least you have it narrowed down.
 
No i had not run it before this weekend..it the whole 8 3/4 came with the car and i installed it..i have a receipt for work on it some shop supposedly did.from what i found.wrong nuts holding in axles ..pin seal leaking .when i installed it next morning a puddle was on the floor..so took off pinion yoke removed seal put in new seal and a small u joint yoke..their bill was only 250 and that included new green seals...so couldnt have been too involved..i dont think they got inside..
 
I would pull it all apart and check all the bearings out, pushing the clutch in is a coast condition and taking the load and noise off of a bad bearing. Get a differential kit with new bearings and races that way you know what you have. Also check backlash and gear contact patterns while its apart.
 
blown71duster said:
I would pull it all apart and check all the bearings out, pushing the clutch in is a coast condition and taking the load and noise off of a bad bearing. Get a differential kit with new bearings and races that way you know what you have. Also check backlash and gear contact patterns while its apart.
Click to expand...

Good advice, I would add that you check the backlash you have before you take it apart. .007-.010 is factory recomended.
 
highflyer said:
No i didnt take out the gears..the whole rear was bolted in..axels were slid in brakes and new plates and a new seal for the pinion..carrier [plug dropout ]was already in i didnt touch it except new seal and retorque a different yoke into it...makes noise under power and coasrting till i put in the clutch..then noise goes away till clutch is released and im under power again..tx..j
Click to expand...

That's your problem. If you installed a new yoke, you need to check the backlash and pinion preload.
 
Odd the noise in the diff would go away with the clutch pedal being operated.

You're positive the noise is the diff and not a bearing in the trans possibly
 
no not positive,but i sure dont remember the car making this noise with the 8 1/4 in there..but when i drove it after the switch it sure caught my attention..i was wondering about the trans being the culprit.supposedly this trans was gone thru also..that does make me wonder why the noise pretty much goes away when the clutch is pushed in and it coasts.just a slight pinion whine coasting...but in gaer with gas on it its pretty noisey on and off the gas..thanks j
 
Just like the little dog again..here Wego again..lol..The latest and greatest ,after sliding out a nice 8 1/4 i slid in the 8 and 3/4 SG THAT HAD BEEN GONE THRU..and the noise was pretty bad[see thread].i found another SG 355 and bot it ..Son and i put it in today cause he wanted to paint the brake hubs and we had time to do the rest...QUIET CITY...YEEHAW...the noise is gone..sounds nice..so the fact is it has problems bearings gears or new yoke .when i have time ill look into it maybe attempt my first 8 3/4 build..So for now thanks for all the opinions facts and help on this noisey issue...j
 
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