would anybody happen to know how to tell if a rear end is starting to go out? i have a pretty good idea mine is but i want to be dead sure.

 

how much play do you have between the ring and pinion when put into gear? is it making noise?

 

You'll have to pull the diff cover, measure backlash, remove the carrier and ring gear, inspect the bearings and races, measure pinion bearing preload, inspect teeth wear on the ring gear and the pinion gear.

 

Can you tell us what axle. Good info from 78, just need to know if you understand the terms, I know I wouldn't at 17.

 

I should go more in depth with what each one is and how to go about it. Maybe even write up a short tech article with pics.......

 

You would know it. IT will make lots of noise You can squeeze a B body 8 3/4 in your Aspen

 

It kinda sounds like like my 440 is misfiring but it runs just fine and its rebuilt with around 500 miles on it. It feels like the car jumps back and forth a little at speeds over 30. I think its a 7.25 which I know wont live long. i have and 8.75 rear end I just dont have a third member for it yet. It doesnt make a lot of noise, but Im pretty sure thats where the noise is coming from. I havent measured anything so im not sure if end play or anything else is ok or not. when we (my grandfather and I) took the cover off, everything looked just fine. turned smooth and didnt make any noise. also, would anyone happen to know where I could get a fairly cheap 3rd member for an 8.75? doesnt have to be anything special. an open carrier would be just fine for now. I just dont want my diff to bite the dust and me be stranded somewhere. And please go into as much detail as you want. Id like to learn as much as i can. thanks for the help guys

 

I know there are three difference center sections for the 8.75 rear axles. One of them isn't that desirable (I believe it has to do with bearing size) and can probably be had for less than the other two. I don't recall which on that is though.

I'll see about doing a small write up on the measurements. Will most likely be on a D60 rear axle since I've got one kicking around but the work and what needs to be done is all the same.

 

quick search on ebay showed these:

http://www.ebay.com/itm/8-3-4-3-23-R...60a3f0&vxp=mtr

http://www.ebay.com/itm/8-3-4-REAREN...966468&vxp=mtr

http://www.ebay.com/itm/8-3-4-REAREN...055e72&vxp=mtr

Now I know that the different body cars had different width axles but I don't think the center sections changed. Someone will correct me if I am wrong.

 

that may be a carb issue also.... Chime in here you carb masters.
What kind of carb?
you may have a surging or hesitation caused by the power valve needing to be tuned...+ -.
she may be running lean. just off idle .
Just some ideas here .

 

the carb is an edelbrock 750. nothin special. and by lookin at my exhaust pipes, if anything Its running a little rich. But im no expert.

 

8 3/4 types series of numbers on drivers side Last three #s are what people refer to..
741 center least desirable has small pinion bearing still will take some punishment
742 very strong properly built will take an extreme amount of abuse pinion bearing pre load adjusted with shims
489 also very strong only difference is it uses a crush sleeve to set pinion bearing pre load

Those Ebay listings are junk I wouldn't buy any of them

 

Regarding that surge. Try the same speed at a lower gear, it will be cruising at a higher RPM and this can give you further info. If you have a vacum gauge run it through both senarios and record the readings. this could help diagnose your spring. It could be too weak and opening too soon or fluctuating giving the surge condition.
Do you know what your mechanical advance is and at what RPM the total is at?

 

I do have a vacum gauge so i will check that out for sure, and as for timing advance i will have to look.

 

So i checked vacum doin around 40-45 in 3rd and 2nd gear. 3rd gear at 2500rpm had about 10 inches of vacum and 2nd gear at 3500rpm had about 15 inches of vacum

 

At what in lbs, vacuum did the motor start hesitating / surging did you notice?
was it less at higher rpm / vacuum

 

surging ive noticed has gotten worse. it hesitates around 1500-2000rpm and if im in second running 3500rpm (cause thats when that cam starts to make power) and push that pedal through the floor, itl hesitate then take off. and im certain my timing needs to be adjusted on top of all that. idles just fine but backfires after i redline at 5000rpm. and vacuum varies. ive had it be at 10 inches (im not sure about pounds) at 2000 and 5 inches at 3000. but thats not constant.

 

I think it's time for "back to basics". Initial and total timing at what RPM for total is critical. Do this with vacum advance disconnected and plugged. If you don't know how You Tube has tons of info on this.

 

After setting your timing...what type of dizzy are you running?
we still don't know what type of carb you have
sounds like you need a power valve adjustment and check the accl pump and even the jets may need tuning
set the timing first though.

 

where exactly are these casting numbers found?

 

Driver's side bottom of "snout" between U-joint and axle tube.

http://www.wichitamopar.com/wp-conte...NFORMATION.pdf

I would suggest starting a new Title for your engine problem as the title of this thread may through some people off who would otherwise help advise on engine and not on rear axle. Be sure to give as much detail as possible i.e. rear axle ratio and torque convertor stall rpm if possible.

 

thats what im going to do. im positive my rear end is fine for the time being