Rear end noise when turning

[bigblockwilly]

Hay guys having some trouble with rear diff in my Bel air. Originally a 3.36 open that I sacrificed to the horsepower gods long ago. After going through another open diff I wised up and got a posi unit. Used but in good shape clutches looked good took it apart cleaned and lubed everything and it was fine... for a while. Now whenever I turn (mostly seems like just when I'm under power) it makes a horrendous clunking noise. My assumption is that it is not disengaging when I turn. I just did a Google search and found this "one thing to watch for, Posi rears use axles 1/8" shorter than open rears, otherwise they all interchange."... any truth to this? Thanks in advance.
Willybang

 

[yellow wagon]

did you remember to add positraction additive when you filled the rear with oil? :?

 

[bigblockwilly]

Yes I did My first thought that it was just some chatter so I took it out did some figure 8's and did not help it sounds more like there is something binding up and releasing it makes me cringe whenever I take a turn and hear it.

 

[MRHP]

Put in more additive. Might take 3. Pretty common concern. Been there myself.

 

[1958 delivery]

Yup, more posi fluid (whale sperm?) I had a fresh one that snapped and clunked like the rear end was about to fall out, more posi fluid cured it, along with some additional figure 8's.

 

[bigblockwilly]

Thanks guys, I will put some more posi fluid in her tomorrow and do some figure 8's and see what that does. Hopefully this is an easy fix i really don't want to pull the diff out for the umpteenth time. Thanks for the advice
Willy

 

[Phil Reed]

(whale sperm?)

Close but not quite!!!! It is made from blubber from a................................ Sperm whale!!!! But I loved your anwer better than mine!!!!!

 

[Iowa 409 Guy]

Who would you ever find to harvest that "whale sperm"------------maybe a female whale>>>>>>>>>>>>>

 

[4onthefloor]

I think GM discontinued the whale/fish oil stuff . That was the best posi additive.

 

[dq409]

If whale sperm smell anything like Posi additive it`s no wonder the whale population is in decline!!

No female whale in her right mind would go near that stuff!!!

 

[bigblockwilly]

Hahaha Whale sperm huh? Well I put some additive in did about 20 minuets of figure 8's and it did not help at all. When I put it in I dipped my finger in the gear oil level was good, but there was an awful lot of metallic in the fluid. Thanks for the help
Willy

 

[jim_ss409]

All this talk about whale sperm reminds me of a saying I once read...

"Whale oil beef hooked"

You have to say it out loud in your best Irish accent.bang

 

[65FO-OH-9]

Who would you ever find to harvest that "whale sperm"------------maybe a female whale>>>>>>>>>>>>>

Rosie O' Donnell. :argue:

 

[1958 delivery]

Rosie O' Donnell. :argue:

Nah, she would eat it all up.

 

[MRHP]

Did you stack the steels and frictions in the right order?

 

[bigblockwilly]

Yes I did. I will probably pull the diff out tomorrow and inspect it just to make sure nothing is wrong internally.

 

[jdk971]

Rosie O' Donnell. :argue:

maybe barney frank? sorry i had to jim

 

[Don Jacks]

With a lot of metal in the oil,carrier brgs?:?

 

[dq409]

I just did a Google search and found this "one thing to watch for, Posi rears use axles 1/8" shorter than open rears, otherwise they all interchange."... any truth to this? Thanks in advance.
Willybang

When I had my new gears installed and ordered my Dutchman axles my rear end guy whet there and measured the new axles so he could check to make sure that they were not too long and would not cause problem.
Even though they were built to my stock axles length he wanted those measurement to check against the axle housing length to make sure.
You can never measure too much

 

[oldskydog]

Hay guys having some trouble with rear diff in my Bel air. Originally a 3.36 open that I sacrificed to the horsepower gods long ago. After going through another open diff I wised up and got a posi unit. Used but in good shape clutches looked good took it apart cleaned and lubed everything and it was fine... for a while. Now whenever I turn (mostly seems like just when I'm under power) it makes a horrendous clunking noise. My assumption is that it is not disengaging when I turn. I just did a Google search and found this "one thing to watch for, Posi rears use axles 1/8" shorter than open rears, otherwise they all interchange."... any truth to this? Thanks in advance.
Willybang

Here's the chart and there is further discussion here:
http://www.348-409.com/forum/showthread.php?t=9868