Anyone here a Full Floater rear end expert???

Bobalos

Bobalos

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I have a 99 Ram, 2500, 2x4, Cummins, 47RE.

It has the Spicer 70 with 3.5:1 gears & the Limited slip Diff. I think the Posi does not work any more. 

Is there a test that I can do to see if its working & if it is releasing @ the correct TQ?  IIRC there is a test that can be done with a TQ Wrench to see if its functioning correctly, but dont remember where I saw that or the details. 

Im in San Diego, is there a shop here that anyone would suggest that could fix the Posi for me?

thanks

Bob

 
the diff has clutches in it and is rebuildable. more than likely the clutches are shot and need replaced if all you got is one wheel peel. just jack up rear and leave in park and parking brake off try and rotate one wheel by hand.. if you can turn it, the clutches are toast and the other side should go opposite direction. parts are around $600 from what ive found.  (my 02 dodge dually with a dana 80 has a worn out posi as well)

 
I will test it when I get home, but Im pretty sure the test is lying to me............

if its in part & the rear end is off of the ground, one side spins opposite of the other.

if its in N and the rear end is off of the ground, they both spin the same direction. 

the reason why I think its lying is because Ive gotten stuck in the sand & it only digs one hole (just like its an open dif).

 
Bobalos said:
if its in N and the rear end is off of the ground, they both spin the same direction. 
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the reason that is, is because there is still enough pressure to keep both sides spinning same direction as your actually turning the driveshaft by hand. put it in park and you should barely be able to turn a wheel if at all when the posi is good and tight.

 
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I saw my shop manual in the garage and found the test I vaguely remembered.... seems pretty straightforward. 

I might give this a go if I have time this weekend.  I will have to make some kind of gig to hook the wrench too.  

Or....  I might just back the blotch into the street and light it up and see if they both spin....  I know it used to work.....  LOL 

20220413_173202.jpg

 
I still need suggestions on folks to take this too......... 

Anyone used SD Gear & Axle recently???  10 or so years ago, they were pretty well respected. 

 
Why do you want to spend the $$ to fix it? Do you need posi? If you feel you need it, why not put a locker in there if you’re going to spend the money to open it up and pull the carrier?  Even with new posi clutches you may not get drive to both tires in deep sand or mud if the resistance on a tire is greater than the clutches can overcome. With a locker, you will get drive to both tires. A good locker like a Detroit will still allow some difference in wheel speeds when going around turns. Don’t let anyone talk you into welding your spider gears unless you are strictly 100% off road. I’m guessing with a 4x2 you are more like 99% on pavement? 

 
Good points, thanks.  My goal is to fix it and if a locker is a better option I'm open to it.  I just assumed rebuilding the "posi" that's in it would be the easiest way to go.  Like most things this will come down to $/need.  If fixing this is crazy expensive then I will do without.  Who knows how long it's been broken....  

No.... welding the spiders or installing a spool is not an option, this isn't my Chevelle... 

 
A Detroit Locker would probably be fine in a heavy truck like yours. I had one in a CJ7 and it almost never unlocked, which meant I had to "drive" it all the time on the pavement. On the rare occasions when it did unlock, like a really sharp turn taking off from a stop sign or something, it made a pretty loud bang. So not too user friendly, but it made for good four-wheeling. I bought the whole axle assembly complete so maybe it could have had a problem too.

 
I have a Truetrac in the rear end of my F250. I’m pretty happy with it, It works a lot more effectively than the clutch type limited slips, but still has still smooth operation unlike an auto locker. 
 

might be a good option depending on price to rebuild your existing setup. 

 
xtracrispy said:
I have a Truetrac in the rear end of my F250. I’m pretty happy with it, It works a lot more effectively than the clutch type limited slips, but still has still smooth operation unlike an auto locker. 
 

might be a good option depending on price to rebuild your existing setup. 
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I drove a Toyota with front and rear True Trac, that thing would literally climb just about anything.  The locking was seamless!

 
A TrueTrac doesn't really "lock".  Because of it's gear design it doesn't allow a 100%/0% power bias.  Some power will always be applied to both wheels.  The TrueTrac is a common factory "locker" in Jeeps.



 
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