Ok boys and girls, I think I've got a problem building up here. I'm pretty sure I've narrowed the sound down to comming from the back end. I running an automatic 4l30e tranny in my 96' Rodeo and lately I've noticed an increasing grinding/ringing sound coming from the rear. It occurs whether I'm in neutral, reverse or forward and most obviously when I'm accelerating or decelerating against the engine. In otherwords, it's most noticeable when I'm not coasting at a constant speed but still there barely noticeable when I am. Basically the sound is more prevelent when there is pressure on the drive train in one way or the other, and the sound gets progressively higher pitched the faster I am going, not engine rpm dependent. I'm pretty sure that it's got to be something in the diff at this point as I took it to a local lube place as soon as I heard it and had the fluid level checked. Don't kill me for this one guys, I know I should have probably checked it more often, but the diff was bone dry. Don't know if this happened as a result of poor workmanship from the last time I requested lube all the way around, or if I might have a crack, the latter seems unlikely. Anyway, IIRC I've got a D44 diff and was wanting to throw in some sort of locker anyway. Would anyone guess that I will need to replace anything other than what I would get if I went to either a locking diff or a PosiTrac system, like pinion and ring gear possibly? Is it possible that the sound could be comming from a u-joint instead? Any help would be appreciated. Thanks.

what do you mean bone dry? exactly how dry is that?

you need to have the diff torn into right away. restoring the fluid level isn't much of a solution. If any of those bearings ran dry for even a 100 yrd trip, things are likely in bad shape and need replacing. and the only way you are going to know how bad is to tear into it. pinion bearings don't take kindly to being run dry, you could have easily damaged one of those and you certainly don't want to lock up a pinion bearing, could be very dangerous!

if this diff was as dry as you implied, don't wait, <img src="/forums/images/graemlins/shame.gif" alt="" /> have it looked at immediately.

-Rob

yes, you could certainly need to replace carrier bearings, pinion bearings, axle bearings, ring and pinion, etc. depending on how dry and for how long it was run. none of these things will come with a locker.

its possible it could be something else, but the fact you said you ran this so low on fluid warrents careful inspection before you move onto to other possible sources.

-Rob

I agree with Rob... your in a situation that you need to be careful on. If you do replace the carrier, you can buy axle kits for about 150 or so depending on where you look, and that would cover all your shims and bearings.

Peter

Uggh, what I figured. I want to replace everything that needs replacement, but I can't afford a new diff right now. Is that kit you're referring to specific to certain gear ratios? Should I inquire with an Isuzu dealer? If so, which one is recommended to buy from? I'm trying to get this done as inexpensively as possible right now, but of course I want to do it right. I also don't want to end up replacing something that I am going to replace if I put in a locking or PosiTrac diff.

This is the way I see it. Your rear is toast, and a ticking time bomb..

You could either buy new bearings(even, the outer axle bearing), get a rebuild kit fro a numerically lower ratio( 3.92 carrier of something), from Randy Ring nd Pinion, richmond gear, or who ever, adn have some one set it up for you...

OR, you could go to a bone yard, adn find another rear end,same ratio, adn even find the G80(LSD), taek it home, un bolt the old one, bolt the new one in, bleed your brakes, adn your driving...

I see the second option being the cheapest, adn you will probaly spend more time locating teh rear axle, than you will replacing it...

My 2 cents.....

Chase

Let us know your location, some of us know where there are good axle..well, I can find them.....

don't forget www.car-part.com! Seems that there are some "locking" diffs out there for $250-$650.00.. Good luck!
JD

I would say it is about a grand to fix this up with a locker.

650 for an Eaton E-Locker ( I love mine) or an ARB (with an ARB you have to get some sort of air storage or compressor which is additional $$), 500 for a Detroit, (all full carrier lockers), 100-150 for a complete bearing kit). Re gearing is a great thing right now if you are going to do it, your choices are either 4.56 or 5.38 a gear set is about 120 or so. This way you can find a matching front differential. then another 200 or so dollars will go to install of R&P and the locker (yes a good shop will charge you the same to install both Ring and Pinion and locker at the same time) the grand total really shouldnt run over 1100.

It really isnt a horrible way to go although perhaps not the cheapest.

Cheapest is definently a junk yard axle.