I just put a new rear in my 99, and the LS is very tight. Not that this is a bad thing, but I need to understand how to tell if it is too tight, because I don't want to wear it out prematurely. I put Amsoil in it with no friction modifier. There is no chatter that I can tell, at least no weird noises.
When it turn a corner if I am applying moderate power it acts like a spool, in that I hear one tire chirping a little. I don't mind this, but it made me wonder if it is too tight. My 96, with 198K, can do the same thing, but takes pretty hard throttle.

Thanks,
Chris

 

Mine's been doing that for the last 95k miles and it still leaves 2 black marks. If your worried about it being to tight then put just a little friction modifier in it.

 

IMO, thats how you want it.

I had a "LOOSE" LS on my other truck and I found that when I needed it most that very looseness made it "useless".

Big Jimmy

 

My outside tire kicks up gravel when turning sharp on a dirt road but doesn't make noise turning on pavement.
For me this seems about right using Royal Purple fluid with one bottle of modifier.

 

You must have a power lock. If it's not chattering you are good to go. It will wear in with time and should be fine. IMO I would not add a friction modifier with amsoil unless it starts to chatter in turns. Amsoil is quite slick and with smaller differentials can actually cause the differential to stop working well. Did you do the figure eight thing in a parking lot? That's when you do several figure eights on a hard surface with a new differential to move lubricant between the plates of the differential to see if any chattering developes and also to wear it in. I would do this if any chattering developes before I add any friction modifier. Nothing worst than a posi that acts like a open differential!!! It sounds like you have a good one.

 

If you are chirping tires around a corner under light load/throttle and you have a Plok, it probably needs some LS additive. The Plok should feel and act like an open diff in high traction conditions and operate very smoothly since the clutch loading is very low in these conditions. The only time the inside tire should chirp when driving around a corner is if you apply enough throttle to break traction. The Plok has VERY minimal clutch preloading compared to a Tlok so it's street manners are much smoother since it is not relying on a fixed amount of preload on the clutches. The Plok will vary clutch loading with input torque as required to keep traction.

It sounds too tight to me.......I would suggest some LS additive since this is not typical operation of a Plok unless traction is broken.

 

I have not done any figure 8's since installing the rear. I have put a few hundred miles on it though.
CTD Nut, I just want to make sure I don't loosen it up too much, in addition to not wearing it out. While I think the LS in my 96 is good, one night it was a one-wheel wonder on wet grass. I was MAD. Loading with the brakes didn't even help. But on pavement, where traction is much better to begin with, the 96 LS is just fine, only a little looser then the 99's LS. It too has Amsoil in it, with no friction modifier.
Doggone it, I want the LS to work when called to duty. Is that too much to ask?
I'm trying to find that point at the edge, just enough friction modifier to keep it from premature wear. If it wants to be a really tight LS, that's fine by me.

Thanks,
Chris

 

You should have put a Detroit Locker in and then you don't worry about tightness or additives but always is on duty when needed 100%. PK

 

I did some heavy thinking about that in another thread, but decided that the LS would be better, and more forgiving of my axles when I do heavy towing, and driving in the snow a bit easier with an LS.

Thanks,
Chris

 

While I have no experience with Amsoil gear oil, I have not encountered a synthetic that didn't need some friction modifier to make the Plok work properly, contrary to what others have said. I have always used Castrol synthetic in every Plok I have owned and have always had to add about 1 1/2 bottles of friction modifier.

Experiment.....lower the oil level in the diff by two bottles worth of friction modifier (the level will not be low enough to starve the diff). You can use a turkey baister with a bit of fuel line pushed over the end to suck the oil out if you have not other means to do so. Now, add about a 1/4 of a bottle at a time until you are satisfied with the Plok's manners. From my experience, regardless of what oil you use, you will need at least one bottle.

FWIW, no, you are not asking too much to have a great working Plok....there is certainly no need to subject yourself to a Detroit for your application! Take the time to get the friction modifier quantity correct and you will be pleased with the results.

 

CTD Nut,
Thanks again for helping. As I said, I'm just trying to figure out where that "too tight" point is. I was driving it today and turning a corner, pretty gentle on the throttle, pulling out from a standstill, I could hear the wheel chirping. I guess that means no wear is happening, if it is locked up enough to make wheel tire chirp, and I really don't mind this occurring, I just want to make sure I'm not going to wear it out.
I will see about getting at least one bottle of the friction modifier in there, and see what happens. My cover has a drain plug, so I can put that to use here.
How much modifier should be added at a time before I check it?
And "checking" it would by driving figure 8's for how long?
Then see if it still chirps the tires when turning a corner?
I would guess under harder throttle I'd want it to be locking, even in a corner, because I am applying more than normal power, which means I want to move, with maximum traction.

Sorry to be a pain here, I'm just trying to get it right,.

Thanks,
Chris

 

How do you tell if you have a Ploc or a Tloc? Mine is a realy limited slip. Seems to only lock every now and then . I can give it a lot of power around a corner in the rain on pavement and it peglegs it and at the next corner locks up with know problem and swings the back end around . I want to tighten it up so what do I do?
Thanks guys

 

You are not being a pain....I know you just want to get it right.

To me, what you describe is not acceptable performance from your Plok. There is no reason why it should be locking up prematurely like that. I can tell you for sure that there is some degree of damaging clutch chatter taking place if it operates like that - you just can't feel it. Bottom line : Add friction modifier! You WILL be compromising the life of the Plok if you don't use it. Running it too tight will eventually wear out the clutches. With the correct amount of FM, the Plok should last the life of the truck. Remember: the plok varies the clutch loading as required and does not rely on a fixed amount of preload to gain traction to both wheels. If it is running too tight in high traction conditions when turning, something is wrong!

I would suggest that you add one bottle and drive it a mile or two....then do a few figure 8's. If the Plok smoothens out and does not chirp the tires under light throttle, you are set. When you stab the throttle hard around a corner it should lock right up for you. If it is still a bit grabby - drive it a bit more.....if the problem persists, add another 1/4 bottle at a time until it is perfect. As I mentioned earlier, I would be surprised if it doesn't require at least a 1 1/2 bottles to perform properly.

 

FWIW my stock 200K mile LS still will chirp the inside tire on dry pavement if there is any gravel/dirt/loose stuff on the pavement. I have always used good dino oil and changed it regularly and added 2 bottles of FM each time. No sign of massive clutch slippage in the fluid, just what I would consider normal crud in the pumpkin. Of all of the Ploks we have had over time this one is the only one that does this and it shows no signs of wearing out so far. This is the third Plok in a Dana to reach 200K that I have had and so far all of them are still pulling strong.

If it was setup correctly it should be OK. But you might want to add some FM to see if that helps.

 

OK, I put some fiction modifier in the 99. Dunno if it works yet, I haven't driven it enough to notice.
Now I have noticed a ticking that kind of sounds like a BB bouncing around in the hub cap of my 96 when I turn sharp to the left. Could this be what chatter sounds like, and maybe I need some friction modifier in my 96 also?
Doesn't happen when going straight, and can't really tell of it happens when turning hard right, because I'm not near that window. When I apply power in the left turn I can't tell if it's there or goes away because of the engine noise.

Thanks,
Chris