I found out today I had a Posi rear when I didnt even know it. I was feeling a wobble and rumble when turning, so I replaced seals and outter bearings, and filled with gear oil and lucas. I still had the wobble and rumble. Well now that I have found out I have a posi can I just add the posi additive or should I drain everything and fill with the additive. Or drain and clean everything with brake cleaner or something and then refill with the proper stuff?
I'd try just adding the posi additive to what you already have in there, and drive in figure 8's for a while in a deserted parking lot somewhere. If it doesn't work, there's more expensive stuff that you can try but you may have to flush it out first. Just a side note, I noticed yours doesn't use coil type pre-load springs. Mine used to do that and no matter what I did the only thing that eliminated the chattering was installing lighter springs between the clutch packs. I even tried new clutch packs. I think mine may have worn spider gears though, but I couldn't find new ones that would fit. ou: I ended up using synthetic gear oil with the additive and no problems so far.
Remove some of the gear oil (old turkey baster and rubber fuel line) and add limited slip (posi) additive to eliminate your clutch chatter. Simple enough.
OK, here's what I'd do, assuming that the gear lube you've had in the rear end is NOT posi gear lube. I'd clean out as much of the old gear lube as possible, then put in posi gear lube with the friction modifier additive in addition. But it's quite possible that the gear lube you've been using is for a posi, since most of them now are supposedly for either posi or open, as I recall. If you can determine what's in there now (like maybe the original container for the lube) and it's a posi gear lube, you don't need to do much other than add the friction modifier. Of course, you may find out that is isn't even the rear end that's causing the original problem you asked about!! But hey, it's always nice to discover that you've got a posi.
I kept the gear oil container. I had bought a gallon so I didnt use it all. On the back it says "Limited Slip - For top up only" So I guess its not for a posi. I'll pick up a new cover gasket this weekend (well maybe next cause its easter and the wife has so much stuff planned) and get some posi gear oil and the additive from the GM dealer. Keep you fingers crossed
Don't use any solvents in there. Just clean it out with lint free rags. Go to any GM dealer, and ask for "Limited Slip Axle Lubricant", part number 1052358. This is a 4 oz. bottle. Add one bottle to the rear end, and then fill with a good quality 75w-90 geal oil.
Sounds like a plan. I'll keep everyone updated I posted here a while back about why I couldn't spin my tires. I guess the posi answers that question too...
You should be OK......limited slip and posi are the same thing....."standard" differentials are what's different, they are one wheel peel. :TU:
Because it says Top Up Only I took that to mean I could top up the gear oil but not use it to fill it. I think I'll drain it anyway, and put the right stuff in there with the additive. Thanks guys! I'll let you know what happens.
i ran mine with no additive for many years with no problems but i am running sythetics so that might help alittle noise on the auburn around slow corners but nothing as loud as my spool
Picked up Mobil Synthetic 75-90 and got a couple bottles of GM additive. Drained it today, letting it drip to get the rest out of the bottom of the diff. I figure the posi gears are not factory I can see a "66" painted on the pinion, you can see the yellow paint here. I also picked up some NeverDull polish and it did quite a job on the bumper! I will put the cover back on, add 1 bottle of additive, and fill with synthetic oil. Ill keep you posted...
Re: Learned today I have a posi - I had regular gear oil in there! - Updated Drained the diff and let it drip for a few hrs. Cleaned out as much as I could. new gasket, and re-installed the cover. 1 4oz bottle of GM Limited Slip additive top up with Mobil 75-90 synthetic Noise and wobble are gone! The help from this board is amazing.. Thanks guys :3gears: :beers2: :3gears:
Tailpipes? Beautiful car. I have never saw any tailpipes like that. If those are crimps where the pipe was bent I would think it would be restrictive. Bert
Re: Tailpipes? Those are crimps on the bends. I assumed that was what a factory pipe looked like. The plan is for a 2 1/2 mandrel bent x system but. Its on the list but just not at the top. I wanna get my distributor done by Dave first, then when I get my stock exhaust manifolds machined, Ill also try to swing the new exhaust. Might need a new set of tips then too. All it takes is money.
