projectresto83

I have a c5 tranny with a 7.5 rear in my 83 that was a sixer and now I have a 306 in it. Whenever it shifts into 2nd hard or when I put it under hard part throttle like when taking off from a stop light quickly it makes a grinding noise somewhere from the rear. I popped off the diff cover and all the teeth on the diff are in perfect shape but it doesn't sound like those teeth are the ones grinding. It sounds more like a bunch of little splines such as the ones on the axle slipping in the carrier.Has anyone seen those slip from time to time and slowly get worse? I didn't see any shavings in the housing when I drained the fluid but I'm thinking it may have all when into the drain pan with the oil. Or maybe it would be the flange that bolts to the pinion and those are spinning (I doubt). The rpms do go up about 400 rpms or so till I let off or it catches. I was told maybe the discs are slipping too. When that happens does could it grind like that? Yes I know a vid or sound clip would help but the car is on stands for now till I figure it out. What do you guys think????

mjr46

hard to make a guess without a ride in it to feel what your experiencing.....but check u-joints for roughness or binding and if in fact it is in the reaar ..you'll have to disassemble it and inspect it piece by piece[:@]

projectresto83

Yea, I have thought about pulling the axles out and checking the splines and see what they look like. There isn't any play in the u joints. At first I was thinking that it was the tail pipe hitting the control arm because it does ride close together and it started after I welded up the passenger side pipe. But there isn't any indication of it hitting or rubbing and if it was the rpms would go up some and then drop back down when it stops.I figured it would be hard for someone to tell me what they think without being here but I tried. I am about to just put the cover back on and deal with it until something gives out. Just gives me a reason to swap to an 8.8.
Hey Mjr, know what really sucks, I finally got my plates and got to drive the 83 to work the other day and burned thru almost a whole tank of gas in one day[:@]. It wasn't complely full but work is 14 miles one way and I made 6 of those trips. So maybe 8-10 miles to a gallon at best.....................but my foot was thru the floor with alot of that driving lol. I know that killed it. And I need a new cap, rotor and plug wires so that doesn't help either.

projectresto83

Anyone else have an idea on this??????????

mjr46

last year when I took a trip from my house in harpers ferry wv to allentown pa where cj pony parts is for their customer appreciation day I drove my 85 with the 11 to 1 306 at the time and suprisingly with the 650 double pumper on it.. I got almost 250 out of a tank of gas.....so I figure I was getting close to 15 mpg.. not to bad for not having messed with the tune on the carb to much

projectresto83

I still have alot of tweaking to do with the carb once I get the ignition situation straightened out, but my plugs are a very light tan to white so I am not running rich. I just need to spend a tank just cruising and see what happens.My fuel sending unit doesn't work right either so I don't know exactly how much I have left. It reads empty when it has anything over 1/2 tank and full when it is empty. I already tried swaping the two wires on the sending unit to see if it works in the right direction but it didn't help. It worked fine until my brother traded a friend of his the stock tank for an efi tank years ago. Would having a 87+ sending unit not work correctly with a 83 gauge?? Are the resistances the same for the gauges or did they change them from one style cluster to the next? If that is the case I know I need to buy the correct year sending unit and not just a 87-93 unit.