70 LT1 rear end noise.

[Bob H.]

Well, I couldn't take the noise any longer and had opinions of the noise from a wheel bearing, rear end and even transmission from some knowledgeable guys. So, I propped up the rear keeping the half shafts aligned and it sounded like a wheel bearing on both sides. It really sounded like metal to metal. I took it a step further and pulled the half shafts off. Both wheels when spun were very quiet! They were rebuilt 3k ago as well the rear gears. So, I now know for sure it is the rear. I then discovered that the left half shaft was sticking out, so I pulled on it and obviously the C clamp is gone and of course floating around somewhere.

The car had sat for 8 years after restoration. There was no noise in the rear at all, but the rear was ratcheting BADLY! I changed the fluid and posi additive and proceeded to do a figure 8 when there was a loud pop, louder than the typical ratchetting. Not sure what happened I visualize the C clamp getting somewhere it should have not been. We'll be pulling it and advise what is found

[Joe L.]

Re: 70 LT1 rear end noise.

Well, I couldn't take the noise any longer and had opinions of the noise from a wheel bearing, rear end and even transmission from some knowledgeable guys. So, I propped up the rear keeping the half shafts aligned and it sounded like a wheel bearing on both sides. It really sounded like metal to metal. I took it a step further and pulled the half shafts off. Both wheels when spun were very quiet! They were rebuilt 3k ago as well the rear gears. So, I now know for sure it is the rear. I then discovered that the left half shaft was sticking out, so I pulled on it and obviously the C clamp is gone and of course floating around somewhere.

The car had sat for 8 years after restoration. There was no noise in the rear at all, but the rear was ratcheting BADLY! I changed the fluid and posi additive and proceeded to do a figure 8 when there was a loud pop, louder than the typical ratchetting. Not sure what happened I visualize the C clamp getting somewhere it should have not been. We'll be pulling it and advise what is found

Bob------


What usually happens is that the inner ends of the stub axles wear to the point that the c-clips fall off. They will usually not otherwise dislodge. When you remove the stub axle, easy now that the c-clip has apparently fallen off, you will be easily able to confirm if the end is worn up to the c-clip groove. Is this a high mileage car, known or suspect?

[Gary R.]

Re: 70 LT1 rear end noise.

A lot depend on who built it and how. Were the axles replaced? The snap rings typically will not fall off unless they were not correctly installed or worn down to the snap rings. The new and rebuild axles sold for the past 20 years are and have been suspect. While you would expect to get a good part buying from a known supplier, that might not be the case. I had a 50% rejection rate with axles. The new Chinese axles come with the cheapest snap rings I have seen, 050", that twist removing them. They don't know where to locate the groove so you may get a good one or one with 040" endplay out of the box.

How the posi was setup is another concern. Most will reuse the spring pack, some still use the cheap clutches that broke under load. Some use the new clutches that smudge away at every corner and don't work well with synthetic oil.

You have what sounds like more than the common posi clutch chatter going on there, a full break down and inspection is needed. Depending on the originality of the diff, you might have a posi case issue as 70 Eaton posi's were not the best. They were better than the 63-68's but not by much.