Twisted rear end yoke
I used to race my 70 occasionally at local drags and against other Corvette buddies at various tracks using G60-15 sticky DOT tires and a 3.70 rear. I never thought it hooked up particularly well but I enjoyed catching people at the top end, 113 to 115.5 mph. I took the yokes out of that rear recently and was surprised by some evidence that it was hooking up harder that I realized. Only one side was twisted.
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Re: Twisted rear end yoke
The chamfer at the end of the splines is still intact and there was little if any clearance between the spider gear shaft and the end of the yokes. What is the correct distance between the retainer ring groove and the end of the yoke?Comment
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Re: Twisted rear end yoke
Patrick-------
It appears to me that very little of the chamfer remains. Also, the end of the stub axle is worn FLAT. It was not originally flat but had a rather irregular surface (which is why there is no spec for the dimension between the end and the snap ring groove).
The case hardening of the end of these stub axles is rather thin. In this case, I feel pretty sure that most or all of it is worn through. Wear will proceed rapidly thereafter. Of course, the stub axle pictured is not suitable for re-use regardless of the condition of the end.In Appreciation of John HinckleyComment
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Re: Twisted rear end yoke
I have seen a fair share of those but usually on the mid 70's cars. The 63 to about 72 axles are better made then the later ones were. Many times I can reuse them in a rebuild and they have little wear on the face. You can install the snap rings back on and measure from the face to the ring. Original axles are in the .190-.200 range here and show little wear on the face. The rebuilt axles come in about .180-.185"
If I had to guess I'd say it was the left side that twisted?
I would recommend going with a rebuilt axle vs a "new" axle. I have seen a few of the new ones and the QC was poor. Some were not hardened on the face at all, others had the snap ring groove in the wrong location.Comment
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Re: Twisted rear end yoke
Gary you are correct. It was the left side. I am not complaining about quality. These were 60's cap type yokes, and the twist was a result of willful abuse over many years of occasional runs at the drag strip. This was not the original LT-1 rear. I removed and saved it because I got tired of the original 4.11 over 40 years ago.
The rear in question was a 69 rear that I put a 3.70 gear in.
The snap ring to end measurement of the twisted yoke is 0.182 and the other side is 0.186. I measured some old u-bolt type yokes I have and they were 0.179 and 0.186.Comment
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Re: Twisted rear end yoke
Patrick
Considering the usage if that is all that happened to that diff then you're not in bad shape. The 69's were the first year to use the newer design Eaton posi which is an improvement over the 65-68 Eaton that was used. They did have the 10-18 spiders though which are not as strong as the later 10-17's. The clutches were solid steels which are better then the 71-79 clutches or the new fiber coated clutches out today.
The LH side gets the load even with a stock posi, that is where most axles will break. A tuned posi will be better balanced but axles can still twist under load. The tip measurements are not way out of range and many times the excess end play in axles is caused by stock posi set up not as much axle face wear.
There was no difference among base, SHP, and BB differentials although some will claim there were stronger diff's used in the SHP & BB cars, I never saw it other then straps/bolts vs u-bolts for the axles. The posi cases, spiders, clutches, gears, bearings were all the same.Comment
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