Torqueflite 727 "clunk"

[Russ69Runner]

Can't say that is a 489 for sure those are casting number's. The best way to know is to measurer the pinion shaft will give you a closer guess to what you have. Look into the Repair and maintenance manual here. It list the different rear end chunk's. Also the pinion size. You may have to pull the chunk to see if the ring gear and pinion are worn or not. That would give you a clunk sound but should here something when letting off the gas like a whine in the rear end. These are sound's of the worn pinion and ring gear.

 

[69hemibeep]

Can't say that is a 489 for sure those are casting number's. The best way to know is to measurer the pinion shaft will give you a closer guess to what you have. Look into the Repair and maintenance manual here. It list the different rear end chunk's. Also the pinion size. You may have to pull the chunk to see if the ring gear and pinion are worn or not. That would give you a clunk sound but should here something when letting off the gas like a whine in the rear end. These are sound's of the worn pinion and ring gear.

It is a 489 the casting numbers is how they are identified.

 

[Roadcuda]

I believe this is correct and please feel free to correct me if it isn't. The picture you show is that of a 489 rear end which means you have the 8 3/4 diameter gear. To find the ratio there should be a small triangular tag under one of the bolts that hold the rear end to the axle housing. If not, one way you can get an idea of the gear ratio is to jack up the rear end of the car enough to get the tires off the ground. Put an easy to see mark on the drive shaft hear the u-joint and another on the tire. Turn the tire one full turn and count the number of times the drive shaft turns and you can get an idea of the gear ratio in your car. Let's say it shows 3 1/4 turns then it's most likely a 3:23. At the same time as you turn the tire watch the opposite tire. If it moves in the same direction you have a sure grip, if it doesn't turn, or turns in the opposite direction then it's an open rear end. I may not be an expert but I did sleep at the hotel last night!

 

[woodwiz]

I have that metal tag on one of the bolts securing the chunk. I’ve also noticed on a drive at 50-55mph that the revs on the motor seem high. I thought also on that drive I heard what may have been a deceleration whine...very slight. I’ll take more pics and search out anymore markings and get back with ya’ll....thanks!

 

[woodwiz]

Speaking of that metal tag,it is stamped 3.23,I take this is not a hwy gearing or is it?

 

[69hemibeep]

It is a good gear in my opinion. It will go down the hyw decently but not a drag race gear.

 

[Plybeep68]

Always liked a 3.23 ! Great gear, hid the speedometer needle many times with that gear ! I'm thinking when I shifted from 3rd to 4th I was already at 110 mph