Locking 2:41 Differential- 2PS 6123 2

[Dirty T/A]

Looking for some general info on this differential, in a 79 TA.

What is locking? Is that a "posi- traction" rear end? Posi is limited slip, correct?

What trans goes well with this diff for street/highway driving?

Any known issues with this diff. in particular? Reliablity, dependability, ect?

Any info is appreciated. I havent dealt with a rear end in years....

[Dirty T/A]

From what I have heard, so far, this is a good highway geared differential. A 3 speed automatic is a good choice in transmission as well as the O/D trans.

I had to ask....my truck had a diff mated to a 3 speed that would scream down the freeway, due to the rear end and low gears, but never researched exactly what was in it, but made it very uncomfortable to drive any kind of distance any faster than 60.

I am still guessing that a locked rear end is a posi track.

[hoogiesngrinderz]

2.41:1 gears aren't going to get you off the line very quick at all. Locking and posi (positive-traction) diffs are really two different things, but they have become synonymous throughout the years in car lingo.

The more gears the better with that rear. Automatics are MUCH better with the lower numerical rear end ratios.

[Dirty T/A]

So what is the difference between posi and locking differentials?

[hoogiesngrinderz]

So what is the difference between posi and locking differentials?

Locking diffs will physically lock the two axles together, usually based of centrifugal force. If one side spins faster than the other an arm flings out and locks the rear into a solid unit. Posi is a clutch based unit...once the clutch is gone, well, you have an open differential.

[Dirty T/A]

Thanks for the clarification.

I have heard, in these older models, the clutches are usually already gone. We will see.

[bri2203]

From what I have heard, so far, this is a good highway geared differential. A 3 speed automatic is a good choice in transmission as well as the O/D trans.

A 1979 would not have an overdrive tranmssion from the factory. GM didn't introduce the 200r4/700r4 till 1981/1982.
A 2.41:1 gear in a non overdrive transmission would be excellent on the highway. With a stock 79 engine I don't think the transmission would tolerating staying in overdrive with a 2.41:1 gear. With a 2.41:1 rear axle .7 overdrive and 26" tires you would be turning 1,525rpm at 70 MPH

[hoogiesngrinderz]

Brian nailed it.

When I said more gears the better, I was thinking trans with a low 1st gear. I have a Muncie M20 in the Bel Air, works well with my highway gear in there.

[bri2203]

Brian nailed it.

When I said more gears the better, I was thinking trans with a low 1st gear. I have a Muncie M20 in the Bel Air, works well with my highway gear in there.

Yeap a well thought out gear selection make a big difference, Even if the car doesn't make alot of horsepower.

My Corvette used to have a 4 speed with a 3.73:1. Now it has a 5 speed with a 3.36:1. With the 1st gear being shorter you don't need a higher numerical ratio axle and with the 5 gear you have an overdrive. Of the line the car takes off better with the 5 speed and 3.36:1 than the four speed with 3.73:1.

The 5 speed is a wonderfull conversion it makes the car quicker, quieter, more efficiant, and your not spinning the engine at 3300 RPM on the hwy.

[Dirty T/A]

Thanks for the info. Its helped alot.

Going to double check which trans I have lined up.....