Rear Axle Keeps Locking Up

[Scruffy49]

3.73 or 3.55, with a leaning towards 3.73. 218s are rather anemic... Good enough engines (the 1st 2 in my truck saw over 330K combined miles of service) but stone gutless in stock trim.

[David A.]

I would not recommend it, but I ran a 2.76 rear end out of a 1968 Chrysler New Yorker in my 1950 B2B with its original tired 218 for almost 20 years. It had no power, but it did get me where I wanted to go. I even drove it from Greer, SC, to Wachapreague, VA, then through the hills of Pennsylvania to the little town of Millerstown, PA, and back home to SC. It struggled in the mountains, but still did surprisingly well at interstate speeds. As I recall I was running with interstate traffic with my speedometer reading between 35 & 40 MPH! I have been in the process of restoring it for the past 6 years or so and I have put my original rear end back in. I replaced the 4.10 pumpkin with a 3.54 out of a Plymouth. I am looking forward to the day when I can try it out!

[Merle Coggins]

You're engine isn't screaming as much as you think it is. I just went through this with Mark (ggdad1951). When he was at the point where he thought his engine was nearly maxed out I could tell that he was really around 2500 RPM, comparing the sound to my truck which has a tach. With 3.90 gears you should easily be able to run up to 60 MPH.

 

That being said, I'm quite happy with my 3.73 gears. I've documented this in previous posts, but at 65 MPH I'm running around 3100 RPM, and there's room to go. A 3.54 gear set would drop that some, but I'd be concerned with the available power when pulling some of the hills around here. I guess it depends on the terrain in your area.

 

Merle

[flathead]

I would not recommend it, but I ran a 2.76 rear end out of a 1968 Chrysler New Yorker in my 1950 B2B with its original tired 218 for almost 20 years. It had no power, but it did get me where I wanted to go. I even drove it from Greer, SC, to Wachapreague, VA, then through the hills of Pennsylvania to the little town of Millerstown, PA, and back home to SC. It struggled in the mountains, but still did surprisingly well at interstate speeds. As I recall I was running with interstate traffic with my speedometer reading between 35 & 40 MPH! I have been in the process of restoring it for the past 6 years or so and I have put my original rear end back in. I replaced the 4.10 pumpkin with a 3.54 out of a Plymouth. I am looking forward to the day when I can try it out!

 

2.76 WOW! Well I am not looking to travel much, it's just that where I live it's fairly rural, and all the car events are 15 to 50 miles (and more!) away, I want to be able to hop on the highway, and not take the back roads. Maybe even drive to work sometimes!

You're engine isn't screaming as much as you think it is. I just went through this with Mark (ggdad1951). When he was at the point where he thought his engine was nearly maxed out I could tell that he was really around 2500 RPM, comparing the sound to my truck which has a tach. With 3.90 gears you should easily be able to run up to 60 MPH.

 

That being said, I'm quite happy with my 3.73 gears. I've documented this in previous posts, but at 65 MPH I'm running around 3100 RPM, and there's room to go. A 3.54 gear set would drop that some, but I'd be concerned with the available power when pulling some of the hills around here. I guess it depends on the terrain in your area.

 

Merle

With the 3.90 and what size wheels and tires, what is the RPM at 60mph? right now I have 15's with 7.50 on the rear

[TodFitch]

2.76 WOW! Well I am not looking to travel much, it's just that where I live it's fairly rural, and all the car events are 15 to 50 miles (and more!) away, I want to be able to hop on the highway, and not take the back roads. Maybe even drive to work sometimes!

With the 3.90 and what size wheels and tires, what is the RPM at 60mph? right now I have 15's with 7.50 on the rear

One reference I found for 15" 7.50 tires listed a mounted diameter of 30.9 inches. Assuming yours are similar, I plugged that into my calculator at http://www.ply33.com/Misc/speed#calc and I come up with 60 MPH being about 2500 RPM using a 3.9 rear axle.

 

For what its worth, I use 3200 RPM as my long distance cruise speed on my '33. Using that rear axle and tires that would be 75 MPH.

 

Difference in travel time for a 30 mile trip between 50 MPH and 65 MPH is 8 minutes. For me, going to a car show or even to work that is not a big deal. I guess the drivers in Washington must be less tolerant of an old slow poke car than here in California. I've never had an issue with people when I get on the freeways even if I'm maintaining 55 or 60 instead of 70 or 75.