sure-grip
Posted: Sat Dec 04, 2004 9:22 pm
Hello,
The 59 Plymouths had many options, one of which was the SureGrip rear end (also known as positraction).
I have one of these units lying on the garage floor. I would like to determine its "ratio". Somewhere I have my Manuals, but frustratingly, we have moved to a new house and all my stuff is in boxes..somewhere!
I seem to recall from reading in the 59 Supplement that there were two ratios of SureGrips available.
I made a mark in the spot where the axle connects, then I counted how many times I had to turn the input shaft to get one revolution at the output shaft..it was 3 1/3. Is it therefore obvious that it is a 3:31 SureGrip? If it is, is that a good all-around ratio?
The problem I am having is this: my car sounds like a jet engine at speeds over 55, AS READ OFF THE DASH SPEEDOMETER. I am pretty sure the speedometer is reading 10 mph LOWER than true speed, since I am being passed all the time, which makes me think the previous owner changed the rear end gears to something that would allow him those quick starts "off the line". This leads me to further think that they must have had to offer different speedo gears in the tranny for different rear end ratios. (Or maybe Plymouth just didnt care?)
I plan to crawl under the car and look for stamped numbers or a tag on the rear end case..if that is inconclusive, I can jack up the rear of the car and determine the ratio by rotating the wheels and counting the driveshaft revolutions. Lastly, I can open up the rear end case and count teeth.
Any comments or facts folks can add to assist me here will be most welcomed.
Roger
The 59 Plymouths had many options, one of which was the SureGrip rear end (also known as positraction).
I have one of these units lying on the garage floor. I would like to determine its "ratio". Somewhere I have my Manuals, but frustratingly, we have moved to a new house and all my stuff is in boxes..somewhere!
I seem to recall from reading in the 59 Supplement that there were two ratios of SureGrips available.
I made a mark in the spot where the axle connects, then I counted how many times I had to turn the input shaft to get one revolution at the output shaft..it was 3 1/3. Is it therefore obvious that it is a 3:31 SureGrip? If it is, is that a good all-around ratio?
The problem I am having is this: my car sounds like a jet engine at speeds over 55, AS READ OFF THE DASH SPEEDOMETER. I am pretty sure the speedometer is reading 10 mph LOWER than true speed, since I am being passed all the time, which makes me think the previous owner changed the rear end gears to something that would allow him those quick starts "off the line". This leads me to further think that they must have had to offer different speedo gears in the tranny for different rear end ratios. (Or maybe Plymouth just didnt care?)
I plan to crawl under the car and look for stamped numbers or a tag on the rear end case..if that is inconclusive, I can jack up the rear of the car and determine the ratio by rotating the wheels and counting the driveshaft revolutions. Lastly, I can open up the rear end case and count teeth.
Any comments or facts folks can add to assist me here will be most welcomed.
Roger