Any 18+ GT's dailying the 4.09 rear?

[MikeHTally]

Your two posts make absolutely no sense and are contradictory. First you are talking about running the engine to redline then immediately follow up with a warning about the driveshaft spinning too fast. The rear differential ratio has nothing to do with the driveshaft RPM. Changing the differential ratio affects the half shaft and tire RPM. The driveshaft RPM is determined by engine RPM and transmission ratios. If you're worried about driveshaft RPM you must never go above 50MPH because that would make the driveshaft spin too fast, right, or do you just shift into sixth gear at 20MPH to play it safe with driveshaft imbalance?

Wow! A 3.31 ratio will turn the driveshaft 3.31 times for every turn of the rear wheels. Or, one turn of the wheels will spin the shaft 3.31 times. That applies to all ratios. A 4.56 will spin the driveshaft more times in a tire rotation than a 3.31. Motor speed will be a factor of the gear ratios in the transmission. Driveshaft RPM is totally dependent on the final differential ratio.

Sponsored

 

[DuRsT]

Wow! A 3.31 ratio will turn the driveshaft 3.31 times for every turn of the rear wheels. Or, one turn of the wheels will spin the shaft 3.31 times. That applies to all ratios. A 4.56 will spin the driveshaft more times in a tire rotation than a 3.31. Motor speed will be a factor of the gear ratios in the transmission. Driveshaft RPM is totally dependent on the final differential ratio.

lol.........and has nothing to do with the trans final drive.....??

 

[MikeHTally]

lol.........and has nothing to do with the trans final drive.....??

Correct. Trans gear will govern how fast the motor turns. 1:1 (which is rare anymore, it seems) will spin the motor 3.31 times the rear wheels' rotation (taking out driveline loss) with a 3.31 rear gear.

 

[Smokey613]

If you really want get in depth on DS alignment and physics....

 

[DuRsT]

Also.......how many of you guys depend on your differential to provide energy to move the ca

Correct. Trans gear will govern how fast the motor turns. 1:1 (which is rare anymore, it seems) will spin the motor 3.31 times the rear wheels' rotation (taking out driveline loss) with a 3.31 rear gear.

How fast does your rear end gear spin your motor?

You guys have been too much today. I'm out....I tried.

 

[Smokey613]

Wow! A 3.31 ratio will turn the driveshaft 3.31 times for every turn of the rear wheels. Or, one turn of the wheels will spin the shaft 3.31 times. That applies to all ratios. A 4.56 will spin the driveshaft more times in a tire rotation than a 3.31. Motor speed will be a factor of the gear ratios in the transmission. Driveshaft RPM is totally dependent on the final differential ratio.

^^^^^^^^^
BINGO !!

 

[Silver Bullitt]

Can one of you brilliant auto connoisseurs please explain to me the open diff component in the transmission (when in gear - not in neutral or with the clutch disengaged) that will allow the rear wheels/gearing to speed up and slow down driveshaft speed while keeping the transmission/engine speed constant? This is becoming rather comical.

 

[MikeHTally]

Also.......how many of you guys depend on your differential to provide energy to move the ca

How fast does your rear end gear spin your motor?

You guys have been too much today. I'm out....I tried.

... and failed. Gravity and momentum will spin the motor at varying speeds, depending on what gear the tranny is in. If it's in neutral, the motor will be close to idle. If my car's moving in 1st gear, my motor will be turning ~ 13.7 times as fast as the rear axle (4.17 1st gear x 3.31 rear diff gear, 14.8 times with a 3.55).

 

[Silver Bullitt]

You gentlemen are confused on the concept of drive versus driven.

 

[Smokey613]

My posts concerned only the RPM relationship between the differential and driveshaft. On normal vehicles, that relationship never changes except by changing the ratio between the ring and pinion gears.

 

[DuRsT]

... and failed. Gravity and momentum will spin the motor at varying speeds, depending on what gear the tranny is in. If it's in neutral, the motor will be close to idle. If my car's moving in 1st gear, my motor will be turning ~ 13.7 times as fast as the rear axle (4.17 1st gear x 3.31 rear diff gear, 14.8 times with a 3.55).

You gentlemen are confused on the concept of drive versus driven.

The first statement you've made that I agree with. You guys think whatever you like.

The drive (power) comes from the engine/trans, not from the diff...you guys are playing wag the dog with your premise.

 

[MikeHTally]

You gentlemen are confused on the concept of drive versus driven.

The discussion is gear ratios; pinion & ring.

 

[MikeHTally]

The first statement you've made that I agree with. You guys think whatever you like.

The drive (power) comes from the engine/trans, not from the diff...you guys are playing wag the dog with your premise.

It's a good thing you don't have to understand this stuff to get a license or buy a car.

 

[Smokey613]

And yes, I have setup ring and pinions in a differential, rebuilt standard and auto transmissions, rebuilt engines, etc. In my pre LEO years I was a full time mechanic working at Chevy and Cadillac dealerships, so I do have first hand experience in all of this. Granted, cars were far simpler then than they are today but the basics are the same. To really get off on a tangent, I once watched an older mechanic rebuild a 2 speed differential in an older 2 ton oil field truck. That thing was fascinating for the time.

 

[MikeHTally]

And yes, I have setup ring and pinions in a differential, rebuilt standard and auto transmissions, rebuilt engines, etc. In my pre LEO years I was a full time mechanic working at Chevy and Cadillac dealerships, so I do have first hand experience in all of this. Granted, cars were far simpler then than they are today but the basics are the same. To really get off on a tangent, I once watched an older mechanic rebuild a 2 speed differential in an older 2 ton oil field truck. That thing was fascinating for the time.

Working on diffs is more art than science. Black magic and voodoo. Preload, backlash, etc.

Sponsored