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As you guys know I’m about to dive into a gear swap. I have been planning to swap the entire axles in but at this point for sake of time and being I have professional mechanics by my side I’m going to do just the internals. My question is that I’m not 100% sure that the axles I got are 3:54 ratio. They came out of a 98.5 5 speed. Did they ever put 4:10s in a 5 speed? Also I’m concerned that the 3:54s are not LS differentials and is they’re a way to convert it to LSD without need for a 600$ locker? Can you just buy a used 3:54 carrier? 

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Just now, dripley said:

damp pavement is easy to drift if you aint careful getting on the interstate,

I pulled my gears out of the parts truck tonight. They are verified 3:54s non LSD

24 minutes ago, dripley said:

damp pavement is easy to drift on if you aint careful getting on the interstate,

Might be the tires you run.

chicken tire.jpg

If I could just get 4 it would help.

This place has them. Word has it there's a 10% discount for Chicken Men.

OK, I'll stop now. I've fowled up @Marcus2000monster's thread enough.

Merry Christmas to everyone!!

rooster tire.jpg

Edited by dave110

  • Owner
10 hours ago, Marcus2000monster said:

I pulled my gears out of the parts truck tonight. They are verified 3:54s non LSD

 

Remember you have to change the front axle too. Other than that the 4WD with blow that transfer case up.

  • 2 weeks later...
  • Author

Well I successfully completed a gear swap. Truck is way different! Better torque curve better low end power lower rpms etc. I’m very happy so far!

  • Owner
21 hours ago, Marcus2000monster said:

Well I successfully completed a gear swap. Truck is way different! Better torque curve better low end power lower rpms etc. I’m very happy so far!

 

Told you. Now you understand why I went to 245s tires. Changed the final ratio to optimize power.

  • Author
5 hours ago, Mopar1973Man said:

 

Told you. Now you understand why I went to 245s tires. Changed the final ratio to optimize power.

Yep I feel bad for the dudes still running 4:10a with huge tires. 

3 minutes ago, Marcus2000monster said:

Yep I feel bad for the dudes still running 4:10a with huge tires. 

Did you go to 245's also? Dont think I will ditch the 265's. Very good for the highway empty.

  • Author
9 hours ago, dripley said:

Did you go to 245's also? Dont think I will ditch the 265's. Very good for the highway empty.

No . Still running 285. I will be stepping down to 265 though next time I need tires

  • Owner
1 hour ago, Marcus2000monster said:

No . Still running 285. I will be stepping down to 265 though next time I need tires

Got to 235/85 R16. Same height on the 235s but narrower. If you off-road a lot run the 265 for flotation. 235s are great for the ice and snow. 245s are great on 3.55 gears too.

18 hours ago, dripley said:

Dont think I will ditch the 265's. Very good for the highway empty.

Same here, going from 285 to 265 hurt me a little crusing at 75, I now have to cruse at 70 or less. But going 60,65 is way better on mpg. 

On 12/20/2018 at 7:10 AM, Haggar said:

To verify your new ring and pinion ratio, just open the cover. 

Count the number of teeth on the pinion.  Count the number of teeth on the ring gear.

 

Divide the number of teeth on the ring gear by the number of teeth on the pinion.   This is the gear ratio of that pair.

 

It is certainly possible to get the 4:10 with the 5 speed.  I am sure it was an option. 

 

Axle swap would still be faster.  Its better to have the axle out to get the gears set anyway.  (its not fun under the car doing the ring and pinion.  it can be done, just did my brother 70U, but in hind site i should have dropped the axle. 

 

I am like mike, the LS is not needed, but nice.

 

Hag

hops and bucks in a straight line, or only when  you turn?

 

Hag

Can't you just rotate pinion 3 1/2 times and mark wheel rotation?  Saves opening the case up?

Edited by Blueox01

3 hours ago, Dieselfuture said:

Same here, going from 285 to 265 hurt me a little crusing at 75, I now have to cruse at 70 or less. But going 60,65 is way better on mpg. 

I can still make 19.5 mpg at 75 on the interstae. 7 to 9 hours on Friday and back again on Sunday does not leave much room for much 60 mph driving.

 

What makes you have to cruise at less speed?

1 hour ago, Blueox01 said:

Can't you just rotate pinion 3 1/2 times and mark wheel rotation?  Saves opening the case up?

 

Yes and no.  In your example the following will be true:

 

If you have limited slip, block the front tires, place transmission in neutral and raise both rear tires off of the ground.  With both rear tires rotating together for one revolution, the driveshaft will rotate 3 1/2 revolutions.  

 

If you don't have limited slip, block the front tires, place transmission in neutral and raise one rear tire off of the ground.  Rotate that tire two revolutions and the driveshaft will rotate 3 1/2 revolution.  

 

- John

5 hours ago, dripley said:

I can still make 19.5 mpg at 75 on the interstae. 7 to 9 hours on Friday and back again on Sunday does not leave much room for much 60 mph driving.

 

What makes you have to cruise at less speed?

My instant mpg meter on qwad just drops like a rock if I'm above 70 and it's very accurate now that I got it dialed in. It seems im constantly trying to build boost even going slight down hill. It could still be in my tuning, but don't think so. I'm close to 20 timing at 70mph summer was closer to 22 and I played with it too to see if there is much change, not really, which is wired. I need to drive it more and play with settings,  I had it working good right before it cooled off and now chasing ghost. I'm not too worried as I know it'll come around. I didn't just gave up my 285s to have crappier mpgs at 75 with 265 so I'm determined to figure it out, just taking my time. 

12 hours ago, Tractorman said:

 

Yes and no.  In your example the following will be true:

 

If you have limited slip, block the front tires, place transmission in neutral and raise both rear tires off of the ground.  With both rear tires rotating together for one revolution, the driveshaft will rotate 3 1/2 revolutions.  

 

If you don't have limited slip, block the front tires, place transmission in neutral and raise one rear tire off of the ground.  Rotate that tire two revolutions and the driveshaft will rotate 3 1/2 revolution.  

 

- John

I understand what your trying to articulate, but why would you spin the tire and not the pinion? The pinion gear powers the ring gear not visa-versa.

1 hour ago, Blueox01 said:

I understand what your trying to articulate, but why would you spin the tire and not the pinion? The pinion gear powers the ring gear not visa-versa.

 

The ratio works both ways, so either method is fine.  If you were doing the test outside, you may not want to be laying under the truck in a puddle of water rotating the driveshaft.

 

- John

4 hours ago, Tractorman said:

 

The ratio works both ways, so either method is fine.  If you were doing the test outside, you may not want to be laying under the truck in a puddle of water rotating the driveshaft.

 

- John

True but Marcus2000Monster was replacing (from my understanding)a complete Differential from 4.10 to 3.54, that was supposed a swap, so it was out of the truck, my comment was why open differential to count teeth vs rotating pinion.

On 1/2/2019 at 5:26 PM, Marcus2000monster said:

Well I successfully completed a gear swap. Truck is way different! Better torque curve better low end power lower rpms etc. I’m very happy so far!

Did you replace the whole diff? or just the ring/pinion?

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.