Gearing questions

[Marcus2000monster]

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? 

[Mopar1973Man]

LS differential is not needed. Both of my truck is standard open differential and run awesome in the snow and ice. 

[Marcus2000monster]

2 minutes ago, Mopar1973Man said:

LS differential is not needed. Both of my truck is standard open differential and run awesome in the snow and ice. 

Great thats one worry to forget. Another question is when turning in 4 wheel drive the truck bucks and hops like crazy but this is normal right?

[Haggar]

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

[Marcus2000monster]

1 minute ago, 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

When you turn. Like i said i have 3 proffesional mechanics working with me so im not worried about setting gears correctly. Other circumstances also are playing into why im doing gears only. 

Just now, Marcus2000monster said:

its not fun under the car

Thats why im doing it on the 2 post. 

[Haggar]

I have a lift too... Its still not fun.  The angle the rear axle droops to makes it a pain to put the carrier in and out for the pattern testing.  (dana 80 carriers are heavier now than they were when I was 20yrs younger...)    the angle also makes the pinion bearing outer races harder to get to.

 

Turning jumping is normal on a hard surface. (this is why i have the CAD disconnect in for 4 Lo backing.  

Reason i asked, I know 3 vehicles that somewhere during their lives, the front ratio did not match the rear ratio....  bad mechanics axle swapping without thinking?  intentional pains in the butt?  totally unsure.  but those would buck and hop in a straight line.

 

GL

 

Hag

[Mopar1973Man]

20 minutes ago, Marcus2000monster said:

Great thats one worry to forget. Another question is when turning in 4 wheel drive the truck bucks and hops like crazy but this is normal right?

 

Don't turn tight! It puts a huge amount of stress on the 4WD and breaks stuff. 4WD is meant to be used while traveling straight mostly or slick conditions where the tires can slip. When locked in 4WD and on hard pack is really rough on the transfer case. 

[Marcus2000monster]

6 minutes ago, Mopar1973Man said:

 

Don't turn tight! It puts a huge amount of stress on the 4WD and breaks stuff. 4WD is meant to be used while traveling straight mostly or slick conditions where the tires can slip. When locked in 4WD and on hard pack is really rough on the transfer case. 

Good to know. I typically rarely use 4x4. 

[Mopar1973Man]

CAD axles I really don't like them at all. On1996 Dodge Ram 1500 with the CAD axle all I've got to do is have it locked in 4WD and start pulling a bit more throttle on a grade and the axle will UNLOCK. Sucks. When you need the axle to hold locked the vacuum in the manifold drops and the CAD unlocks and now your 2WD. Then when you let up off the throttle again the CAD locks again. 

 

Now on the 2002 Cummins solid axles never have that problem. 

 

Had this on an 80's Chevy S10 pickup too. That sucked. Every time you pulling a grade the axle would unlock and go back to 2WD because vacuum would drop away. Vacuum controlled axles are a bad idea period.

[Marcus2000monster]

4 minutes ago, Mopar1973Man said:

CAD axles I really don't like them at all. On1996 Dodge Ram 1500 with the CAD axle all I've got to do is have it locked in 4WD and start pulling a bit more throttle on a grade and the axle will UNLOCK. Sucks. When you need the axle to hold locked the vacuum in the manifold drops and the CAD unlocks and now your 2WD. Then when you let up off the throttle again the CAD locks again. 

 

Now on the 2002 Cummins solid axles never have that problem. 

 

Had this on an 80's Chevy S10 pickup too. That sucked. Every time you pulling a grade the axle would unlock and go back to 2WD because vacuum would drop away. Vacuum controlled axles are a bad idea period.

Eventually id like to install the CAD switch. 

[Mopar1973Man]

Do the pull cable if you are going to keep the CAD...

[Marcus2000monster]

11 minutes ago, Mopar1973Man said:

Do the pull cable if you are going to keep the CAD...

Thats the plan.

[trreed]

1 hour ago, 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.

Its even easier than that because Spicer stamped the teeth count of both on the ring gear.  

 

Spicer puts a lot of information on their ring and pinion sets.  The pinion will have a + number engraved in that.  That number is the nominal distance you'll need to add to the installed pinion depth to set your gears correctly.  In other words, the number of shims to add.

 

Gears are not my favorite thing to set up.  I did my own, and while it's been fine, I always worry about it, even though I've checked it since.

 

46 minutes ago, Mopar1973Man said:

CAD axles I really don't like them at all. On1996 Dodge Ram 1500 with the CAD axle all I've got to do is have it locked in 4WD and start pulling a bit more throttle on a grade and the axle will UNLOCK. Sucks. When you need the axle to hold locked the vacuum in the manifold drops and the CAD unlocks and now your 2WD. Then when you let up off the throttle again the CAD locks again. 

Sounds like your check valves are failing.  CAD shouldn't ever lose vacuum, even when the motor starts to near atmospheric pressure

Edited December 20, 2018 by trreed

[NIsaacs]

If you have a choice, I would not go open diff. They use 2 pinion gears, limited slip uses 4 and the metal of the carrier is better, less cast iron. The opens are soft and can cause a carrier bearing to spin on the ring gear side, due to the torque of the Cummins. This is not as big an issue on the D-80 v/s the D-70. I think yours are D-80's so it may or may not matter to you.

[Marcus2000monster]

18 minutes ago, NIsaacs said:

If you have a choice, I would not go open diff. They use 2 pinion gears, limited slip uses 4 and the metal of the carrier is better, less cast iron. The opens are soft and can cause a carrier bearing to spin on the ring gear side, due to the torque of the Cummins. This is not as big an issue on the D-80 v/s the D-70. I think yours are D-80's so it may or may not matter to you.

D80 im not worried. 

[Haggar]

Mike,

If you lost your cad during acceleration (low manifold vacuum)  all that was wrong was the check valve before the vacuum reservoir was bad or missing...   that is an easy fix.  Don't let that be a detriment.  (beats the early GM heater type actuators)

 

Merry Christmas all!

 

Hag

 

 

[Marcus2000monster]

3 hours ago, Haggar said:

Mike,

If you lost your cad during acceleration (low manifold vacuum)  all that was wrong was the check valve before the vacuum reservoir was bad or missing...   that is an easy fix.  Don't let that be a detriment.  (beats the early GM heater type actuators)

 

Merry Christmas all!

 

Hag

 

 

Thanks you to!

[Mopar1973Man]

11 hours ago, NIsaacs said:

If you have a choice, I would not go open diff. They use 2 pinion gears, limited slip uses 4 and the metal of the carrier is better, less cast iron. The opens are soft and can cause a carrier bearing to spin on the ring gear side, due to the torque of the Cummins. This is not as big an issue on the D-80 v/s the D-70. I think yours are D-80's so it may or may not matter to you.

 

Closing in on 400k miles... I don't think it's a serious issue. 

[dripley]

I like my LS, have grown quite fond of it. I can also drift race with it.

[dave110]

Driftin' Dripley. I 'd love to see a U-Tube of that!