2nd Gen Non-Engine/Transmission 99 3500 Rear End Swap to 01

[JHawk]

I want to install a newer rear end into a 3500 with the disc brakes. Actually, I am converting my 99 2500 to a 3500 and found a 01 dana 80. Want to know if the shackle mounts are the same or if anyone has considered this before. I would think that the only difference would be the emergency cable and brake lines? If anyone has helpful input, please post your comments.

 

[HillCountrykid]

I think that the porportioning vavle is different.

 

[JHawk]

I don't mean to sound dumb, but is that the anti-lock valve that is mounted on the truck? If not, could you explain.

 

[bmoeller]

They are different valves. The proportion valve controls the brake pressure between the front and rear brakes.

 

[HillCountrykid]

Like bmoeller said it controls what percentage of pressure goes to the front brakes and rear brakes. I think that the disc brake axle trucks have a proportioning vavle that lets more pressure go to the rear brakes. I may be wrong. But to take full advantage of rear brakes, I would imagine you would want to have more pressure back there than before. This also puts less stress and wear on your front brakes and pads.

 

[NScott]

About a year ago I converted a 2500 2WD 5spd to a "3500" The rear end will bolt right up with the exception of the emergency brake cables. They are a little long on the 3500 rear end, so rather than replacing them, I just got some VERY SMALL cable clamps (U-Bolts) and let the cables overlap as needed and clamped the two togerther instead of using the original cable connector. Don't forget to take your original springs off and have a spring shop add one to three springs if making this conversion. The 2500's don't have the extra leaf overload spring, and you will need more springs added if you haul/tow. Also, if you have a 5spd 2500 you don't have to change the U-joint, if you have a automatic, your best bet will be to try to get what is called a "conversion"U-joint. A good parts store can help you get one but you will need all the specs (cup size, cross length, etc. ) from your driveshaft side and your new yoke side.

 

[JHawk]

I thought that was the valve you were talking about.



My 2500 has the camper package which seems to have the same number of springs as my father's 3500. I guess this options really makes the 2500 a 3500 with consideration to the springs? My truck rides really rough right now!



I have a 5 spd, so the driveshaft u-joints should be the same. I will need to have the shaft lengthened after I stretch the frame.



Does anyone have any input on the front axle spacers?



Is the brake unit the same for a 2500 and a 3500?



How about a large capacity fuel tank? I take long trips and would like to be able to choose where I can fuel up.

 

[HillCountrykid]

I'm pretty sure that the front axles are the same, except that the 3500 has a spacer that bolts to the studs.



I was thinking about doing the 2500-3500 change, but did'nt want to spend all the money to do it right. The axle, bed, wheels and tires, and other things started to get $$$ pretty quick. It was'nt the easiest thing trying to find a 3500 rear axle with disc brakes.



Brian

 

[Snow man]

J hawk, im not 100% sure,but im pretty close that the 3/4 ton springs are 2 1/2" wide,and the 3500's are 3" wide. They look the same if you look quickly at them,but the 3500's are quite a bit beefier.

 

[JHawk]

Oh, I guess I will have to measure them!



Can anyone tell me if the gear set and posi unit is the same or different between the Dana 70 and 80?

 

[HillCountrykid]

The only 2 1/2" springs that I know of are on the Dana 60, which is on the 360 gasser model. As long as you have the camper package, I'm pretty sure the spring pack is the same. If not, they are very close.



The only two differences that I'm aware of between the 2500 80's and 3500 80's is the the 3500 is a few inches more narrow, meaning the brakes are a little different. There may be a couple more, but they are probably small.



The diffs and gears are different between the 70's and 80's.