Hey guys, Been a while....

I have grenaded a Bearing or Something Worse in my 99 2500 Auto 4x4....this Rear Diff lasted me 45k..

I tow ALOT.....not severely heavy loads, but average of 8500-10k loads....

I have found a 2001 Rear Diff Complete, same Ratio, With Disc Brakes....Mine had Drum....

My Question is this...

Swapping from Drum to Disc Rear, do I need to change Proportioning Valve too, or Am I ok, just doing a Diff swap out..? or is there more to the swap I need to Know..?
I have access to the Donating Truck too....

Thanks For the Info, I been Searching, but found Nothing Yet...

John.

 

I think your best answer may come from looking up drum to disc swap for any mods that have to be done to the brake system. But the rest of it should bolt up no problem.

 

Don't know if you have an answer yet but just did mine on my 99 and I put an 01 rear end in it that was drums to disk and I deleted the proportioning valve body and just ran line straight to rubber line works perfectly I have towed with it and so far so good.

 

I would upgrade to a Dana 80... the larger bearings should last longer.

 

That's not true at all bigger bearings don't = longer life that's the job of your fluid. If you have bad fluid it will ruin bearings. And with a little help from your heavy foot and some good tourqe numbers you can mess up an 80\70 the 80 should take more but as long as you have good fluid they should both last

 

I agree on the need for good fluid... but larger bearings in a heavier, more rigid housing manage gear deflection better under load. The 70u in these trucks has Dana 60 sized bearings. (70B or 70HD were better in the bearing department) They won't last as long as they're supposed to if they're being 'cocked' off their intended rolling axis by gear deflection from constant towing.

 

Yea I see your point as well. But for the rear end them self's they really don't have alot of problems but I do agree that an 80 would be better for big loads but if its a big deal and you keep blowing rear ends you may need to look for different problems maybe better upgrades.

 

You will need a new rubber line going from the frame to the rear axle. You will also need a new master cylinder. The piece that mounts between the hydroboost and the master cylinder will need to be machined or replaced with one off of a disc brake setup. The parking brake cables for the disc won't fit in the mounting bracket on the frame as they are smaller (maybe just one and not both). A custom machined "washer" may fix that issue.

 

I literally just swapped an 01 rear diff into my 99 both Dana 70 and the 01 is disc my stock one was drum and the rubber line on the rear end hooked right up to the metal line and I did nothing with anything else on the brake system and all is well been driving it for a month now with no problems and I have towed heavy as well, with no stopping problems. The ebrake cable only the top one is to small but that can't be fixed with some custom keepers.

 

But if you don't want to make something like keepers just swap the braket with one from an 01 they hook up the same to the cable no big deal