I am about to buy a good used differential. It is 24 spline w/ 3 bolt Roto Flex connection to the rear drive shaft. Did the 1998 D1 come with the roto flex connection? thanx in advance..

 

I think it did, but the diff's the same. Even if it's the 4 bolt flange, you can swap your 3 bolt rotoflex flange to it if you need to.

 

1997 and 1998 came with u-joints on the rear diff.

 

Does that mean it has a 4 bolt? I probably should know, but still didn't get a chance to look under it and when it comes to anything other than the motor I am completely clueless.

Alldata and mitchel show a 4 bolt and that's what i got, the guy said i can return it if its the wrong one.

Also, Are the stock U-joints greasable?

 

Yes the stock u-joints on a DI are greasable.
Yes you have a 4-bolt, which means your drive shaft is 4 bolt as well as your output flange on the diff.
If the "new" one has a 3 bolt you can remove that one and install your 4 bolt, or you can replace the flex coupler on the "new" diff with a new one and buy a different drive shaft, the 3 bolt kind that is.
But it would be easier to just swap output flanges.

 

The one that i bought is a 4 bolt so i guess i don't have to swap anything out.

 

Nope, you should be good to go.

 

I have 1 more question. I am a little confused about this. If i read right, it says the DI has a locking differential that supposedly gives even power to the rear and front wheels 50/50. Is the differential always locked? Does it lock with the shifter? or is there something you have to do manually underneath to lock it? (its more than 1 question, i know )

 

A Land Rover is a FULL TIME 4x4.
In order to do this they need to have 3 differentials, front, middle and rear.
The sole purpose of a diff is to allow 2 things that are connected to it to turn at different speeds when needed.
So when you turn a corner the outside wheel is moving faster than the inside wheel.
Without the diff the outside wheel would skip as it was trying to spin at the same rate as the other wheel.
The center differential does the same thing, it allows the front and rear drive shaft to spin at different speeds, which happens when you turn tight corners, like when parking.
A all wheel drive car uses clutches to do this, they lock together automatically when driving straight, then they slip while you are turning.
The shifter inside your truck for your transfer case has 4 positions, all are 4x4.
Hi-unlocked, lo-unlocked, hi-locked, lo-locked.
When unlocked both drive shafts get to spin at different speeds.
When locked both drive shafts are locked together so they each get equal amounts of power and turn at the same speed.
When locked and on dry pavement you will not be able to turn a tight circle, if you try your front wheels will skip and shutter and you will bind up the drive line.
When driving on slippery roads/off road you can lock the t-case and turn the steering wheel to full lock and drive in as tight of a circle as you want, all that will happen is the wheels will slip on the loose ground and do no harm.

The t-case shifter on a Disco needs to be exercised once a month to keep it working correctly, if neglected it will freeze up and not work.

 

thank you for the thorough explanation. Basically, the only time you are gonna lock your diff is when you are off roading or very bad weather..

I was confused cause i thought you had to manually lock it from under the truck. My shifter is locked, so im assuming the previous owners barely used it or got that way from sitting there..