Non disco D30 in a '90 4.0 ??

I thrashed my disco 30 so i swapped in a non-disco front and put an 8.25 where the D35 was.
This kinda got me thinking. What will happen if i put my Aussie back in the front? Does the 1990 NP231 have a true neutral or will i be in constant 4WD?

I just seem to remember reading that the 231's were different pre/post Renix (?)

It's the sam t/case. Was used with and without disco throughout the years.

It should not affect 2WD operation, in which, as far as I know, all NP 231 cases unlock the front driveshaft.

However, "the same t/case" is also not quite correct, as I learned during a protracted debate here a few years ago, which ended with me eating a big helping of crow after assuming that all 231's behave like the 89 I had in front of me.

Early versions of the NP231 lock the two driveshafts together in neutral. The 89 version does this. Later ones do not. The one I just took out of my 95, for example, does not. I don't know if this is pre-post Renix, or pre-post disco, or what the division is, but it's definitely a difference. It should not affect driving, but might affect flat towing.

Thanks.
Are you sure this neutral issue only affects the '89, not including my '90 ?
Guess it would be as simple as putting the T-case in neutral with the front wheels in the air and spinning the front d.s...

My main concern was streetability tho. I just found out that the 8.25 i put in the rear has trac-loc so adding an Aussie to the front should really get the traction going

Norwegian said:

Thanks.
Are you sure this neutral issue only affects the '89, not including my '90 ?
Guess it would be as simple as putting the T-case in neutral with the front wheels in the air and spinning the front d.s...

My main concern was streetability tho. I just found out that the 8.25 i put in the rear has trac-loc so adding an Aussie to the front should really get the traction going

Click to expand...

I do not know when the change was made. If I were guessing, I'd guess the 90 has the older style, and that the change occurred when the disco was dropped, but as you say, it's easy enough to test. One wheel in the air should be enough.