ilovjeep said:
I didn't write my information down it is aw4, NP231 for both 88 & 95. Does it matter that the 95 tcase doesn't have the vacuum connection on it like the 88 had. I am not to worried about the light, but then maybe I should because I won't know it is out of 4x4 or not. Someone told me that the 4x4 will work just the light will not work. I don't know if he is telling the truth or just BSing me.
Thanks for all the help,
DR
If you don't do something about the axle disconnect, it will not engage 4WD (the transfer case will engage, but the axle won't). You have three choices here that i can think of.
The first, and simplest, would be to open up the vacuum motor, remove the fork, and shim it into the permently engaged position with washers (then of course put the fork back on). Jeepers with disco axles have been doing this for some time when presented with vacuum problems. You'll have a permenently engaged axle, just like the newer ones, though not quite as strong as the single-piece axle shaft. A tiny fuel economy and smoothness penalty is offset by simplicity. Since the 95 TC has an electric switch in it, you can wire that directly to the 4WD light and still have an indicator. You'll need a connector for the TC end, and you can then run a homemade harness up to the existing connections on the fender well that were used by the vacuum switch.
Second possibility, also very simple, might be to hard-plumb the vacuum line for "engage" to the vacuum system. You need to trust that the vacuum motor is really working well and holds vacuum. You could even run the disengage line up into the engine compartment too, and have a very primitive part-time engagement system by swapping lines, allowing you to disengage for long freeway runs etc. You could, as above, wire the switch in the 95 TC to the light. Since the 88 vacuum indicator switch is controlled by the disco motor rather than the TC, it won't be useful here. This might be the best temporary solution if you're reluctant to operate on the disco motor or pressed for time, since all it will require is a few feet of generic hose. If you don't have a light, you'll have to remember to look at the lever, but I suspect that isn't hard to get used to.
The third option would be to replace the switch currently on the TC with the vacuum switch for the older model. I'm pretty sure the hole in the case is the same, but if you have both on hand you can check that. If you have your old TC you could use the switch from it, but a new one is cheap at the dealer: under 20 bucks. If you still have all the plumbing and connectors for it, and your disco motor is known to be good this might be the way to go.
For your purposes I think the first option is probably best, because once done it should never need further attention.