Ok, other than the obvious, what are the pros and cons of the two.

What gas mileage increase is there by converting? What tire were differences are there, if any? Over the years, I personally have told every one to change over... I don’t have any real on road experiences to justify this answer I have been giving.

Lets hear yours.......

I'm running fulltime now with a stock 203 case on my '77 M880 (military W200) with 318, 727, 4.10 gears. No obvious tire wear issues; I think the center diff helps a lot with that. Went from 10 to 15 mpg by removing the Carter BBD and putting on a Qjet, everything else same. :D I did use an O2 sensor to set up the carb (thread on this a while back). I've never heard anyone claim more than "maybe 1 or 2 mpg" from the parttime conversion

Engine is going back together with a suite of mods (ported 302 heads, 759 cam, headers, etc.) we'll see how that goes and what kind of adjustments the carb needs afterwards, and check mileage again. I have a 205 for the back half of a doubler, a 70 rear and a 61 front with manual lockouts to go in, so the part-time conversion may be in the future - depending on whether I break the tcase or get 35-spline stub shafts and drive flanges for the front axle (I guess which order is really the question).

I like fulltime because we have a lot of snow and ice here in winter (home is 8200 ft) and most people with manual lockouts just leave them engaged 6 mos. out of the year and shift the case as necessary. Where we live (about a mile off pavement) there's enough steep loose stuff around that I ended up engaging hubs on my old CJ about every other time I drove it (but then it had an open rear, too). Fulltime is very convenient, at least when you only need a bit more.

I think that the major benefit from the part-time conversion is losing the center diff and its locking ring. Apparently this is the main weak point in the 203 (Old Syko indicated this in the thread on fulltime 44 front axles) and it's really a pain to have it popping out of "loc" at bad times; thus the old 203 in fulltime mode is very inconvenient for hard offroad use. Yes, a bungee will help. I'll run mine as-is until it breaks, or I scrounge up enough cash to get the new axles geared, locked and under it, new tires, AND do the doubler. This could be some time (or not, depending on where I drive it in the interim ;) ).

Be aware that Milemarker has two kits for this thing; the crown gears actually make the case weaker than stock, while the full shaft makes it stronger. But, if I'm gonna fork over the cash for a new shaft, it'll be the one for the doubler.

I don't think that fulltime is all that bad, but it'll probably be a little while before I can make any quantitative comparison. Eliminating it is not a high priority for me.

break an axle, then try to drive home...........................;)

Originally posted by FULLSIZE
break an axle, then try to drive home...........................;)

Even with open diffs in both ends, if you were to break an axle, putting the tcase in "loc" would do it (if you only broke one axle) and could get out in 2wd - 'cause that's what you'd have. Thing is, without lockers the chance of breaking an axle is small because you just can't put enough torque to any one corner. Obviously this limits where you can go and how hard you can beat on it. If you do have lockers with a stock 203 then you can break up to 3 shafts and it'll still move under it's own power - if the "loc" ring holds.

With the "loc" position funcitonal, the only difference between the 203 and regular part-time cases is the OPTION to run with an open center diff - which is nice on snowy roads. Of course this begs the question of how strong that "loc" ring really is, if the intended application is as abusive as rockcrawling. Although I haven't broken mine yet, I think not very.

Even with open diffs in both ends, who still runs open diffs? :flipoff2: in my application(welded diffs front and rear) and breaking axles in a dana 44 quite offen, i have to have part time. if you dont break shafts and run an open diffs, its only a gas mileage and wear and tear issue.:D

Yeah, yeah. Remember we started building a house just over a year ago, and since then the only "wheeling" that my self-propelled dumpster has seen has been hauling supplies in, and trash out. Welded sucks on ice/snow, and I wouldn't spring for lockers until I'd determined what axles would be under it long-term. Now that I've been able to start working on the thing...

just kiddin around. i know how that goes with time to work on stuff......................;)

It's been hard to leave this one alone for that long. So much to do, so little time and money.

sounds like you've still done quite a bit of work on it.:D

I know that this is called a full time 4x, but does the front have any drive force applied when in 2X loc? (All wheel drive)

Also, when going from forward gear to reverse, what would cause a severe BANG>>>> Other than worn u-joints, worn ring and pinion, and the excessive slop in my driveline... Chain?


I guess my question is there some slop in the transmission and transfer case? Or can the chain make all that extra noise in 2x?

Sorry for the dumb questions, I could go jack every thing up and check for my self, but I don’t have time. And my book does not say… Need new book….

Thank you for the answers...

Originally posted by IH Scout II
I know that this is called a full time 4x, but does the front have any drive force applied when in 2X loc? (All wheel drive)

Not sure what you mean here. In stock form the 203 shifter has (from front to rear) lo loc, lo, n, hi, and hi loc. In all of these it drives both front and rear. In the loc positions, the locking ring is engaged which locks the center differential.

Originally posted by IH Scout II
Also, when going from forward gear to reverse, what would cause a severe BANG>>>> Other than worn u-joints, worn ring and pinion, and the excessive slop in my driveline... Chain?

That'd be my first guess. Could also be ujoint, sloppy R&P, etc.

Originally posted by IH Scout II
I guess my question is there some slop in the transmission and transfer case? Or can the chain make all that extra noise in 2x?

Sorry for the dumb questions, I could go jack every thing up and check for my self, but I don?t have time. And my book does not say? Need new book?.

Thank you for the answers...

Slop Q.
I have never tore down a 203 case, I was wondering if there is a possible loss of tolerance in side of the case some where?

The question of all wheel drive, (Full Time), if there is any dive in the front wheels during any go position.. Reason for question, is different smog check would be required.



Thanks....

RE slop - chain, and center differential are most likely candidates.

Exactly what part of "FULLTIME FOUR WHEEL DRIVE" don't you understand? Fulltime 4wd drives the front wheels ALL THE TIME. :shaking:

I found the owners manual:

HI (HIGH) Provides 4-wheel drive at the transmission gear.

HI LOC (" Lock) Locks out transfercase differential to provide maximum traction.


So I guess the smog shop will not be putting my rig on a DYNO for smog check II.. Unless they buy a second dyno for the front...

That is what I was trying to ask, just not the correct wording I guess....

Sorry...

Scout, Like Lloyd said I don't think you understand the concept of 4 wheel drive loc. If your 203 case hasn't been moded shift into Hi (not hi loc), jack up either the front or the rear wheels. chain the truck to something solid, put it in gear and try to move. It isn't going anywhere unless you put it in loc, although if you rev the engine high enough it will try to move slightly because you're overpowering the planetary in the case. You'll just spin your wheels.

I used to make people mad who would brad about full time by jacking up only the right front wheel. It would just spin that wheel until moved to loc. :D

Good to see you back, OS.

They will not want to put it on a dyno. Having said that, you CAN put it on a dyno by chaining it's ass to something immovable, and not putting anything you care about in front of it. IF that tcase differential objects to this abuse, it'll try to launch the truck through whatever's there. Having seen open-diff side gears climb up on the opposing spiders' teeth and "lock" themselves this isn't something I'd really care to try, particularly if someone else's shit was involved. If I owned the shop, the dyno, the truck, and only people as crazy as me were involved it *could* happen, but your local smog nazis certainly won't want to do it.

Should have entered that post with a disclaimer I guess:eek:
Lloyd's tellin you right. As they say severe damage or death could occur. If you know what you're doing and have a complete understanding of how the system works the afore mentioned test can be done to prove a point. For now I should have stuck to getting scout to understand the difference between hi and hi loc and lo and lo loc.:D

Even though I'm semi reitred I havn't had time to get on the board. Lookin for a position, building a new house etc.etc.etc.
Glad to see someone is still trying to educate the masses on mopar. This full time thing ain't that hard to understand nor is it weak. It is different and that seems to cause confusion.

Scout, forget the owner's manual and spend some time in a good OEM repair manual both reading, and the part I understand, looking at the pictures. One day it will all just "click"

Sorry if I got away from the original thread.

There's a huge difference between jacking up a wheel or two for a little spin, and a long hard dyno pull. :D I'd be surprised if that tcase differential would survive a rigorous dyno workout in the test I described.

Previous owner of my old CJ-5 (of which I'm now the previous owner) converted the open rear D44 to an instant-spool on a loose steep climb. After that it'd bark the inside rear on pavement, seemed to be really locked up solid. Didn't even need to pay the electric co. for the juice to weld it. It'd had enough crap get into the differential over the years that the spiders were worn and loose, and on that climb the teeth rode up and bound it solid. Eventually it popped open again.

I don't know enough about 203 failure modes to try to predict what'd happen if that kind of dyno test was attempted, but I'd plan for the worst.

I appreciate your time guys; I probably have the book at the shop, just to lazy to look... Most times you don’t see a 203 installed any thing. Every one goes 205, atlas, or Dana 20... I kind of figured it would work, as you described, just have had zero tear down time on that t-case.

I know this is a bit off subject, but have any one of you looked into that adapter that uses the 203 doublers on a 205 t-case?
How strong are the parts to adapt?


I called my smog guy, he says they gots a big dude to lift the front while they do my smog....

Actually they are going to do a old sniffer on it...

Thanks for the info guys, was a little more then expected but still good info..

Next time I will be sure to provide more info on question.

Thanks again....

If any one is interested, I found the BANG I was asking about.. The pass front axle joint is missing some needle bearings. There is a Lot of excessive movement in that joint, and the slop bangs to catch up with the rest of the axles.

I wonder how much wear has been put on the rear assembly or transfer case?

Later….