[Rockridge]

From a leverage perspective, how much shorter could the selector lever be without having to get all Lou Ferrigno?

 

[Astro Pop]

So I assume you normally drive in 4 hi?

 

[TurnNburn]

:nono:

:whack:

2HI

Unless your offroad... then 4x4 all you want

 

[Astro Pop]

OOOHHHH...my bad. That makes sense.

 

[Mmusicman]

So I assume you normally drive in 4 hi?

No, you drive in 2-HI. Driving in 4wd on pavement causes wheel bind, and bind can damage or break the transfer case. It is said you might get away with driving on paved wet or snow packed roads, provided the tires can slip enough to not bind. I wouldn't chance it unless travel becomes extremely severe and dangerous in a massive downpour. Otherwise, 4x4 is technically not for pavement.. it is mainly for off-roading.

The NP236 however, offers manual 4x4 (with hi and lo)... as well as auto AWD (which is perfect for ALL applications). But the unit is much more complicated... uses clutches, and electronics to control the AWD. In some ways.. it's the ultimate transfer case. But it lacks the simplicity and reliability of the manual 233 case.. and it's not a simple bolt-in upgrade.

From a leverage perspective, how much shorter could the selector lever be without having to get all Lou Ferrigno?

The shifter is firm and solid, but not difficult at all (the video may give a false impression). I don't think there would be any real difficulty if the arm was a few inches shorter. In fact, the closer the cable is to the pivot point, the easier the pull would be. The trade-off is more arm travel.. but that wouldn't be a big issue if the arm was shorter... unless it put it in a bad location. Mine worked out EXACTLY as I wanted.

I measured the Liberty floor shifter arm.. and it actually measures about 12" from tip to pivot point.. longer than it appears. But the bracket on the t-case shaft is smaller, which increases needed shifting force. Yet the 231 pulls fairly easy. Must be internally designed a little softer.

It might even be possible to go into the 233 and make an adjustment to the spring on the shifter detent. But too weak might cause it to jump to another setting... who knows.

The arm I've devised works perfectly for me.
It's not hard to use, and I'm sure I could shorten it without issue.

 

[Rockridge]

Thanks for the info.

 

[TurnNburn]

From a leverage perspective, how much shorter could the selector lever be without having to get all Lou Ferrigno?

For what its worth, I don't have a secondary leverage point and mine shifts just fine

 

[90safari]

So I assume you normally drive in 4 hi?

According to the Blazer owner manual, you shouldn't drive over 55mph in 4 Hi.GM recommends if you want to go faster than that to switch to 2 Hi.

 

[Mmusicman]

-----------------------

THE ELECTRONICS

There is ONLY 1 single connection to the 233 case.

It is the VSS (voltage speed sensor) that controls the speedo, as well as controls the automatic transmission. Without this connected, the speedo doesn't work, and the trans will not auto shift. You have manual 1st and 2nd only.. drive just goes into neutral. The AWD unit had 4 connections, all unused now but one.

As I posted previously.. there is some confusion on the correct connector.
Apparently some sub-models use different connectors.

This is the connector (below) that fits the AWD (and some Blazer sub-models)
(in stock at AutoZone)

This was the INCORRECT connector for my 233...
(note horizontal pins and tab on top of connector)

It is possible to wire up the unit temporarily with female lugs (as seen here)..
but the connector and pins will not be protected from the elements.

Here is the CORRECT connector, carried in stock by Napa #LS6533 ($12)
(also carried by Rock Auto as #HP3835)
Note wider connector, vertical pins, tabs on each side...

And finally here it is installed...
(spliced into AWD wiring)

-------------------------------

Now I need to do the wiring mod for the 4-LO auto shifting.
It is NOT vital or necessary for manual operation, but is merely a nice enhancement.
Without this mod, you only have manual 1st and 2nd in 4-LO.
With the mod, you are supposed to have full automatic shifts thought all the gears in 4-LO.

For me it's not vital.. as I don't foresee needing this option much.
Most of my 4-LO pulling will be in manual low-gear anyway.

But as long as I now have an unused switch hanging from under the dash..
I might was well finish this job up will all that is available!

 

[TurnNburn]

There is ONLY 1 single connection to the 233 case.

It is the VSS (voltage speed sensor) that controls the speedo, as well as controls the automatic transmission. Without this connected, the speedo doesn't work, and the trans will not auto shift.

Good info for those who get t cases that don't come with this connector. In my experience with using and installing a dozen or so from junkyards, the used ones all but 1 came with the connectors still attached with several inches of the harness still attached (junkyards do this for quick removal, if you do this in a junkyard, do yourself a favor and do the same). The wires colors are the same, purple and green. So just match the colors for that one connector and away you go.

So I assume you normally drive in 4 hi?

According to the Blazer owner manual, you shouldn't drive over 55mph in 4 Hi.GM recommends if you want to go faster than that to switch to 2 Hi.

I think more importantly, is to not drive on dry pavement at any speed in 4hi. You shouldn't need to, have to, or want to.

 

[Mmusicman]

I think more importantly, is to not drive on dry pavement at any speed in 4hi. You shouldn't need to, have to, or want to.

EXACTLY!!! I couldn't agree more!!!

I was SO eager to "test" my new 4x4.. that I put it in 4-HI, and pulled out of my driveway. I was immediately locked in place and couldn't turn, so I backed up and disengaged. Once on my street, I "tested" the 4wd again.. only to realize more binding. Thankfully I didn't go far, and disengaged. It did stay locked in 4WD pulling back into my drive, even though the shifter was back in 2wd. Backing up again freed it... apparently a common fix. Thankfully nothing broken... except for losing a little sleep that night.

I realize now that I've thought about it.. this unit is NOT clutch driven (and forgiving) like the AWD... it is mechanically CHAIN driven, with ZERO give! Front and rears are locked in solid 100%! If the tires are not able to slip (like they would on dirt or gravel).. something either has to give, or it will break. Even when on loose or wet surfaces, there may still competing pressure between the front wheels and the back... which can cause the unit to remain locked in 4wd.. until the binding pressure is released. You can stay, but you can never leave! lol

I understand now one reason why AWD's are SO popular... they are fully automatic and impossible to screw up! They are well suited to rain and snow, and require no user activation, they just work. Manual 4x4 on the other hand, requires specific knowledge on where, where not, and how, to use it.

Forced manual 4x4 (with extra low range) is EXACTLY what I wanted and need!
I couldn't be more thrilled! I just wish I had some fun local off-road place to put it to use.
But it will get "work use" soon enough. :mrgreen:

 

[Leeann_93]

The instructions for my '86 Isuzu Trooper II included stopping, shifting into 4 hi or 4 lo, then driving only on snow or slush - not hard-packed snow, either - on pavement or on loose sand or in mud, then stopping, shifting back into 2 hi and backing up 2' or so to ensure the transfer case disengaged as it should.

That thing was an absolute beast - it didn't care when there were 28" of snow on the roads and more coming down. I had to shift into 4 hi to get it out of my parking spot, but back into 2 hi to drive - even with almost bald tires. I drove it from Centreville, MD to Dover, DE to get 2 tires put on in that snowstorm, actually - leaving 2 almost bald tires on the rear (I could only afford 2 then). In contrast, my roommate's '87 Jeep Cherokee couldn't get out of the parking spot, even in 4 lo, and he had almost-new tires all the way around. He had to shovel the Jeep out to get moving and didn't do well until he got to the paved roads.

The Trooper had a GM drivetrain, but I cannot remember what the t-case was. The 2.3L 4-cyl engine ate exhaust valves, but the 5-spd and transfer case were bulletproof.

 

[1lowcab]

my '86 Isuzu Trooper II

That thing was an absolute beast

I had one of those too! And you are right, that thing would go anywhere.
You point it in the direction you wanted to go and it WILL get you there!!

I had a buddy that put a 4.3 Gm v6 in his, it was a VERY nice upgrade and fit like it was made for it.

 

[Leeann_93]

Now I'm jealous. I hated that 2.3 but loved that truck.

 

[AstroWill]

Well done! Sticky? I think so!

 

[Mmusicman]

Thanks Will.

Well, the final chapter here (for me) was to do the VCM/PCM wiring mod.

While not essential to the transfer-case upgrade... without this mod you are limited to 1st & 2nd gear manual shifting only. This wiring mod regains FULL automatic shifting while in 4-LO.. and regains all 4 gears.

96-2000 VCM's are different than 2001-2005 PCM's.
I used the top mod shown here (for my 2000) -- using connector C4 (black), terminal 23...

I disconnected the battery before disconnecting the VCM connector.
The connector was easy to reach and unplug, without removing anything.
The cable was long enough to pull up to a working area above...

The plug must be opened up (parts un-snap and pull apart) ...

I've read that you can use a female pin from a computer connector (DB9-DB25)
(this was my biggest uncertainty.. whether I needed a male or female pin)
(I used an accy pin/wire from a Motorola radio I had available)

Here is the wiring view from behind (we want to add pin #23)

Here is my pin (pushed in though the back and snapped into place)...

And finally, I snapped the connector back together, spliced and ran the wire to an under-dash toggle switch, which switches this mod to ground.

It works perfect! The job was less difficult than it appeared reading about it.
Test drive: I now have auto shifting of all 4 gears while in 4LO.

Note: the switch should not be engaged while in standard high-range.
Naturally, I tried it to see what would happen, and the trans seemed to go into neutral or something.
I didn't want to chance it further to see what might happen.
Later on I may consider some kind of automatic switching attached to the lever or linkage.

DONE!!!

I beefed up the cable mount though the floor..

...as well as the attachment to the shifter arm...

Here's a photo of the entire cable shifter (I didn't post earlier) from floor to TC bracket...
(click to zoom)

I'm officially DONE!
Well almost... 4x4 emblems/badges are on order! :mrgreen:

 

[BadByte]

Looks good.
Have you noticed any bending of the bracket on the transfer case since it is so long?

I'll soon be swapping to an NP233 as well, but I've decided to use the Jeep Liberty shifter and cable.
Already have all the parts, just need to find the time now...sigh...

 

[Mmusicman]

Looks good.
Have you noticed any bending of the bracket on the transfer case since it is so long?

No bending whatsoever! My bracket is EXTREMELY stout.. and the cable pulls parallel to it.
You'll need to devise a bracket for the Liberty shifter just the same... or a way to mount the Liberty bracket.
I also picked up a Liberty shifter and fitted it to my bracket, just in case I decided to use it.
It's an awesome solution!
I highly recommend you mock it all up first, before you install it.

We'll look forward to seeing your progress and finished project!

 

[WinnieVan]

Cars are so cool. I love all the various tubes/lines/cables/etc. in that shot of your cable shifter.

Well done 3M! Wanna do mine next?!

 

[BadByte]

Cars are so cool. I love all the various tubes/lines/cables/etc. in that shot of your cable shifter.

Well done 3M! Wanna do mine next?!

LOL...half the fun and satisfaction comes from doing it yourself (mistakes and all else good and bad).