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4x4 transfer question or 2

3K views 27 replies 8 participants last post by  LumaWJ 
#1 ·
Anyone know of a 4x4 transfer that will handle a V8 and not have electrical to the ECM? like pre 94? Thanks Mark
 
#3 ·
Most NP or NV transfer cases are not electrically shifted: 231, 241, 242, 249 etc. All have been used and abused behind V8s. The 231 was found in many S10 pu and blazers and is the easiest bolt up for an astro, no AWD though. People have been using the 231 manual shift in Astros for decades!

If you want awd/4wd manual shift you can use 242 or 249; I've been running the 242 for a long time. It was behind a V8 in a jeep Cherokee. Extensive write up in the old site. Be prepared for a lot of fabrication!
 
#5 ·
Many answers,Mark.The BW is non electric,except for the speed sensor for the speedometer.BUT it is not 4x4, it is AWD.I think your 89 is electric speedometer also? A 231 is manual shift 4x4,a 233 is usually converted from electronic to manual,cable or linkage,and so it goes.The thing about fit,as long as you have the trans to t/case adapter for the right year transfer case.The back of a 4l60 is the same as a 700. But,you will have to change out the output shaft of the transmission.
 
#6 ·
OK Thanks for the answer, I asked this because I may do the frame swap and leave the AWD transfer in my van till I can afford to buy a transfer from a S-10 at a pick n pull. Just in case I decide to do that I will hold onto the stock transfer. Now is there way to do the 4x4 transfer and have it so I can lock out the front axle when I wish to? Or is that not possible I am talking like I used to do with my K5. It had locking hubs but is there a way to do the same thing without the locking hubs parts? Thanks, Mark
 
#7 ·
Yes.The S10 front diff.is "split" at the rf inner axle,by a cable/vacuum unit,controlled by a vac. switch on the transfer case.That is what I have on my 94.But,also,they also make a manual cable conversion,so using the vacuum stuff is not necessary.
 
#9 ·
MechBob said:
Yes.The S10 front diff.is "split" at the rf inner axle, by a cable/vacuum unit, controlled by a vac. switch on the transfer case. That is what I have on my 94. But, also, they also make a manual cable conversion, so using the vacuum stuff is not necessary.
And that's what most of the Blazer/Jimmy/S10 guys do because the vacuum line runs under the battery tray on those trucks and gets eaten...often. So they install a manual cable instead.
 
#10 ·
More questions: If I were to go with the 231 do I need driveshafts from something else to do the swap? Can I use a home made shifter like mmusicman did with the 231? What spline count do I need to go with? Also will the adapter from the 98 between the transmission and the stock transfer fit the 231?Thanks guys/gals.

PS: I went to a local fabrication shop to bu some sections of 1/4 inch steel plate and made a friend. This guy is right into 4x4 stuff and he told me he could custom make practically anything such as skid plates, motor mounts etc. I am sure it won't be cheap though. Mark
 
#11 ·
There are many 231 configurations. You will certainly need a different front driveshaft as the BW uses a flat flange and the NP231 a ujoint yoke. you may not need a different rear shaft depending on the 231 you have. Other than cutting a hole in the floor the manual shifter is rather easy. I have a long write up on the original site under NP242.

Regarding the front axle disconnect, I think I did a write up again on the original site on how to make your own cable disconnect. Take the time to wire up an indicator light to the existing switch on the axle housing to show that the axle is engaged/dis-engaged.
 
#12 ·
Ok so according to one site I was on I may need an adapter that goes between the transmission and the transfer. Now my question is: there is an adapter between the 4l60E and the NP4472. Is this the same one for the 700R4/NP231C? It is the aluminum part the transmission mount is bolted to? Is this the same part I need?
 
#13 ·
Not to discredit all the cool and fun extra effort, uncertainty, and work of a customized installation.. one of the main reasons I went with the NP233C case is there was ZERO uncertainty and everything fits. It's a direct swap with the AWD unit. My van is my daily driver and I can not have ANY downtime. I start a job in the morning and it needs to be done by end of day. The 233 swap literally took me about an hour.. it completely bolted up to everything stock, and both AWD drive-shafts fit without any changes. NO QUESTIONS. It can even be immediately driven even without the shifter. I spent about another hour installing my cable shifter. Initial prep of the unit was done without the van being down.

Of course, converting from a RWD adds a lot of extra effort.

I think the advantage of the 231 case is that it already comes with a manual shifter arm (no need to fabricate).. but the driveshaft yokes become the issue. Of course with either unit.. you need correct rear spline count too.

The S10 axle/hub disconnect is an interesting idea.. but a little too much effort with minimal benefit, IMO.
But certainly if you have the desire to go the extra mile.. then go for it!
It is uncertain to me if this becomes a weakness in the front drive-line, or if it's even an issue.
I guess the S10 guys could answer this.

I'm just one of these guys who prefer a "practical" approach to my upgrades.
233 case is a simple and proven bolt-on upgrade (no mystery)
Simple carb'd V8 engine upgrade... (no wiring or computer mystery)
Replace these in a weekend and back on the road.
It's how I roll. :D

Have fun!

markmitch said:
Anyone know of a 4x4 transfer that will handle a V8
It's a good question. I "think" the output shaft of any 4x4 case is coupled (in direct line) directly to the transmission in high range. If so.. I doubt there would be any issues for normal use, but that's just my guess. Of course it also depends on how hard you push or beat the system under extreme conditions.

The 231/233 have no electrical connections to the ECM... nor is it absolutely needed for manual 4x4 functionality. The external switch to the ECM is merely an "option" that only "adds" automatic shifting and higher gear access while using 4-low. Additionally, the built-in vacuum switch is merely an option to lock/unlock the hubs on the S10.. which as discussed is often upgraded. Someone here posted a replacement electronic switch (on the TC) which looks like an excellent upgrade.
 
#14 ·
All good points the only reason I was thinking 231 is because I thought it was easier to do. When I was asking you about the switch to get all gears I was forgetting you have a different transmission then I am using. Mine is a 700R4 so the question was mute. After we discussed that I realized my mistake. So you were correct I just didn't understand till I finally realized the transmission difference made it so for my situation. Basically for now I will put the project together using the AWD transfer for now and worry about the swap later. This way I can concentrate on things such as the oil pan and brakes. I will be replacing the brake hoses and lines over the winter. I got the motor mounts fabricated. I added a 1/4" spacer under the trans mount to match the 1/4" I added to the motor mounts. Frame was power washed, degreased, rust reformed, primed with epoxy primer then painted and undercoated to stop rust. I replaced the front diff bushings with poly. I am having the body lift bocks made from steel pipe cause I had some 1/4 inch steel pipe the right size in my scrap pile. (1/4 is the size of the pipe walls)they will be 2.5 inches tall. This is the best time of year for me to do this since it has been low 80's all week. That's it for now. Mark
 
#16 ·
markmitch said:
All good points the only reason I was thinking 231 is because I thought it was easier to do.
Depends on your definition of "easier to do"... as well as parts and tools you have access to. Replacing a driveshaft/yoke vs making a shift arm and tapping a steel shaft. I found making the shifter arm was easy enough, and fun. 231/233 essentially the same unit. If you go with 231, be sure to get the later stronger model.

Mine is a 700R4 so the question was mute. After we discussed that I realized my mistake.
I forgot we had that discussion. Yes the 700R4 is SO easy to work with.. no electronics!
Perfect for ANY upgrade project!

I am having the body lift bocks made from steel pipe cause I had some 1/4 inch steel pipe the right size in my scrap pile. (1/4 is the size of the pipe walls)they will be 2.5 inches tall.
That's essentially how mine were made. :D

20200719_171518a-LiftPipe.jpg
 
#17 ·
Well my parts van is a 98 and my project is a 89 so I think I still may need to get 99 to 2005 driveshafts even to use the 233. But I will look into it and get the info. You got me convinced the 233 will be a better transfer and easier to find. I went to pick n pull last week and no 231C transfers out there. I also read that the 231 has some issues in the snow on the road.
 
#22 · (Edited)
could you pls explain, why is that?
I found the answer on diferent forum:
The answer as to why it isn't recommended to do this with the NV236/NV246 transfer cases is due to the fact that there are no detents for 4HI in the transfer case controls. The encoder motor has a built in brake that holds the position of the motor and shift sector shaft for a given mode. When in Auto4WD, the encoder motor will rotate the shift sector shaft and apply pressure to the front output viscous coupling in response to detected slip. This varies the amount of torque transferred to the front axle. The encoder will move and the motor brake will apply to hold that setting until the TCCM tells it to move again. Without detents, there would be nothing to hold your shift lever in position aside from you designing & fabricating a shifter assembly to do so which wouldn't be all that difficult, but does add another layer of complexity to the conversion that folks with the 3-button NV233/243 trucks do not have to deal with.

So the only way in the case of AWD is possible combination of 233/242 TC....
 
#27 ·
could you pls explain, why is that?
Yeah you’re right about not having a detent for 4HI. I just know with the encoder motor removed from the 236 you can shift it with a wrench into 2HI and 4LO. Pulling the wrench fully forward puts pressure on the packs for the 4HI/AWD. So it’s not really going to work fully as a manual shift tc.
 
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#23 ·
The ONLY way for the electronic AWD option to function properly is that it is automatically engaged when required. You can't do that with a manual shift lever. Essentially, electronic AWD is 4x4.. except it's automatically engaged. This would not apply to viscous coupling systems
 
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#24 ·
I am more Jeep guy and that is what bother me as the TC from Jeep are much easier. Sure I am not talking about TC from 2005 and younger. I will investigate if there is any possibility to take front from 233 and back from jeep 242. I do have both so I can work on it.
 
#25 ·
Unless I'm forgetting or mistaken.. Jeeps typically use NP231's, and 90-2000's GM typically use NP233's. They are essentially the same unit internally.. although the later 233 is stronger with a beefier wider chain.

Early 231 Jeep units are typically manual operation
Early GM 233C is manual electronic push-button controlled.. but usually converted to manual lever/cable shift. This mod makes the unit extremely reliable with essentially no electronic components to fail.. just pull a lever and you KNOW your are in 4x4 mode. It's fool-proof and a desirable mod.

There can be variations in output yokes and spline counts between the two units.. but the 233C is a FULLY direct bolt-on replacement using same front yoke (rear spline counts still vary by year) and need to be correct for the 99-up AWD. This make the 233C the MOST popular due to ease of upgrade, installation, and availability. No wiring or electronics needed whatsoever.

Neither of these units utilize clutch packs (which can and do fail)
Neither of these units have AWD option

AWD (when engaged) is 4x4.. and it's automatic operation is best suited for snow, and best suited for the average user. You can NOT drive a manual 4x4 on solid ground without likely damage to the transfer-case.. the AWD option eliminates this from happening and engages ONLY when appropriate and needed. You can't BREAK the AWD like you can with the manual 231/233 with improper manual activation.

Our NP136 AWD units do not have 4-low range like the 231/233 units do.
Available 4-low-range can be vital for some applications (I know this first hand)
My AWD completely failed me on several occasions pulling a load in the dirt/sand

The NP236 is perhaps the ULTIMATE bolt-on unit.. as it offers ALL the choice options (AWD, as well as manual 4x4 both high and low ranges). But the downside is the complexity of the installation, both electronics, wiring, and main unit. It's also a more complex system relying on electronic controllers, sensors, wiring, dashboard switches, encoder motors, internal clutch-packs, etc. None of these components are needed for the manual NP231/233 units.. a huge difference in reliability in my opinion.
 
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#26 · (Edited)
All above is corect, NP242 jeep TC is manual, no electric, no clutch packs nothing. Simmilar to NP231/233...
Range is 2H-4FT-4PT-N-4L..
4FT can be driven on the solid pavement
4PT is only on loose pavement
NP231 from Jeep are the same as NP231/233 from GM, only input shaft and output shafts are different. This can be exchanged. The difference betveen Jeep NP231 and NP242 is the same only guts are different. Than I assume I can get reliable TC for my Astro by converting GM 233 into Jeep NP242. But this has to be verified.
 
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