Astro Select Trac AWD/4x4, NP 242c build and install

FROM AWD'S TO 2-SPEED MANUAL SHIFT, IF IT LINKS THE REAR AXLE TO THE FRONT AXLE, POST IT HERE.

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

After months of research, I picked up a 242j and began preparing it for duty in my Astro. I live in snow country and was insistant on keeping some form of AWD, but needed a low range as well. What follows will be the build of the 242C (c is for Chevy, j for jeep, d for dodge; I didn't know that until I started all this)

The 242 along with the 249 are the only regularly made manual shift AWD/4wd tc that I know of. I wanted a manual shift due to the dependability as well as not having to figure out the TCCM issue (I'm not big on electrical know how). The 249 had a viscous clutch while the 242 uses an open differential lots more info hereviewtopic.php?f=58&t=7394.

For clarity sake, these transfer cases are considered to have a "full time 4wd" range setting rather than AWD, so I may use the terms interchangeably (2hi, 4hi part time, 4hi fulltime, N, 4lo).

The 249 IMHO is a better AWD system as it always has power to two wheels. The 242 in AWD ultimately has only 1wd. I chose the 242 on pure economical terms: any used 249 would require a new VC which would add ~$400 to the project. As well, if I just HAVE to have my VC back, in is easy to change out the back half of a 242 for a 249, but I'm getting ahead of myself. **EDIT** The 242 open diff is locked when in 4hi part time and 4lo.

The 242 is a common case and is available in many configurations. It was used in the Jeep Cherokee from '84 to '04 and in the Dodge Durango '89 on. A good source for what 242 was used for what, is here http://www.drivetrain.com/parts_catalog ... /jeep.html There is also a version from the Hummer but, like the 249, it has no 2wd.

To make a 242j or d into a C we must pretty much change everything that goes in and everything that goes out (all this for AWD?). Fortunately the jeep guys like putting our 4L60e transmissions in front of their tcs, so they have figured a lot of stuff out for us.

OK, that's enough typing for now. Is anybody listening? Does anybody care?
Last edited by photo_van on Fri Nov 18, 2011 6:51 am, edited 1 time in total.
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

astrozam
I have my van tatooed on my cheeks
Posts: 2770
Joined: Fri Sep 08, 2006 2:57 am
Has thanked: 1 time
Been thanked: 2 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by astrozam »

Always listening...:cheers:

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

I went with a 242j. Depending on what engine the tc was behind it might have an exposed 27 spline output like this
Screen shot 2011-11-17 at 7.53.50 PM.png
or an enclosed 32 spline output like this if it was behind the V8
Screen shot 2011-11-17 at 7.54.25 PM.png
also the front output may be a yoke or a flange.
Screen shot 2011-11-17 at 7.58.46 PM.png
Screen shot 2011-11-17 at 7.58.46 PM.png (75.46 KiB) Viewed 16255 times
Screen shot 2011-11-17 at 7.56.46 PM.png
Screen shot 2011-11-17 at 7.56.46 PM.png (98.52 KiB) Viewed 16255 times
I went with the 242jh from a 2001 Grand Cherokee V8. For one the exposed output shaft was just two weird. And two, the 32s output was going to fit my needs. No 242s have a 27 spline input required for the 4L60e.

Once you have your tc, you will need to make it work with the 4L60 mechanically and electronically. There are a few options to make it work for your Astro depending on your budget. There are two pre packaged kits for adapting the 242j to the 4L60e:

The Advanced Adapter kit $473 http://www.advanceadapters.com/products ... --50-0435/ This kit requires a change out of the TC input shaft (provided) This kit keeps the 4 inch distance between the trans and tc. Since the 242 is 3" longer than the BW4477 it will require new drive shafts front and rear (for those with the NV136 the rear shaft might fit, don't know)

The Novak package $612 http://www.novak-adapt.com/catalog/kit_4l61.htm requires (supposedly) a change out of the transmission output shaft and shortens the distance between trans and tc to 3". Overall length is 2" longer than stock (w/BW4477)

Or you can DIY it using used parts and/or a combination with some parts from the above kits.

Follow me? That's good 'cause I'm totally lost.

Next up, which parts do I need?
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

**note** This thread applies to putting the 242 into a '98 van. As I understand '99 and later may have different drivetrain components. Any reference made to later models is conjecture and you will need to confirm.

If on a tight budget (or just tight) you may wish to forgo the middle man and create your own conversion. There are three basic components you will need to convert the TC only (drive shafts and trans adapter will come later)

27 spline input shaft/gear
VSS sensor
sensor reluctor ring
_MG_7886.jpg
The sensor and reluctor are important as they drive the speedometer and tell the transmission when to shift (and probably a bunch of other stuff I don't know about)

The nice thing about the fore mentioned kits: they come with a ring that clamps to the trans output shaft and a sensor port machined into the trans adapter (more on this later)

But that would be the easy way. NV/NP transfer cases are unique in that many of the parts are interchangeable: namely the input shaft/gear. The only catch here is that the gear pitch changed around '95. No problem, just make sure your donor gear is of a similar vintage as your case.
I happened to have a NP231 sitting around that I used for donor parts (input, VSS, reluctor).

The input shafts may be of different lengths, but again that "shouldn't" be a problem.

old shaft L, new 27 spline shaft R
_MG_7885.jpg
*Selecting your 242*

As stated, I went with a "newer" V8 model because of the output splines and tail housing. I was also guessing it came with an output shaft that would accept the reluctor ring. I could never get a clear answer regarding years, but at some point Jeep went from a machined TC main/output shaft speedo gear drive to a plastic sleeve gear drive to no gear drive.

newer shaft top, older shaft bottom
Screen shot 2011-11#12BEFF2.jpg
Beside being stronger, the newer shaft will accept the reluctor ring. I was guessing the 2001 would have the newer shaft and it did. I'm also guessing that Dodge 242's also have this shaft.

Whether you use a pre made kit or DIY your going to have to pull the tc apart (unless you go with a Novak kit in which case you'll have to pull the transmission apart to change the output shaft :yikes:)

This is a pretty easy job (I haven't worked on anything like this for 30+ years and did it in my tool shed on a 2x4' piece of plywood). The only special tool you need is some good snap ring pliers. I also used an air impact to remove the front output yoke nut.

Rather than go thru the entire disassembly I'll refer you to these sites: http://www.kevinsoffroad.com/techarticl ... _swap.htmlhttp://www.jeepforum.com/forum/f13/tran ... 42-685644/http://www.jeepsrus.org/index.asp?p=Tec ... 1TCaseSwap

This is what it looks like apart, not that many pieces....
_MG_7904.jpg
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

astrozam
I have my van tatooed on my cheeks
Posts: 2770
Joined: Fri Sep 08, 2006 2:57 am
Has thanked: 1 time
Been thanked: 2 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by astrozam »

Its good to see projects of this nature being done again around here, carry on...lol :cheers:

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

Ya I guess I missed "prime time" a few years back. The ol' Astros are going away. I hope to have mine for another 10 years or so, so I guess I'll be around...
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

MountainManJoe
I have my van tatooed on my cheeks
Posts: 3088
Joined: Fri Aug 08, 2008 12:55 pm
Location: The Pacific North Wet
Has thanked: 44 times
Been thanked: 24 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by MountainManJoe »

Interesting topic. The 242 sounds like a very flexible unit. 2WD or AWD with centre differential for on-road use, and locked 4WD with gear reduction for off-road. However, I am reading that it is designed for vehicles with a GVW up to 2,500kg (5,500 lbs), even though the unit itself is quite a bit heavier than the 136. In any case, I'm looking forward to hearing about your results.

Here is something I dug up that might help you as well:
http://www.rsgear.com/articles/1994_02.pdf

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

Thanks Timeless. I hadn't seen that particular article, good info. I've read about the gear stick issue, the back up method seems to work well when needed (I need to do that in my '81 Toyota truck sometimes too).

That is weird about the 5500# GVW. The only thing I can figure is the split mainshaft/diff is a weak link (never heard of one breaking though). Other than that it looks pretty much like a 241 inside. Compared to what the Jeep people put them through, I drive like granny, so even with the extra weight I'm thinking it will be fine.
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

Though the mainshaft had the needed splines for the reluctor, it lacked the snap ring grooves.

Relutor on shaft, no groves
_MG_7873.jpg
Placement of the ring and the sensor is somewhat critical as the clearance is supposed to be .010"-.012". This can be adjusted by backing out on the sensor (more on that later)

Using a hose clamp as a guide I cut grooves with a cutoff wheel on an angle grinder
_MG_7888.jpg
I then drilled and tapped a hole in the tailshaft "bell housing" for the sensor. The casting isn't very thick, so I could only get a couple of threads. The clearance between sensor and ring was too great so I ended up removing most of the shoulder off the sensor flange. Backed off on the sensor until the gap was right, then lock tite and lock nut on the inside, RTV on the outside.

Sorry no picks of that process but this is the finished product.
_MG_7970.jpg
**About the VSS**
All the Jeep people insisted that the sensor needs to be on the trans output in order for the trans to shift properly when the tc is in low range. Silly me speculated "how can that be, my 231c had it on TC output? So I forged ahead with the above, then I randomly ran into this thread; viewtopic.php?f=21&t=1940
So the jeep guys were right, but there is a fix, and unlike the Jeep guys, (if I can figure out the wiring) my speedometer will be correct in lowrange!
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

mdmead
ASV Supporter
ASV Supporter
Posts: 2153
Joined: Sun Sep 10, 2006 6:45 pm
Location: Selah, WA
Been thanked: 1 time
Contact:

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by mdmead »

photo_van wrote:
OK, that's enough typing for now. Is anybody listening? Does anybody care?
YES! This is a conversion I'm VERY interested in. :cheers:
Matt
Selah, WA
-96 GMC Safari AWD Hi-Top Conversion -->Stalled 5.3L swap & 5" lift
-74 Ford Bronco -->Far from perfect but mine!
-99 V-10 Ford Super Duty Super Cab 4x4 -->Stock with 285 Cooper ATs
-00 Ford Focus Wagon -->The Red Turd
-95 Ford 24' Class C Motorhome -->My big block sleeper
-07 Can-Am Outlander XT -->My yellow 4x4 quad for work & play
-04 Ski Doo REV Summit -->Still several chassis behind!


No new projects until the current ones are done!
User avatar

mdmead
ASV Supporter
ASV Supporter
Posts: 2153
Joined: Sun Sep 10, 2006 6:45 pm
Location: Selah, WA
Been thanked: 1 time
Contact:

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by mdmead »

astrozam wrote:Its good to see projects of this nature being done again around here, carry on...lol :cheers:
(The good news is, in addition to photo_van here, Dean will be providing content again now that he has another van!) :muhaha:
Matt
Selah, WA
-96 GMC Safari AWD Hi-Top Conversion -->Stalled 5.3L swap & 5" lift
-74 Ford Bronco -->Far from perfect but mine!
-99 V-10 Ford Super Duty Super Cab 4x4 -->Stock with 285 Cooper ATs
-00 Ford Focus Wagon -->The Red Turd
-95 Ford 24' Class C Motorhome -->My big block sleeper
-07 Can-Am Outlander XT -->My yellow 4x4 quad for work & play
-04 Ski Doo REV Summit -->Still several chassis behind!


No new projects until the current ones are done!
User avatar

Smiliesafari
ASV Supporter
ASV Supporter
Posts: 2667
Joined: Sat Dec 02, 2006 12:34 pm
Location: Orlando, FL

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by Smiliesafari »

We know somebody else who has a project but he's too busy mowing in the snow to work on his van.
1996 Safari SLX Hotair balloon transport vehicle

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by photo_van »

Ok, let's talk about the driveshafts before we put the TC back together.

So far I've got $120 (for the 242) into the project. The 231 was another $100 several years ago and I may recoupe much of that by selling the remaining parts on Ebay.

With the existing front output yoke I would have to buy a jeep driveshaft and have a custom shaft built using that and my Astro shaft. In these parts that would run ~$300. The rear shaft would have to be shortened and have a 32 spline slip joint yoke ~$200.

The stock '98 front shaft is actually a very nice shaft that uses an (expensive) double cardigan joint at one end and a CV at the other. To use the stock shaft we will need an output flange to mount it to. We will also have to make the shaft 2" longer (or make the distance 2" shorter) more on this later.

About the time I got my TC I saw on ebay a "long style" front flange and output shaft from an older NP241c (it looked like a fit in the 242). At $50 it was more than I wanted to pay, but around what I might pay for a Jeep drive shaft.
242 L, 241R
_MG_7883.jpg
_MG_7884.jpg
Of course the bolt pattern is different than the driveshaft as is the centering ring.
_MG_7905.jpg
so you need to have your brother turn one of these index rings from an old 6" motor pulley
_MG_7906.jpg
Grooved on the back to index with the output flange step and stepped on the front to match the index hole on the driveshaft flange. Output flange is drilled and tapped to match driveshaft.
This configuration reduced the needed driveshaft length by ~1.25 inches. In hind sight I probably would used a Jeep output flange and turned a 1in long indexing adapter for that, maybe next time :muhaha:
Last edited by photo_van on Fri Nov 18, 2011 6:32 pm, edited 3 times in total.
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

LiftedAWDAstro
I have my van tatooed on my cheeks
Posts: 4379
Joined: Sat Sep 09, 2006 3:35 pm
Location: New Haven, NY

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by LiftedAWDAstro »

Great mod! Definitely watching this one.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy
User avatar

mdmead
ASV Supporter
ASV Supporter
Posts: 2153
Joined: Sun Sep 10, 2006 6:45 pm
Location: Selah, WA
Been thanked: 1 time
Contact:

Re: Astro Select Trac AWD/4x4, NP 242c build and install

Post by mdmead »

Smiliesafari wrote:We know somebody else who has a project but he's too busy mowing in the snow to work on his van.
Sounds like a guy with a few screws loose to me! (Besides, 'he' wasn't mowing, but sucking up leaves with his bagger.)
Matt
Selah, WA
-96 GMC Safari AWD Hi-Top Conversion -->Stalled 5.3L swap & 5" lift
-74 Ford Bronco -->Far from perfect but mine!
-99 V-10 Ford Super Duty Super Cab 4x4 -->Stock with 285 Cooper ATs
-00 Ford Focus Wagon -->The Red Turd
-95 Ford 24' Class C Motorhome -->My big block sleeper
-07 Can-Am Outlander XT -->My yellow 4x4 quad for work & play
-04 Ski Doo REV Summit -->Still several chassis behind!


No new projects until the current ones are done!
Post Reply