chicofuentes0224 Posted September 27, 2007 Share Posted September 27, 2007 Question, why does the light on the left side of my dash say "part time" instead of "full time" when I put it in 4 high? Link to comment Share on other sites More sharing options...
Pete M Posted September 27, 2007 Share Posted September 27, 2007 Because your MJ has a part-time transfercase, not a full-time 'case. Part-time means you should only drive it on slippery or loose surfaces. Full-time means you can drive it on dry pavement without hurting anything. It is possible to swap you part-time case for a full-time unit from a Cherokee. Link to comment Share on other sites More sharing options...
beaterjeep Posted September 27, 2007 Share Posted September 27, 2007 Or in other words, you have a np231 t-case and if you wanted the full time feature, you'd want to get a np242 t-case. I have one in my 86 and I absolutely love it. Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted September 27, 2007 Author Share Posted September 27, 2007 Kay, so if I have an 88 4.0 auto should there be any specific year cherokee I should pull it out of or does it not really matter Link to comment Share on other sites More sharing options...
87manche Posted September 28, 2007 Share Posted September 28, 2007 it will have to be an 87-90 era XJ, chryco switched the spline count to 23 spline when they went "ho" Link to comment Share on other sites More sharing options...
LocoJeeper Posted September 28, 2007 Share Posted September 28, 2007 I'm planning this swap come spring (have everything... just don't want to take it down until winter is over). I'm pretty familiar with the swap, just curious if this was ever a factory option (242 instead of the 231) or if I get to chalk up another "custom" point :D ? Link to comment Share on other sites More sharing options...
87manche Posted September 28, 2007 Share Posted September 28, 2007 I'm planning this swap come spring (have everything... just don't want to take it down until winter is over). I'm pretty familiar with the swap, just curious if this was ever a factory option (242 instead of the 231) or if I get to chalk up another "custom" point :D ? to my knowledge the 242 was never offered on the MJ. Link to comment Share on other sites More sharing options...
Pete M Posted September 28, 2007 Share Posted September 28, 2007 In 86 there was a full-time case offered, but it wasn't the 242. Not a single one of my brochures 87-92 mentions any sort of full-time option for the MJ. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted September 28, 2007 Share Posted September 28, 2007 In 86 there was a full-time case offered, but it wasn't the 242. Not a single one of my brochures 87-92 mentions any sort of full-time option for the MJ. Yep, Selec-trac (full-time) was 86 only, after that all there was was Command-trac for the most part. How hard would it be to take one of those Selec-trac X-cases from an 86 and stick into an 87 with the 4.0L? Manual and auto, can't decide if I want to keep manual or go auto with the next buy. Alex Link to comment Share on other sites More sharing options...
Eagle Posted September 28, 2007 Share Posted September 28, 2007 Yep, Selec-trac (full-time) was 86 only, after that all there was was Command-trac for the most part. How hard would it be to take one of those Selec-trac X-cases from an 86 and stick into an 87 with the 4.0L? Manual and auto, can't decide if I want to keep manual or go auto with the next buy. Alex Not quite. The '86 Selec-Trac was a 228 or 229 transfer case, which offered a full-time high range but did NOT offer a part-time high range. The '87 and newer 242 transfer case, which offered both full-time and part-time in high range, was also referred to by the factory as Selec-Trac. It's best to discuss the transfer cases using the numbers rather than the names, because between 84 and 2001 (for the XJ) and 86 and 92 (for the MJ) Jeep used five or six different transfer cases (with spline count changes within some of them just to make life interesting) but they only used two designations: Command-Trac and Selec-Trac. Link to comment Share on other sites More sharing options...
comanche89 Posted September 29, 2007 Share Posted September 29, 2007 what would happen if you drove a part time on dry pavement Link to comment Share on other sites More sharing options...
Eliminator89 Posted September 29, 2007 Share Posted September 29, 2007 With no differential between the front and rear axles, something would likely break. When you turn a corner, the front wheels drive a slightly larger arc than the rear wheels. They must turn slightly faster. The full-time transfercase has a differential built into it to allow this speed difference between the front and rear axles. A part-time case has the front and rear axles locked together (when in 4 wheel drive) with gears. With the axles turning at different speeds, there will be binding in the transfercase. If that pressure is not relieved, something will break. Driving a part-time case in mud, snow, on gravel, loose dirt or sand works because the slippery or loose surface allows one axle or the other to slip a tire to relieve the pressure. Dry pavement or a hard surface with good traction doesn't. A full-time case in "Lock" has that same problem. The axles are locked together in the case, bypassing the differential. A full-time case in "Lock" is for slippery surfaces only. Link to comment Share on other sites More sharing options...
DirtyComanche Posted September 29, 2007 Share Posted September 29, 2007 I disagree, but I won't get into it again. Link to comment Share on other sites More sharing options...
Oizarod115 Posted September 29, 2007 Share Posted September 29, 2007 I disagree, but I won't get into it again. lots of people have run 231s on dry pavement with no issues, which is what he's talkin bout but it's pretty much agreed that it IS detrimental to the case in the long run i'm swappin in a 242 just cause i'm swappin my 231 for 2 free ax15s ;) so why not upgrade :dunno: but there is less aftermarket for them like SYE's and lower-low-range kits Link to comment Share on other sites More sharing options...
DirtyComanche Posted September 29, 2007 Share Posted September 29, 2007 Yes, the only SYEs for the 242 are hack'n'tap style. You see no increase in strength in the rear output/mainshaft. A major weak link. And there's no upgrades for the chain. Link to comment Share on other sites More sharing options...
Oizarod115 Posted September 29, 2007 Share Posted September 29, 2007 Yes, the only SYEs for the 242 are hack'n'tap style. You see no increase in strength in the rear output/mainshaft. A major weak link. And there's no upgrades for the chain. this is a main inhibitor of most people runnin the 242... cause of this if you plan on hardcore wheelin the truck you're gonna need a 231 or even if you're just wheelin on the weekends, s&*$ happens. :roll: fortunately 231s are dime a dozen and you can usually afford to keep a spare lyin about JIC Link to comment Share on other sites More sharing options...
Geonovast Posted September 29, 2007 Share Posted September 29, 2007 what would happen if you drove a part time on dry pavement Could be like this... http://www.comancheclub.com/forums/viewtopic.php?t=6232 Link to comment Share on other sites More sharing options...
Eagle Posted September 29, 2007 Share Posted September 29, 2007 Yes, the only SYEs for the 242 are hack'n'tap style. You see no increase in strength in the rear output/mainshaft. A major weak link. And there's no upgrades for the chain. I thought the chain from a Dodge truck 242HD was considered an upgrade. And what about the internals from a Hummer 242 (242AMG)? Link to comment Share on other sites More sharing options...
mfpdm Posted September 29, 2007 Share Posted September 29, 2007 Was looking at a 99 xj in the jy today with a 242. I know it has a different input spline count, but I also noticed the rear output to the driveshaft was flanged. Question is, when did they start with the flanges instead of yokes and can they be swapped? :dunno: Link to comment Share on other sites More sharing options...
DirtyComanche Posted September 29, 2007 Share Posted September 29, 2007 Yes, the only SYEs for the 242 are hack'n'tap style. You see no increase in strength in the rear output/mainshaft. A major weak link. And there's no upgrades for the chain. I thought the chain from a Dodge truck 242HD was considered an upgrade. And what about the internals from a Hummer 242 (242AMG)? I don't know about the dodge, but the hummer parts don't fit AFAIK. Unless you swap the whole case. And the hummer case has a couple odd things about it. Oh, and if you went that route you'd have to make your own SYE (not the end of the world). Maybe the dodge case works. Dunno... But it is not rated for much more torque than the 242J. And it's rated about half of the 241HD. Link to comment Share on other sites More sharing options...
Pete M Posted September 29, 2007 Share Posted September 29, 2007 Was looking at a 99 xj in the jy today with a 242. I know it has a different input spline count, but I also noticed the rear output to the driveshaft was flanged. Question is, when did they start with the flanges instead of yokes and can they be swapped? :dunno: AFAIK they didn't. But the later model t-case had a sealed rear output with the splines just hanging out in the air instead of being housed inside the aluminum housing. Maybe the t-case you saw had a flange conversion. Link to comment Share on other sites More sharing options...
speedy Posted May 18, 2008 Share Posted May 18, 2008 So if i want to know if i have a part-time or full-time transfercase i just have to put the 4wheel drive in and look at the dash? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 18, 2008 Share Posted May 18, 2008 So if i want to know if i have a part-time or full-time transfercase i just have to put the 4wheel drive in and look at the dash? no part time has ONLY 4 selections. 2wd hi 4wd hi Neutral 4wd low full time has 2wd hi 4wd hi part time 4wd hi full time neutral 4wd low full time now, with the "full time" you ONLY run part time in dry conditions where there is no slip between front and rear. the term "full time" can be decieving. the only difference between full time and part time is that you have the 4wd hi part time, which just means that you can run it on dry pavement, or on wet/dry conditions where the road conditions vary. with either transfercase, you should never run full locked 4wd (this means run it in the 4 full selection) on dry pavement. there is no slip between the front and rear axles, and this will cause binding which will destroy the transfercase eventually. these selections are meant for conditions with slip, or "variance between axles" the light in the dash means virtually nothing. Link to comment Share on other sites More sharing options...
TNT Posted May 18, 2008 Share Posted May 18, 2008 Full time is for all road conditions and part time position is for slippery surfaces only.... The 242 case has 4wd low range part time position not a full time one.... Here is something to think about... The XJ's 242's torque rating is 1486 lb/ft, the Dodge Duango/Dakota 242's torque rating is 2028 lb./ft and the H1 Humvee transfercase has a torque rating of 2340 lb/ft. In other words a 242 can be stronger then a 231HD. The Dodge 242 will bolt up since it has the same input splines and bolt pattern. It's a drivers side drop. I think it uses a larger 241 sized 32 sline output shaft and it has the wide chain. It might need a clocking spacer to bolt it up and that should be about it. I believe a 241 SYE will fit a 242. Link to comment Share on other sites More sharing options...
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