Stupid 4wd ?'s

[maddzz1]

This is my first 4wd. I have an 89 MJ. Manual says to shift into 4H anytime below 35MPH.

 

Can I shift into 4WD if the truck is stopped, like when I walk out in the morning and there is 10 inches of snow in my driveway?

 

Should I be stopped or driving a certain speed to switch back into 2WD?

 

Is it bad to drive on the highway in 4H?

[Wildman]

Well, if you have a '89 MJ, you'll have the NP 231 for a transfer case, and that is a 'Shift on the Fly' type case.

 

Yes, you can shift from 2wd > 4wd high from a dead stop, moving, anytime, Just not at high speeds, like 65 mph, you can shift from 4wd high > 2wd the same way. You Need to come to a complete stop to shift to 4wd Low. and stoped to shift out of 4wd Low.

 

Don't drive on DRY pavement in 4wd, the front and rear wheels Need to be able to slip some what or you'll bind up the transfer case and blow that out.

[maddzz1]

Thanks.

[FxRacing282]

wildman, i disagree, ive done 70 and went into 4wd and driven on the street and all that in 4wd, no stretched chain no craks nothin. but not saying its good. maddzz1, if there is snow on the road or anything along those lines, feel free to drive in 4HI

[JeepcoMJ]

wildman, i disagree, ive done 70 and went into 4wd and driven on the street and all that in 4wd, no stretched chain no craks nothin. but not saying its good. maddzz1, if there is snow on the road or anything along those lines, feel free to drive in 4HI

 

I beg to differ

 

 

 

you must have gotten lucky. that detonation happened at 45mph shifting on the fly, and the t-case had brand new, topped off fluid. talk about bind at high mph...every time you shift at that high of speed, you risk what you see above

[TNT]

I have a 242 case with a non-disconnect front axle and can shift from 2 hi to 4 hi to 4 fulltime at speeds up to 70mph(I never tried it going faster). All it takes is a blip or two on the throttle after shifting. It shifts worse at speed below 20mph, it tends to take quite a bit longer.

 

If you have a disconnect front axle with a 231 the above doesn't apply to you.

 

I prefer to shift from hi to lo range at about a slow walking pace in neutral, it slips right in.

[Geonovast]

wildman, i disagree, ive done 70 and went into 4wd and driven on the street and all that in 4wd, no stretched chain no craks nothin. but not saying its good. maddzz1, if there is snow on the road or anything along those lines, feel free to drive in 4HI

 

You got lucky. If there is ANY difference in diameter between your front and rear tires, then you're gonna break something. Unless you have Full Time, which will have a viscous coupling, therefore allowing the axles to sping at different speeds.

[carnuck]

wildman, i disagree, ive done 70 and went into 4wd and driven on the street and all that in 4wd, no stretched chain no craks nothin. but not saying its good. maddzz1, if there is snow on the road or anything along those lines, feel free to drive in 4HI

 

You got lucky. If there is ANY difference in diameter between your front and rear tires, then you're gonna break something. Unless you have Full Time, which will have a viscous coupling, therefore allowing the axles to sping at different speeds.

 

Unless a 242 was swapped in, the only year with factory full time was '86 4 cyl or 2.8 V6 with NP229.

[JeepcoMJ]

Unless a 242 was swapped in, the only year with factory full time was '86 4 cyl or 2.8 V6 with NP229.

 

the 242 was also available in comanches, it's just rarely seen

[CWLONGSHOT]

Lots of stupid careless things have and will be done, doesnt make them right or correct.

 

Follow your manual, stay out of 4WD on dry pavement. Shift on the fly to about 40mph only. I prefer to shift onto 4lo only at a stop, in neutral. A VERY slow roll is acceptable if you have a problem shifting.

 

JMHO,

CW

[Oizarod115]

wildman, i disagree, ive done 70 and went into 4wd and driven on the street and all that in 4wd, no stretched chain no craks nothin. but not saying its good. maddzz1, if there is snow on the road or anything along those lines, feel free to drive in 4HI

 

You got lucky. If there is ANY difference in diameter between your front and rear tires, then you're gonna break something. Unless you have Full Time, which will have a viscous coupling, therefore allowing the axles to sping at different speeds.

 

242 is differentiated, no viscous coupling... thats the 249 i beleive.

[Pete M]

Unless a 242 was swapped in, the only year with factory full time was '86 4 cyl or 2.8 V6 with NP229.

 

the 242 was also available in comanches, it's just rarely seen

 

Gonna need some evidence of that... :cheers:

[Eagle]

Differentiated or not, when you shift a 242 from 2WD into 4WD you go first into 4 part-time, and THEN into 4 full-time. It is best to limit the speed at which you shift to what the owner's manual says, or a bit less. Also, keep your foot and neutral throtlle when making the shift, dom't shift when applying power or coasting under compression braking.

[akamcbird]

so what is the top speed 4wd should be used (not shifted just used)...231??

 

also don't let your rear tires spin while shifting into 4,your front and rear tires need to be turning at the same rate.

[whowey]

Unless a 242 was swapped in, the only year with factory full time was '86 4 cyl or 2.8 V6 with NP229.

 

the 242 was also available in comanches, it's just rarely seen

 

Gonna need some evidence of that... :cheers:

 

First, don't start that crap again.....

 

Second, you've been around long enough to know that anything is possible when you are talking about AMC-era Jeeps... :beerhead:

[JeepcoMJ]

I saw 3 comanches with 242's but know no history. it's not to say they weren't put in, but I've seen them. no factory support and no factual evidence of the option, as said AMC did just about anything a customer wanted...but, I can't back it with paperwork.

[CWLONGSHOT]

so what is the top speed 4wd should be used (not shifted just used)...231??

 

also don't let your rear tires spin while shifting into 4,your front and rear tires need to be turning at the same rate.

 

You are safe at any legal posted speed.

 

Personally, I limit my speed when in 4WD. (30-40MPH) If I feel I need 4WD, the weather conditions are pretty bad. Why compound that by driving too fast for road conditions. But that's just me.

 

CW