On the fly 4 wheel peel?

[Joopin]

1046501

I just bought a 91 wrangler with a 4.0 liter and a 5spd. My main qestion was about switching from 2wd to 4wd... can this be done "on the fly"? I know it can be done in the newer models but I'm not sure about the 91... And if I can shift on the fly, is it safe to assume it is up to 55mph like the others? I read somewhere that all YJs can be changed on the fly, but I don't want to just assume it is correct...

Question 2, I also recently was told that from the mid 80s to the mid 90s all jeep engines were built by Mercedes and thats why you see those years with so many miles... (like mine at 189k) is this true? if it is, how do these engines compare with other years? Any info on these questions would be greatly appriciated... I'm really loving this jeep thing so far! Thanks.

[addsig]

 

[UrbanJeep]

1046506

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>I just bought a 91 wrangler with a 4.0 liter and a 5spd. My main qestion was about switching from 2wd to 4wd... can this be done "on the fly"? I know it can be done in the newer models but I'm not sure about the 91... And if I can shift on the fly, is it safe to assume it is up to 55mph like the others? I read somewhere that all YJs can be changed on the fly, but I don't want to just assume it is correct...

Question 2, I also recently was told that from the mid 80s to the mid 90s all jeep engines were built by Mercedes and thats why you see those years with so many miles... (like mine at 189k) is this true? if it is, how do these engines compare with other years? Any info on these questions would be greatly appriciated... I'm really loving this jeep thing so far! Thanks.

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>





I believe you can switch on the fly as long as you keep it at a reasonable speed like below 55mph.. I used to have a 91 four banger and do it on the fly... Second question I am not a 100 percent sure but I thought AMC still made the motors up through 90's

[addsig]

 

[CTJeeper]

1046514

I have the same jeep... 91 4.0 5spd. in mine, ive tried shifting from 2 to 4wd all different ways, and you definetly can shift into and out of 4 High at any reasonable speed... i havent tried above.. say 20-25mph, but then again if your goin 55 i dont knwo why you need it. going into 4 Low is a different story. I found the best way to hit 4 Lo is to be in neutral traveling.. about 5-10 mph. As for the engine... i think our 4.0 is an AMC 242... thats all i can say to that though... i may be wrong[addsig]

 

[ecor]

1046519

You can shift into 4 high upto 45mph without hurting anything. 4 low should not be anymore then 5 mph. as for the motor... The 4.2L was designed by AMC and run for many years being put together by AMC. All of it's life it was know for being a very reliable motor. The 4.0L is the exact same motor just bored to a smaller bore. the 2.5L is the exact same motor but just literially has 2 less cylinders. The 4.0L and the 2.5L where chryslers way of bringing the old motor into the new regs of the government. Diamler does own chrylser and they own Mercedes but the two paths have never met.



Hope this helps



[addsig]

 

[UrbanJeep]

1046608

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>I have the same jeep... 91 4.0 5spd. in mine, ive tried shifting from 2 to 4wd all different ways, and you definetly can shift into and out of 4 High at any reasonable speed... i havent tried above.. say 20-25mph, but then again if your goin 55 i dont knwo why you need it. going into 4 Low is a different story. I found the best way to hit 4 Lo is to be in neutral traveling.. about 5-10 mph. As for the engine... i think our 4.0 is an AMC 242... thats all i can say to that though... i may be wrong</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>



i can say that a rear wheel drive car on a spotty freeway with snow is not a safe place unless you are fwd or 4wd[addsig]

 

[jeepthrills]

1046758

Ecor



They have met. My buddy just got a 2002 Dodge Ram and it has a mercedes engine and transmission in it.[addsig]

 

[CTJeeper]

1046767

Haha Urban you are correct... probably not safe, but what jeeper has fun doing something safe

Haha just kidding I usually play in the snow in parking lots

[addsig]

 

[83CJ7]

1046834

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE> The 4.0L is the exact same motor just bored to a smaller bore. the 2.5L is the exact same motor but just literially has 2 less cylinders.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>



This will help with some of that

but a 4.0L has a larger bore than than a 4.2, just a considerably shorter stroke. thats why you can drop a 4.2L crank in a 4.0L block, and get a 4.5L.

-keith[addsig]