Anyone with a NP242 and manual trans?

[OldSch88L]

I finally received my Novak 4x4 cable shifter to complete my 4x4 conversion. My setup is AX5, NP242 with a '96 build date, external slip yoke, Dana 44 rear axle, and Dana 30 CAD front with CAD permanently engaged. I did a test drive with the full time AWD engaged and noticed it was quite "lurchy" on low speed tight turns. Is that normal? I read that a little slack could be expected with a manual, that doesn't happen with an auto because the auto keeps a constant load. But from what I read,  I didn't expect it to be that bad... Could a stretched chain amplify this? If anyone did this swap, I'd really like their input!!!

[Pete M]

how did you mount to the late model 242 to the AX5?  far as I know, one is 21 spline, the other is 23.

 

is it the same sensation if it's in part time 4wd?

 

you should drop some of your trucks basic info into your signature.

[OldSch88L]

28 minutes ago, Pete M said:

how did you mount to the late model 242 to the AX5?  far as I know, one is 21 spline, the other is 23.

 

is it the same sensation if it's in part time 4wd?

 

you should drop some of your trucks basic info into your signature.

I did a 21 spline input shaft swap (long story short, it had late cut gears in it, so I found an early cut 231 and swapped its ring gear, planetary and 21 spline input shaft in the 242) and the part time does what is expected; ok in dirt, and pretty much impossible to do tight turns on pavement without the truck jerking, rocking side to side and chirping its tires.

[Pete M]

the 242 will start to bind in tight turns.  I'm betting that's what you're feeling. 

[gogmorgo]

A u-joint front axle might seem a little “lurchy” in tight corners. A ujoint doesn’t transfer rotation perfectly around a corner the way a CV joint does. The outer shaft ends up with an elliptical motion, so the wheels end up accelerating and decelerating within a rotation, even though the front differential is still driving them at a constant speed. The higher the operating angle of the joint (i.e. the tighter you turn) the more exaggerated the effect becomes. A driveshaft doesn’t really experience the same effect because the ujoints at either end cancel each other out.

 

The “slop” in a 242 people talk about is mostly down to having more driven parts, and the tiny amounts of lash between them add up. It’s not really any more a concern than the small amount of play every differential has.

I’ve also seen people talk about the 242 having a slight torque bias, which means it resists differences in axle shaft speeds, but I never found any real confirmation of that being true. 
 

What I will tell you is my MJ with a 242 and CV shafts is buttery smooth in full-time, and still a lot smoother in part-time than my 231 and u-jointed ZJ. Admittedly the MJ is an automatic and the ZJ is not, however I’ve got another vehicle with a full-time tcase and manual trans with CV axles, and it’s also buttery smooth in full-time, and again not anywhere near as noticeable that it’s in part-time as vehicles I’ve driven with u-joint axles. 

[OldSch88L]

10 hours ago, gogmorgo said:

A u-joint front axle might seem a little “lurchy” in tight corners. A ujoint doesn’t transfer rotation perfectly around a corner the way a CV joint does. The outer shaft ends up with an elliptical motion, so the wheels end up accelerating and decelerating within a rotation, even though the front differential is still driving them at a constant speed. The higher the operating angle of the joint (i.e. the tighter you turn) the more exaggerated the effect becomes. A driveshaft doesn’t really experience the same effect because the ujoints at either end cancel each other out.

 

The “slop” in a 242 people talk about is mostly down to having more driven parts, and the tiny amounts of lash between them add up. It’s not really any more a concern than the small amount of play every differential has.

I’ve also seen people talk about the 242 having a slight torque bias, which means it resists differences in axle shaft speeds, but I never found any real confirmation of that being true. 
 

What I will tell you is my MJ with a 242 and CV shafts is buttery smooth in full-time, and still a lot smoother in part-time than my 231 and u-jointed ZJ. Admittedly the MJ is an automatic and the ZJ is not, however I’ve got another vehicle with a full-time tcase and manual trans with CV axles, and it’s also buttery smooth in full-time, and again not anywhere near as noticeable that it’s in part-time as vehicles I’ve driven with u-joint axles. 

That's good to know! That's kinda how it feels like in tight turns; slightly accelerating and decelerating. In what year did those CV shaft came out on the D30?

[gogmorgo]

I don’t know if the MJ or XJ ever got CV shafts from the factory. Mine are just the cheap parts store ones that were sold as fitting my ‘91 MJ (and they do) but I’m pretty sure they’re intended as a ZJ shaft.