Got my NP3550.. now, which Diff?

[clarkerussell]

Hello all,

 

I am the proud owner of an NV3550 that will soon be replacing the BA10 that bit the dust in my 1988 4x2 4.0 Comanche...

 

I am also converting to 4x4 and have the option of buying the NV231 that was attached to the transmission, or I can upgrade to a 242 from a 1998 Grand Cherokee for $100 more... I have always wanted the 242, but I'm worried about it actually fitting the other components that I have.

 

So:

1) will it bolt up to the 3550? (Spline count is the same, what about shaft length?)

 

2) will the stock drive shaft/ft axle from my donor 1988 comanche match up with the 242?

 

Thanks.

[Oizarod115]

if the 242 from the grand is the one iwth the viscous coupling i say don't run it.

 

if its the normal style that was offered in XJs id go for it... i've heard the VC ones are weak

 

 

and yeah, we swapped from 242 to 231 on my brothers XJ and the D/S worked fine. same style u-joints

[clarkerussell]

if the 242 from the grand is the one iwth the viscous coupling i say don't run it.

 

if its the normal style that was offered in XJs id go for it... i've heard the VC ones are weak

 

 

and yeah, we swapped from 242 to 231 on my brothers XJ and the D/S worked fine. same style u-joints

 

How do I tell if it's the VC one?

[Oizarod115]

if the 242 from the grand is the one iwth the viscous coupling i say don't run it.

 

if its the normal style that was offered in XJs id go for it... i've heard the VC ones are weak

 

 

and yeah, we swapped from 242 to 231 on my brothers XJ and the D/S worked fine. same style u-joints

 

How do I tell if it's the VC one?

 

i think that one is the 249 but I'm not sure. someone else probly knows for sure... but of course it was offered behind a v8 so it can't be that bad :dunno:

[87manche]

if the 242 from the grand is the one iwth the viscous coupling i say don't run it.

 

if its the normal style that was offered in XJs id go for it... i've heard the VC ones are weak

 

 

and yeah, we swapped from 242 to 231 on my brothers XJ and the D/S worked fine. same style u-joints

 

How do I tell if it's the VC one?

 

i think that one is the 249 but I'm not sure. someone else probly knows for sure... but of course it was offered behind a v8 so it can't be that bad :dunno:

the grand cherokee one is indeed a 249. I don't believe it has a fully locked low range, hence the suckage. That and the viscous coupling is about $200 to replace when it goes bad.

The 231 and 242 are virtually the same dimensions.

if you're using your original driveshaft in the rear it will need cut down. If you have a donor 4x4 MJ it may work, I'm not sure how the length of the 3550 compares to the AX-15/BA10.

[Oizarod115]

the grand cherokee one is indeed a 249. I don't believe it has a fully locked low range, hence the suckage. That and the viscous coupling is about $200 to replace when it goes bad.

The 231 and 242 are virtually the same dimensions.

if you're using your original driveshaft in the rear it will need cut down. If you have a donor 4x4 MJ it may work, I'm not sure how the length of the 3550 compares to the AX-15/BA10.

 

all 3 tranny's have less than a 1" difference in length between them so the rear shaft from a similarly equipped MJ should work.

[87manche]

the grand cherokee one is indeed a 249. I don't believe it has a fully locked low range, hence the suckage. That and the viscous coupling is about $200 to replace when it goes bad.

The 231 and 242 are virtually the same dimensions.

if you're using your original driveshaft in the rear it will need cut down. If you have a donor 4x4 MJ it may work, I'm not sure how the length of the 3550 compares to the AX-15/BA10.

 

all 3 tranny's have less than a 1" difference in length between them so the rear shaft from a similarly equipped MJ should work.

very good then.

 

Also, pay attention to the input shaft when you get a t-case. lot's of variations through the years. If you don't get the right one you'll need a new input gear.