I just finished installing a new NV 5600 and a NP 271 transfer case into my 99 one ton . Everything fit nicely and I already had the wide crossmember to accept the 5600. Problem is that now my new front driveshaft rubs the crossmember since the output shaft of the transfer case sits so far back . What kind of front driveshaft do the 03's and up have is it smaller in diamater or do they have a modefied crossmember? Also is there a different vacume switch available for the transfer case with a longer throw to make my 4wd work right or do i just have to get the posi lock cable thing?

 

Add a drop-section to that area to clear the driveshaft, similar to the '89-'91 GM 4wd member.

Jack the front of the truck, such that the axle will hang to it's lowest point, use a tape measure from the pinion flange to the xfer case flange to determine the drop dimension

 

That is what I was gonna do I just wanted to make sure. I have never seen anyone else have this problem and was wondering what the 03's and up did with this transfer case and tranny combo.

 

I could be wrong here, but I think that the 03s and up are not using the 5600 6spd. It's some other 6spd that begins with a Z I think. So chances are that it's a completely different set up than the one you are using or trying to achieve.

 

third gens have the NV5600 also. The G56 came out in the 05s.

 

The 5600 came in some '99 trucks and the much larger 271 came in the '05 trucks, so there will be no oem parts to fit your configuration - yer gonna hafta punt......

 

Thats what I was afraid of. I'm gonna go to the driveshaft place this week and see if they can modify my front driveshaft to work if not i'm going to have to notch and gussit the crossmember but I was really trying to avoid this.

 

Don't forget to drop the front axle to it's lowest bump stop when you're checking for clearances.

Suggestion -

Cut the across member close as possible to the area that bolts to the frame, weld in a suitable piece of 1/4" plate to the correct drop dimension.

Cut the member about 6" over from the first cut, weld another piece of 1/4" plate there to the same drop dimension.

Weld the removed piece between the plates to achieve your drop section - still retains some of the factory look.

Look even better if you had a spare cross member to drop and section in.

Easiest, IMO, of course..................

 

Is the 271 "clockable"? Meaning can you rotate it one bolt hole to gain some clearance?

Does your 99 stock front shaft have a CV joint on the transfer case end? If not, that would make a difference also. My 02 would be able to run a front shaft without a CV on the case end, would hit the cross member.

Just throwing ideas out.

Jeff

 

Just finished the install of an 02 NV5600 and NP271 into my 98 12-valver. I used the front driveshaft out of the same, no problems. The crossmember was the same, just used rear holes. The skid plate was longer and rear crossmember was wider and required some extra holes in the frame. The rear driveshaft fit perfectly. The front required the yoke off the 02 dana 60 as the U-joint caps were slightly smaller on the front. I didn't do a side by side so I'm not sure of the diameter. Mine was strictly a swap, no fabrication work so maybe you just need to swap something else. I'd try to find someone with a comparable six speed truck to look at in person, maybe then the problem will be obvious.

 

Are you sure that was a NP271 you pulled out of the '02?

I thought they were NP241HDs.

I could be wrong .

............Jim

 

My mistake, I think your right. I've never seen the NV5600 with the 271, guess thats why it doesnt work.

 

The 5600 not only kicks the t\c back another 5", but the 271 is ~5" wider than the 241 between the mainshaft and the front drive, center-to-center - requires the drop-section for the front driveshaft.

And, the front drive flange is aout 3" further forward than the 241.

Ain't no hill, for a stepper............