1999 4x4 2 Door Tahoe

[Dneel81]

I used JB conversions for mine. It was more $$ than that. I did the shorty version of the flange output on the rear of my NP241 (the manual lever on the floor) since i have a 2 door and it's such a short driveline anyway. I changed out from a NP243 (the push button one) and so I knew what I had. Mine was $460 with shipping I think. Again, not cheap but well made. I'm much less familiar with other manufacturers. the little silver dollar sized badge on the back side of your transfer case should have markings punched in it with NP2xx. it's either 246 (pushbutton with autotrac), 243 (Pushbutton) or 241 (manual shift). The bezel looks to be quite faded and out of focus in your picture so you'll need to look closer at that when you have time. As to what it will fit, I think the general rule is to switch from the pushbutton stuff to the manual case for #1 reliability and #2 availability of aftermarket (4x4 enthusiast support) parts.

I will mention (unsolicited, I realize) that until you figure out your output on the transfer case, I'd wait on your driveshaft work. the CV joint is not easily swapped out (to a flange or yoke should you go that way) so wait until you have your measurements and do the driveshaft last. My rear driveshaft was stock with the male piece of the slip yoke when I bought my truck. I bought it and immediately switched in a nv4500 and NP241 combo from a 1 ton truck and did a shackle flip to get rid of the driveline vibration I had because of the bad geometry in my rear driveline after the nv4500 went in. Because of said bad geometry, I moved to a CV slip yoke and it was about $375 for the CV install, modifying the slip yoke pieces, labor and balancing. After I got serious about improving the offroad capability of the truck, I then went to the SYE kit from JB conversions and my shaft was another $140 to re-balance after going from slip yoke to flat flange (to match my SYE kit). Of note, I did the same thing up front after my solid axle swap. I stole a front shaft out of a newer f350 (slip shaft with flange on the transfer case side of the shaft). Turned out the CV was badly rusted, needed new joints all around and balancing of course..$350 on top of the $75 junkyard pricetag on the shaft itself. Still cheaper than building from scratch but annoying nonetheless. Yes I did put a flange on the front of my NP241 (from JB also) case to match the flange on the front shaft and then used a 1350 1330 conversion joint to match my dana 44 upfront.

Lots of info you probably don't need or care about but I figure I'd put it out there incase anyone is following in our steps.

BTW NP8 is an NV246 I believe , the autotrac function (check because I'm not certain). Do you have an "auto" button on your 4x4 cluster?

 

[bunchz71]

I used JB conversions for mine. It was more $$ than that. I did the shorty version of the flange output on the rear of my NP241 (the manual lever on the floor) since i have a 2 door and it's such a short driveline anyway. I changed out from a NP243 (the push button one) and so I knew what I had. Mine was $460 with shipping I think. Again, not cheap but well made. I'm much less familiar with other manufacturers. the little silver dollar sized badge on the back side of your transfer case should have markings punched in it with NP2xx. it's either 246 (pushbutton with autotrac), 243 (Pushbutton) or 241 (manual shift). The bezel looks to be quite faded and out of focus in your picture so you'll need to look closer at that when you have time. As to what it will fit, I think the general rule is to switch from the pushbutton stuff to the manual case for #1 reliability and #2 availability of aftermarket (4x4 enthusiast support) parts.

I will mention (unsolicited, I realize) that until you figure out your output on the transfer case, I'd wait on your driveshaft work. the CV joint is not easily swapped out (to a flange or yoke should you go that way) so wait until you have your measurements and do the driveshaft last. My rear driveshaft was stock with the male piece of the slip yoke when I bought my truck. I bought it and immediately switched in a nv4500 and NP241 combo from a 1 ton truck and did a shackle flip to get rid of the driveline vibration I had because of the bad geometry in my rear driveline after the nv4500 went in. Because of said bad geometry, I moved to a CV slip yoke and it was about $375 for the CV install, modifying the slip yoke pieces, labor and balancing. After I got serious about improving the offroad capability of the truck, I then went to the SYE kit from JB conversions and my shaft was another $140 to re-balance after going from slip yoke to flat flange (to match my SYE kit). Of note, I did the same thing up front after my solid axle swap. I stole a front shaft out of a newer f350 (slip shaft with flange on the transfer case side of the shaft). Turned out the CV was badly rusted, needed new joints all around and balancing of course..$350 on top of the $75 junkyard pricetag on the shaft itself. Still cheaper than building from scratch but annoying nonetheless. Yes I did put a flange on the front of my NP241 (from JB also) case to match the flange on the front shaft and then used a 1350 1330 conversion joint to match my dana 44 upfront.

Lots of info you probably don't need or care about but I figure I'd put it out there incase anyone is following in our steps.

BTW NP8 is an NV246 I believe , the autotrac function (check because I'm not certain). Do you have an "auto" button on your 4x4 cluster?

Tag says 246 GM. AND YES TO auto button.

I used JB conversions for mine. It was more $$ than that. I did the shorty version of the flange output on the rear of my NP241 (the manual lever on the floor) since i have a 2 door and it's such a short driveline anyway. I changed out from a NP243 (the push button one) and so I knew what I had. Mine was $460 with shipping I think. Again, not cheap but well made. I'm much less familiar with other manufacturers. the little silver dollar sized badge on the back side of your transfer case should have markings punched in it with NP2xx. it's either 246 (pushbutton with autotrac), 243 (Pushbutton) or 241 (manual shift). The bezel looks to be quite faded and out of focus in your picture so you'll need to look closer at that when you have time. As to what it will fit, I think the general rule is to switch from the pushbutton stuff to the manual case for #1 reliability and #2 availability of aftermarket (4x4 enthusiast support) parts.

I will mention (unsolicited, I realize) that until you figure out your output on the transfer case, I'd wait on your driveshaft work. the CV joint is not easily swapped out (to a flange or yoke should you go that way) so wait until you have your measurements and do the driveshaft last. My rear driveshaft was stock with the male piece of the slip yoke when I bought my truck. I bought it and immediately switched in a nv4500 and NP241 combo from a 1 ton truck and did a shackle flip to get rid of the driveline vibration I had because of the bad geometry in my rear driveline after the nv4500 went in. Because of said bad geometry, I moved to a CV slip yoke and it was about $375 for the CV install, modifying the slip yoke pieces, labor and balancing. After I got serious about improving the offroad capability of the truck, I then went to the SYE kit from JB conversions and my shaft was another $140 to re-balance after going from slip yoke to flat flange (to match my SYE kit). Of note, I did the same thing up front after my solid axle swap. I stole a front shaft out of a newer f350 (slip shaft with flange on the transfer case side of the shaft). Turned out the CV was badly rusted, needed new joints all around and balancing of course..$350 on top of the $75 junkyard pricetag on the shaft itself. Still cheaper than building from scratch but annoying nonetheless. Yes I did put a flange on the front of my NP241 (from JB also) case to match the flange on the front shaft and then used a 1350 1330 conversion joint to match my dana 44 upfront.

Lots of info you probably don't need or care about but I figure I'd put it out there incase anyone is following in our steps.

BTW NP8 is an NV246 I believe , the autotrac function (check because I'm not certain). Do you have an "auto" button on your 4x4 cluster?

 

[bunchz71]

Just got off of the phone with Toms. They do not make a conversion kit for the 246 transfer case with auto pushbutton four-wheel-drive. I ended up going with the reverse slip yoke and 1310 U joints throughout. Since this will basically be a daily driver and not a river toy, I am sure I will be fine. Fingers crossed.

 

[Dneel81]

should be fine for a DD

 

[jerryjoe28]

I run mine (np 246 transfer) with just a slip yoke with no problem

 

[bunchz71]

OK Guys, Just a quick update of how my last week has gone and where I stand with everything. I received my shaft from TOM WOODS ($448). Put it on, and the vibrations is GONE!

So at this point, New Front Driveshaft (Upgraded from Rough Country with the 6' Lift, New 4.56 gears in front and rear, and new Tom Woods Driveshaft in rear. Still upon acceleration, even at low speeds, there is a whining noise. Before anyone asks, I had the gears installed professionally, I did not do them. The guy that did mine does it for a living and installs them daily, so I am very confident everything is correct. Upon acceleration you hear a high pitched whining sound, and as soon as you let off the accelerator, it goes completely quiet. The sound sounds centralized in either the front differential or.......... the transfer case. At this time I am leaning to the transfer case. I pulled the front driveshaft out and it litterally seems the noise got worse.

Here is my theory, please tell me if everyone thinks I am onto something here.

With my 3:73 gears, all the gears were in a constant bind due to bigger wheels and tires and everything being under a load and basically never free wheeling. Now that the 4:56 gears are in I am thinking that I have a transfer case with 180,000 miles on it, with a wear pattern that was wore into all gears, sprockets chains etc with 3:73 gears. Now that everything is now running with less torque due to the gear change, I feel now the transfer case is working less hard and things are basically operating under less load and the wear is what I am hearing during acceleration.

PLEASE NOTE: I did not ever hear the whining noise until the gears were changed from 3:73 to 4:56 gears.

Feedback Please.

TIA

 

[bunchz71]

lol so no one has ever had this issue ?

 

[bunchz71]

bump

 

[jerryjoe28]

lol never had this problem .... guess it is possible

 

[bunchz71]

OK, So I pulled the transfer case (GM246) and tore it mostly down at this point. When I originally purchased this vehicle, I changed all the fluids so I would start fresh with the maintenance etc. When I changed the transfer case fluid (when I first purchased the vehicle I put the Valvoline Transfer Case Fluid in it(from Autozone). The bottle says that it is for the Auto Trak II transfer cases. When I drained the fluid, the fluid smelled burned and almost smelled like 90W gear oil. I put the Valvoline in it from Autozone, which is red in color. I have the complete rebuild kit on its way to change the transfer case oil pump, upgraded housing, bearings, clutch kit, and also the gears and chain. Chain seems very loose when I tore it down. It could possibly be ok, but wasnt taking any chances. Has anyone ever ran this fluid from Autozone ? Although it says its for the AutoTrak II, I am having my doubts.