NP247?

[juhap]

Can I put a NP247 behind my tf 998?

Does anyone know anything about this swap?

NP247 I´m talking about is form 1999 Grand Cherokee 4.7

[carnuck]

Splines in the tcase may be twisted or different spline count and the trans output is 1" short

[captspillane]

The 247 should work well, but as always you have to find someone who has already done it. My 247 is buried in a garage and will likely stay there for the next several years.

The 247 is drastically better than the 249 it replaced. The limited slip lasts much longer, reacts much faster, and doesn't have toxic out of production fluid in it like the Viscous Couplings in our Eagles and the 249.

[TheWraith]

According to Novak there were three different length input gears used in the np231, and these *should* interchange with the np247.  If nobody else has done the grunt work already, you might be able to figure out a bolt-up configuration (and document it here of course).

Looks like the np247 all came with 23 spline inputs if that helps.  NP231 came with either 23 or 21, so you could swap inputs if need be.

http://www.novak-adapt.com/knowledge/np_nvg_input_gears.htm

I know there is a thread on here where TCs were being discussed to some length, but I can't find it right now.  Anyone else remember seeing it??

[BenM]

You may need to swap the input, but it's possible. The NP/NV cases all have the same mounting patterns. You may have to modify the rear drive shaft to not collapse to use the slip-yoke or get an eliminator kit from a jeep store.

[captspillane]

Jeep CJ's used 21 splines and some of the older XJ's used 21 spline with their NP231, but as I understand it they phased all that out well before 1990. The vast majority of transfer cases out there are 23 spline along with our AMC Eagles. The TF998 has room and I'm confident it accepts all three input heights. I've heard of some combinations of Jeep transmissions not having room for the taller inputs, but never that problem with the stickshifts or automatics found in AMC Eagles.

All 249, 247, and 242 transfer cases have the same forward casting and are very closely related. Your XJ NP231 is totally different, with a different number of bolts holding the front and rear halfs together. The Eagle transfer cases actually have the 249/242/247 bolt pattern to the case halves and are obviously direct ancestors.

I bolted a 242 into my Eagle with the original driveshafts. I have information about that in my project thread, "Perkiomen Project Pics." Essentially you take the long front yoke off and put on the shorter Eagle yoke, which shares the same splines and bolts directly on. Then I put a slip yoke on the original Eagle Ujoint and a 3" piece of pipe inside the old slip yoke. I drove for years with no vibrations and it cost less than $40 to install, including the purchase of the 242.

[carnuck]

The 4 cyls kept 21 spline on everything except 3 speed automatics and late 90+ models with AW4. We put an AW4 with NP242 in SOTE with a custom trans crossbar and driveshafts from my pile of 30 or so spares. (from all kinds of vehicles)