NSG 370 Transmission

[Zorm]

Found one of these NSG 370 Transmission locally. If it has the right bell, it will mate up to my 4.7 stroker I6 in the 83. Has anyone got info on swapping in these trannys? Wonder if I can mate my NP208 up to it?

[Herk]

Expensive to fix if you break it.

[Stuka]

I have one in my JK. I assume this one is from a TJ? The JK ones will not bolt up to an AMC engine, wrong bell pattern. Only the TJ ones will, and the bell is integrated, not changeable. Over all I really like the transmission, and would love one in my J10. The only down sides are that second gear can be hard to shift into when cold (like freezing and below). Its a common issue. The second issue is they require special fluid, and there is only two options. Either the Mopar OEM stuff, or a Royal Purple one that is safe to use.

If you are going to swap in the trans, I would find an NV241 to go behind it. Very common, parts are readily available, and is a superior design to a 208. You will most likely need new drive shafts anyway because of the transmission change out.

As for swapping, you may need to do some cross member work. You will need to convert over to a hydraulic clutch setup. And the hole in the transmission hump may need to be moved back some.

As for repair costs, the only downside for you is the TJ one is somewhat rare. But if the guts are the same as the JK version, parts should be extremely common.

[wagon4wd]

depending how crazy you went with your stroker, the NSG370 isn't likely to be happy with the combination of the increased power of the stroker and the increased weight of a full size jeep. Chrysler rated the NSG370 for 272 ft-lbs of torque, and really only put them in wranglers and liberties, none of which come close to the weight of an SJ.

If you're planning on wheeling it and have big tires, I'd be looking at other transmission options myself. The NV3500 was rated at 300 ft-lbs which has a bit more of a cushion, then there's bigger truck transmissions which will certainly work better off road. Don't underestimate the power these strokers make down low, it's a mistake I made in a much lighter vehicle recently If you're not planning on wheeling it much, I could see why you'd want the nicer shifting NSG over the NV3500 (or even the NV4500).

To answer your question about fitment, though, the jeep 208 and the NV241 were the same input splines, diameter, and pattern, so it should bolt up as long as the input splines are the same. The NV3500 will use the same pattern as well. If you wanted to keep mechanical linkage, advance adapters sells NV3500 kits to the early bronco crowd that keeps the mechanical linkage.

[Zorm]

well, so maybe keeping the T176 with the NP208 is ok, I already did the crank position sensor mod to the bell, just thought a 5/6 speed would be cool to have.

[Stuka]

depending how crazy you went with your stroker, the NSG370 isn't likely to be happy with the combination of the increased power of the stroker and the increased weight of a full size jeep. Chrysler rated the NSG370 for 272 ft-lbs of torque, and really only put them in wranglers and liberties, none of which come close to the weight of an SJ.

If you're planning on wheeling it and have big tires, I'd be looking at other transmission options myself. The NV3500 was rated at 300 ft-lbs which has a bit more of a cushion, then there's bigger truck transmissions which will certainly work better off road. Don't underestimate the power these strokers make down low, it's a mistake I made in a much lighter vehicle recently If you're not planning on wheeling it much, I could see why you'd want the nicer shifting NSG over the NV3500 (or even the NV4500).

To answer your question about fitment, though, the jeep 208 and the NV241 were the same input splines, diameter, and pattern, so it should bolt up as long as the input splines are the same. The NV3500 will use the same pattern as well. If you wanted to keep mechanical linkage, advance adapters sells NV3500 kits to the early bronco crowd that keeps the mechanical linkage.

A stock JK Unlimited Rubicon weighs almost exactly what a fully loaded Grand Wagoneer (heaviest FSJ) weighs. JK is 4,340 and Waggy is 4,377. And they put the NSG370 behind the Pentastar V6 which has 285hp and 260lb ft of torque, more than that stroker is going to make unless its really tuned well with a biggish cam.

Having seen the gears/internals of both before, I would rate the NSG370 to be stronger than a T176. Not to mention a better overall design, WAY better shifting, and an over drive.

I also know several people with 6000lb+ JK's running 40's with the NSG, and none of them have broken the transmission. T-cases yes, but not the trans.

If it was me, and it was a daily driver that was geared correctly, I would not hesitate to use the NSG. And by geared correctly I mean not under geared. Transmissions in general hate when the vehicle has 33" tires and 3.31 gears or the like.

[rocklaurence]

I've put a AX15 in a FSJ and its great. I also provide a spacer ring to install the earlier NP208s. However, I'd pass on the 370 as its rare. THe AX15 is a better option ad the money you'll save on the 370 is small in comparison to the expense of adding a 5 speed.

[Herk]

The NSG 370 is not a particularly rare transmission, it's been the only manual transmission available in Jeeps for 10 years now and they make more every day. The 4.0L version was 2005-2006 only, so they are a bit harder to find, perhaps.

The 370 is strong enough, certainly stronger than an AX15 and comparable to NV3550. They got a reputation for being fragile early on mostly because a batch made it out of Toledo with no oil in them. Hardly the fault of the design. IIRC there may have been a TSB and updated parts regarding the reverse linkage on some early units. Something that's easy enough to address before it's installed.

Because it's a recent/current production unit, there's not a lot of aftermarket parts support. So expect to pay full Mopar prices at the dealer for parts. Probably not a factor if you score a good low mile box, but expect to drop $1000 to rebuild one that's worn out or has been abused. They like to have their oil changed fairly frequently.

The NSG 370 in my DD 05 Rubi has over 135K on it and is doing just fine. Not as quiet as it once was, but it doesn't seem to be getting noisier very fast either.

As for transfer cases, there are plenty of stronger and/or more sophisticated NP pattern units out there that should bolt up. I'd go looking for a 241 series.