Modern T-cases

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Cecil14
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Modern T-cases

Post by Cecil14 »

So what's everyone running for t-cases anymore? I'm looking at swapping my short tail D300 back to an NP208 (noise), but is there a better stock chain case available these days? A regular part time case is just fine with me, but I would like it to be lever shifted like the stock unit, no interest in vacuum or electronics there.


Thanks all,


aa
Last edited by Cecil14 on Wed May 03, 2017 6:32 am, edited 1 time in total.
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Stuka
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Re: Modern T-cases

Post by Stuka »

Some may require adapters. The best chain drive for swapping these days is a NV241 from a JK Wrangler. As I recall they are a 23 spline input, which matches some FSJ transmission options. There is also the 241OR which has a 4:1 low range. Both are mechanically shifted.

Note: I do recall one guy swapping one, but cannot recall what he had to do, if anything.
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will e
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Re: Modern T-cases

Post by will e »

I run an Atlas 4 speed. I love the flexibility but it can be a bit of a chore.

This is what I have 1.0:1 / 2.72:1 / 2.00:1 / 5.44:1

I love the flexibility. The 2.0 is great for washes and shelf roads, 2.72 is nice for when I need a little more torque and the 5.44 lets me get pretty much as low as I would want for my rig and the driving I do.

But I don't think you would get as much advantage out of the 4 speed TC. Looking at your sig your tranny has a nice low first gear and an OD.

When you wheel with an Atlas you 'work' at it. One example: If am in low (my case 2.0) and want to get to 2.72 I have to shift the main case out of low into high (two sticks) and then shift the planetary into low (2.72) which is a single stick. That's three shifts (actually 4). And they are done different. The main case you should be in Neutral and moving slowly and even then sometimes it is finicky (it can be shifted at a stop sometimes as well). The planetary requires you to be stopped and in Neutral. So, while rolling and in Neutral to go from 2 to 2.72:

1. shift front wheels out of Low and into neutral. (you can actually do this while moving and in drive if you are going pretty slow, also it is perfectly fine to drive like this as long as you want)
2. shfit rear wheels out of low and into high
3. shift front wheels into high
4. stop and then switch planetary into low.

This means you have to pay a bit of attention to what is a head of you. If the truck stops while you are shifting the main case it can be a bit of a 'fight' to get into gear. So I watch for declines where I can allow gravity to pull me along if the shift gets pickey.

That said, I really like mine. There was a learning curve for sure. I like being able to run in low ranges with just rear wheel power (fun for washes and such). I enjoy the control of 5.44 which with your granny gear tranny is kind of already there but via the transmission. If you can find an option that allows low range twin stick it sure is a blast.
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Re: Modern T-cases

Post by tedlovesjeeps71 »

If your running a non-flipped Dana 300 now, you have a passenger side front? That eliminates most of the new stuff from a modern rig. What's wrong with the Dana 300?? Plenty stout, compact, good low range, and near simple to use. You say it's loud? As in something is wrong with it loud or are you trying to get Cadillac comfort from an old Jeep?


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Re: Modern T-cases

Post by Cecil14 »

Thanks guys.

Not interested in the gear vs chain debate, been there done that. I know the differences, and a chain case is what I'm after. :)

I'm not building a wheeler or rock crawler, my truck is a truck. I drive it around on the highway a lot, tow with it, etc. Just looking for a good reliable modern case.

@tedlovesjeeps71: yes, I am currently passenger side drop. I have a nice fancy D44HD driver's drop axle ready to go in if I find a good driver's drop case. If not, I'll swap the outers from that onto my current front 44 and run as is for now.


aa
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Re: Modern T-cases

Post by derf »

Stuka wrote:Some may require adapters. The best chain drive for swapping these days is a NV241 from a JK Wrangler. As I recall they are a 23 spline input, which matches some FSJ transmission options. There is also the 241OR which has a 4:1 low range. Both are mechanically shifted.

Note: I do recall one guy swapping one, but cannot recall what he had to do, if anything.
The JK Wrangler eliminated the speedometer output in the t-case. Instead, the computer uses the ABS sensors to figure on-road speed. So if you use a JK (2007-present) transfer case you need to figure out how to get your speedometer to work. I don't know if anyone makes a bolt on solution for that or not.

For the OP:

A YJ (87-96?) or TJ (97?-06), XJ Cherokee (84-01), ZJ Grand Cherokee (93-98), and WJ Grand Cherokee (99-04) will come with either a 207 or 231 (the 231 replaced the 207 in the late 80's), which is weaker than what came on the full size Jeeps, but it has a speedo output. The TJ Rubicon will have the 241OR that is beefier and has the 4:1 low range but it will have the speedometer output. (However, Rubicon cases tend to sell faster than pizza at a weight watchers convention so finding one is not easy.) You can also find an NP242 (217 in early model XJs) in the XJ, ZJ, and WJ. That gives you an extra option of full time 4HI on top of part time 4HI. All of these cases will bolt up in place of a D300 with no adapters, assuming you find one that is 23 spline and not 21 spline. You'll have to rig up a shifter for the case. Any flag shifter from a full size Jeep should work but you may need to tweak the connections.

In full size trucks, the 241 replaced the 208 in the late 80's.. They're both in the same ballpark for strength but the 241 has some improvements that make it worth pursuing.

If you want a passenger drop 208/241 case, your best bet is an 80's GM pickup/K5 Blazer/Suburban. Starting in the late 80's GM started to switch over to a driver side drop. Pickups were first in like 1988 I believe. The K5 lasted as a passenger drop through 1991 I think. Not sure about Suburbans. After 91, all GM full size vehicles were driver drop 241s.

To swap in a GM 208/241 to a Jeep transmission you just need a transmission to t-case adapter (to get the correct clocking of the case) and either an input shaft for the t-case or an output shaft for the transmission. You can get those all day at Novak or Advance Adapters. Swapping the input shaft on the t-case is far easier than the tail shaft of a transmission. But if the case is good and you need to rebuild the transmission anyway, the tail shaft option may be preferable.
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Re: Modern T-cases

Post by Cecil14 »

Thanks Derf. At this point I think I'm looking for an NP241DHD. I've made a few calls around locally and a couple of the yards around here have cases for about $200. I need to make a couple stops now to see what things look like.


aa
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Re: Modern T-cases

Post by derf »

Cecil14 wrote:Thanks Derf. At this point I think I'm looking for an NP241DHD. I've made a few calls around locally and a couple of the yards around here have cases for about $200. I need to make a couple stops now to see what things look like.


aa
That works too. Good luck in finding what you want. :-bd

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Re: Modern T-cases

Post by will e »

Yeah an Atlas is not the right fit for your intentions.
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82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge
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Re: Modern T-cases

Post by Stuka »

Cecil14 wrote:Thanks Derf. At this point I think I'm looking for an NP241DHD. I've made a few calls around locally and a couple of the yards around here have cases for about $200. I need to make a couple stops now to see what things look like.


aa
Be aware that most of those will be electronically or vacuum shifted. The Wranglers do not use the HD. As i recall the only difference is the output shafts and some case webbing.
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Re: Modern T-cases

Post by Cecil14 »

The early 241s (to 1996 at least) were still mechanical, from what I can find. I'll know for sure when I can see one in person. It definitely needs mechanical shifting and a mechanical speedo.


aa
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Re: Modern T-cases

Post by tedlovesjeeps71 »

Cecil14 wrote:Thanks guys.

Not interested in the gear vs chain debate, been there done that. I know the differences, and a chain case is what I'm after. :)

I'm not building a wheeler or rock crawler, my truck is a truck. I drive it around on the highway a lot, tow with it, etc. Just looking for a good reliable modern case.

@tedlovesjeeps71: yes, I am currently passenger side drop. I have a nice fancy D44HD driver's drop axle ready to go in if I find a good driver's drop case. If not, I'll swap the outers from that onto my current front 44 and run as is for now.


aa
I hear ya and wasn't trying to start the debate. Lol. Sorry for that.
Two things that came to me while reading through are some other small hurdles. Many of the chain drive cases may be of a slip yoke design. You'll probably have to have a new rear driveshaft made anyway (and front?) Depending on length difference so it may be moot. Kinda depends on what you find. The drivers side drop swap may or may not be too hard to get the linkage to work. You could possibly keep the Jeep shifter in the same spot and use a cable to control it.?
My 89 suburban has a 241 I believe, I'd have to look to verify. Last suggestion is to check whatever you find for chain slack before plunking down the Benjamin's. Good luck and post what ya find. Image


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Re: Modern T-cases

Post by Cecil14 »

Not a problem at all. haha Just didn't want the old debate to start screaming again...that dead horse is pulp at this point.

I will definitely need new shafts, I'm going to a van D60 in the rear anyway, so that's already in the plans. As for the slip yoke, I rarely take my truck off pavement anymore so it's really not a big deal to me. I'll probably just have a driveshaft built that fits both ends once the hard parts are in place.

The shifter...I'll figure out once I get there. I'm sure it's gonna take some fab work one way or another.

I'll probably go through the case before I install it regardless. There are a few upgrades here and there for the Dodge cases, and I want to make sure everything else is in good order. It's a 20 year old case...it's definitely time for a refresh.


aa
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Re: Modern T-cases

Post by Stuka »

On a truck the slip yoke is really not an issue at all. Its only an issue on short wheel base vehicles like YJ's and TJ's.
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