Transfer Case Question for LS Swap

[Chris Laun]

I've been reading up recently on the LS swaps that a few of you have done into your alphas, and one common thing I've noticed is everyone seems to be more concerned with grenading the front diff than blowing up the transfer case. What are our stock transfer cases rated to power-wise? I'm planning on dropping a crate LS into my alpha in the next coming months, and as I plan on using my truck more in sand and snow than the rocks, I'm not exactly worried about the front diff as I'll be in wheel-slip situations. I'll also be having my trans upgraded and serviced to handle the increased power and torque of the LS. Have any of you made any upgrades to your TCase other than the metal shift fork? Or is it ready to roll? Thanks!

 

[4speedfunk]

Fresh clean fluid is the key. Periodic chain replacement is a good idea too. All (I mean ALL) of the t-case failures I've seen were do to neglect or some minor internal failure that led to a total inside-out explosion. A failure from shear brute power....is a Sasquatch. Lots of people swear they've seen it but in reality...there's usually another explanation.

Most of the time, they just quit working or you have binding issues....which if goes untreated will surely result in a "tooth salad" with extra gravy. The biggest complaint by far is the lack of a 2wd mode. I'm not aware of any specific mods to increase the strength of the stock t-case. If you want get stupid with the skinny pedal, most guys opt for a cast iron (gear driven) NP205.

Front diff?? Oh hell yeah. It's a complete turd in any form (alum, iron, or top secret unobtainium). If you plan to stomp a built V8 H3 from a dead stop with 35" tires...have another AAM-7 on the shelf. Outfitter Design is working on a Dana 44 replacement IFS but anything can be broken.

 

[Chris Laun]

Well its nice to hear that the TCase should hold up to more power! Its one less thing to worry about come swap-time. And that dana 44 sounds really interesting! Hopefully it will be out soon enough to swap in at the same time. But going back to the NP205 you mentioned, would you consider that as a good alternative to our stock TCase? Is there a benefit to having a gear driven case over a chain?

 

[USMC_TOP]

Gear on gear is stronger than gear and chain. In the day a ran a chain driven np 208 behind 550 hp BBC with 38 boggers and never broke it. Swapped it out once due to a clunk at take off but I never had one fail. I would trust what 4 speed is telling you and spend that replace the case money elsewhere......... you should be just fine.


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[4speedfunk]

I'm not a "t-case expert"...but, I hang with a bunch of Jeepers and full-size diesel guys. When I say diesel guys, I mean SERIOUS, nationally recognized, competition, pulling trucks. They are all Cummins freaks and they build some serious power. These guys destroy Dana 80s and Sterling axles like tinker-toys, and they spend money like no hobby I've ever seen!

I cannot imagine how they stay married! I can tell you what my wife would say if I came home every weekend and said... "Honey, I'm gonna need another $6k to get the truck to a full-pull". Yeah right. My clothes would be on the front lawn in five minutes!

Anyway, many of theses guys use the NP205, in various forms...chain or gear. The 205 is sort of a crude t-case by today's standards but, its cast iron and comes in both passenger and driver drop. This same crowd uses all sorts of adapters, and frankly I get confused because their rigs are basically FordChevyDodgeWhatever trucks...built from many different models. Obviously, these guys don't care about petty things like Vehicle Speed Sensors or Encoder Motors. Hell...they don't even care if it fits (they'll make it fit). So, its a different world when you start talking mods at this level. You might want to track down a forum member named MaxPF. He's knowledgeable enough to have a conversation with my diesel friends and actually understand what they are talking about.

As for the H3? Like most of the truck, a t-case swap is an "all or nothing" mod. If you want to keep the electronics functioning, then you're stuck with the BW 4493/4494 full-time case. If you want to replace it with something beefy, then you'll have to live with dash lights, no traction control, and levers coming up thru the floor in all sorts of locations. There is a guy on 355Nation (Colorad/Canyon forum) that installed a NP241 in his Colorado. Not sure its technically an "upgrade" from the stock BW case but, it does have a VSS and 2wd mode (with manual levers). My big hang-up with swapping out my 4494, is that I don't want to loose the 4:1 low range.

 

[Chris Laun]

Holy crap those are some big toys! And when it comes to our little TCase, I actually prefer the full-time 4wd, though the occasional doughnut with a big LS in 2wd mode would be fun... But for the sake of keeping the interior as stock and clean as possible, I think I'll be sticking with the stock case. I haven't had any issues with mine yet, but I think when its time for the engine swap, I might as well upgrade to the 4:1 case with the metal fork

 

[06 H3]

These H3 cases are stout IMO but if you wanted to make electronics work I think it will be pretty easy and here's why, people LS swap everything! All GM stuff uses VSS in the t case if it's 4wd and in the tailhousing if it's 2wd. Because of this most everyone has VSS adapters, retrofits, etc. then leave the encoder motor in and the only real problem is mounting a shifter. That's the one thing that's tough, adapting it to electric shift.

http://www.pirate4x4.com/forum/chevy/770136-how-do-i-put-vss-sm465-np205.html

People put reluctor rings on the end of the shaft and a sensor.

Atlas have VSS adapters as an option when they build your tcase.

NP241 has a factory VSS that will work too

 

[atvspeed4]

These H3 cases are stout IMO but if you wanted to make electronics work I think it will be pretty easy and here's why, people LS swap everything! All GM stuff uses VSS in the t case if it's 4wd and in the tailhousing if it's 2wd. Because of this most everyone has VSS adapters, retrofits, etc. then leave the encoder motor in and the only real problem is mounting a shifter. That's the one thing that's tough, adapting it to electric shift.

http://www.pirate4x4.com/forum/chevy/770136-how-do-i-put-vss-sm465-np205.html

People put reluctor rings on the end of the shaft and a sensor.

Atlas have VSS adapters as an option when they build your tcase.

NP241 has a factory VSS that will work too

We have everything on the bench to install a cable shifted 241 and keep the electronics working + keep console looking stock. Just need time which is in short supply the past few months.

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[06 H3]

We have everything on the bench to install a cable shifted 241 and keep the electronics working + keep console looking stock. Just need time which is in short supply the past few months.

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Can a 4:1 gearset be put in a 241? They are similar to a 231.

 

[atvspeed4]

Can a 4:1 gearset be put in a 241? They are similar to a 231.

Unfortunately the only company that made a short run of the parts for a 4:1 conversion for the 241 is long gone. This tcase is just temporary we will be building a Dana 300 with 4:1 and machining the new parts for that to adapt to electronics

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[4speedfunk]

I ran into a an XJ guy at the badlands that was running a Dana 300/241 doubler case. It used the front half of one and the rear half of the other. Crazy low range but still very streetable. I guess there are kits available to do stuff like this.
Frankly I would rather convert the stock BW4494 to have a 2Hi instead of 4Hi-street. This would bypass all the external fitment issues. Things like driveshafts, levers, holes in the floor, and electronic connections all stay the same. Plus you get to keep the factory 4:1 low.
The key is replacing the variable sun/planet gear with something fixed and only connected to the rear output. This would allow the front output to be disconnected entirely. Then just unlock the Warn hubs and you got 2wd.

It's always simpler on the forums!


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[06 H3]

Check out pirate for whacky setups, people take all sorts of whacky t cases and make doublers. I've seen Ford Explorer t cases, guys make a t case with a 1.4:1 high range because they make 60 horsepower and already have the lowest gear ratio in the diffs and need more gearing to move done the road. Then your typical 203/205, yota cases etc. but you will find t cases you never heard of being made for doubler use.

Most of these guys are machinists with badass machinery in their backyard barn or are machinists that work for a company that has 2 million dollar machinist equipment and make stuff on lunch breaks and after work.

 

[fanugy]

We have everything on the bench to install a cable shifted 241 and keep the electronics working + keep console looking stock. Just need time which is in short supply the past few months.

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Do you have a photo of the linkage and where you mounted in cab?


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