Hi, do you guys offer a Magnum crawl box for a 2007 6 speed Allison? Internet says the trans has a 29 spline output shaft. Could you reuse the planetaries I have in the current tcase (NP263XHD) ?
Last edited:
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Magnum for Allison?
- Thread starter GreenieK30
- Start date
We have a Magnum underdrive for the Allison specifically 
I wonder if this would be a better option for adapting an np205 to an Ally???
Always.
Hahahahahaha only problem would be the 5.33:1 lo/Lo would eat every drive line component behind the 8.1L!
Surprisingly, with all the research I've done for adapting my ally/np205 nobody has mentioned this as a viable alternative... Maybe for the above mentioned potential issues
Yeah, while the Magnim is super cool, using something like a 241 is probably a better combination than a 205.
Behind an ate point one the planetary is surely not a necessity but crawling while pulling a house down sounds fun! Just not putting Molly axles etc in a Dana70 if they're even available
I have a 205, plus I'm not sure if a 241 is any easier to adapt to an Ally 5spd?
Im building a rig with a pro rock 80 front, ouverson outers and Dana 135 rear. Probably have to put 40 spline shafts in the 205.
Edit: 34 spline http://www.northwestfab.com/Titan-Series-NP205-HD-Front-Output-Kit_p_2699.html
Edit: 34 spline http://www.northwestfab.com/Titan-Series-NP205-HD-Front-Output-Kit_p_2699.html
Last edited:
its only money just do it .
i have 2 ord doubler kits my self . . . . have yet to play with one . but 1 is going in the truck to be done real soon so will see .
i have 2 ord doubler kits my self . . . . have yet to play with one . but 1 is going in the truck to be done real soon so will see .
My current truck has a vortec 454 on propane with a th475, 2.72 Klune and Np205, ratio selection is great. Next rig in the works will be similar just more of everything lol.
Sounds stout! I'd be putting the magnum on my tow rig that's why the super low isn't really necessary but I'm already lookin at over 1k just in adapters so a magnum isn't far off to accomplish the same conversion
Someone used to make a 32 spline Allison output so a 32 spline female np205 would bolt up. Some guys use a Ford 205 with a 29 to 31 spline coupler shaft. Another option is a Dodge male 29 spline 205 input with the 29 spline sleeve. Or a Magnum. Or a 2wd trans and divorced 205. For an Offroad vehicle the Magnum seems to be the best option.
Yea I'm working on what will work, with this trans I have found the adapters but I will have to rebuild the 205 with the other input shaft and it's still expensive so if I could just bolt up a magnum well it may be worth the extra money
We have a Magnum underdrive for the Allison specifically
Can you guys use my tcase for the planetaries? Truck only has about 30,000 miles on it. Can you just send me the billet housing and I can assemble it or I can send you the front case parts? Should I call and bug Stephen?
Would a Ford or Chev 205 case work better for front driveline clearance on the Allison 1000? I have almost every np205 variant in my storage shed lol. Vehicle will be sort of low so not a real steep driveline angle. I can also do a 2 piece front driveline if clearance is an issue. Front axle has no tubes yet so offset is wide open.
The Magnum gets all new gear parts when it leaves here, we don't have an option to press the ring gear in yourself and in your case you can probably get decent money out of a good 263.
Also keep in mind that low gears aren't only about multiplying torque, they also drop your travel speed and give you more control in tight situations. Even the mighty Cummins can only idle so slow and travel speeds that actually qualify as crawling will require a good bit of clutch slipping or torque convertor slip/heat.
Also keep in mind that low gears aren't only about multiplying torque, they also drop your travel speed and give you more control in tight situations. Even the mighty Cummins can only idle so slow and travel speeds that actually qualify as crawling will require a good bit of clutch slipping or torque convertor slip/heat.
How many Allison Magnums have you guys sold? That platform seems new and not real popular yet. Preference on driver vs. Passenger drop? Only downside I see is 2 oil filters on the driver side, tossing a driveline could be messy. Both will be 1480 size so hopefully that issue won't present itself. Thoughts?
Just fill in a little more here, we often call the Magnum our "adapter with benefits" since a lot of the time you can spend a substantial portion of the Magnum price just adapting a 205 to the trans by itself and the Magnum bolts up with no adapter pieces in many cases so it kind of becomes the adapter.
I don't have any great ideas that would make a left hand driveshaft better or worse than a right hand. Sometimes it can matter if your diff is going to be WAY up in the engine on full compression but it's hard to tell what's happening there till you try it. For example we have to run an extra short oil filter on my big block in Wally because the driveshaft would hit it. And the upper link arm tries to use the same space as the starter so it has to have a clearance bend in it.
Not sure how many Magnums are behind Allisons and there's not a great way to search it but given that the tailhousing is just a GM bolt pattern with a 29 spline output it really doesn't matter as far as bolting up is concerned. With an input gear swap that same gearbox will bolt up to any GM trans with the factory adapter past about 1980. Pretty handy system!
I don't have any great ideas that would make a left hand driveshaft better or worse than a right hand. Sometimes it can matter if your diff is going to be WAY up in the engine on full compression but it's hard to tell what's happening there till you try it. For example we have to run an extra short oil filter on my big block in Wally because the driveshaft would hit it. And the upper link arm tries to use the same space as the starter so it has to have a clearance bend in it.
Not sure how many Magnums are behind Allisons and there's not a great way to search it but given that the tailhousing is just a GM bolt pattern with a 29 spline output it really doesn't matter as far as bolting up is concerned. With an input gear swap that same gearbox will bolt up to any GM trans with the factory adapter past about 1980. Pretty handy system!
I'm on the hook for a couple weeks from now when I can afford the shifter with it. Pretty stoked!
