NP205 32 spline fig8 to GM NV4500???

[aotte1]

Question on options for attaching a '05 GM NV4500 to a NP205 with 32 spline input and short stick out, fig8. The NP205 is from a 1981, 1 ton with turbo 400 transmission, it has the adapter attached with the 6 bolt input.

This all new to me, read a lot of post here by many for a while. Hoping to go with the 205 if not to hard/overall length vs a 208 ( have several from CUCVs) or 241. The round 6 bolt input 205 are $ 1,000 here not rebuilt. This is for a '72 K10 short bed with 3/4 ton 72 axles.

My research has come up with the following, interested in pros and cons of different options along with others for the NP205, not planing to use the original turbo400 adapter.

1). Use a Northwest Fab Works 5/8 thick billet steel adapter between 205 and NV4500. Would use ORD dual shift. Is the NV4500 output shaft directly compatible - bolt up without changes needed? Is this ok without the trans/TC adapter with its support feet, additional support can done another way if needed. For example use a steel NV4500 tail adapter vs stock alu. one?

2). Use the stock steel turbo 400 adapter with longer NV4500 output shaft?

3). Use AA adapter kit for this application, at about $550, do not understand why you need the different tail shaft adapter?

4). Get a round 6 bolt case. Where to find?

Thanks,
Les

Note: if this question would be better placed as a follow-on to existing thread to help keep this subject better organized, e.g. Larry, Steve ..... please let me know. As I do not know the exiting threads on this.

[aotte1]

A couple of photos that show the NP205 and the original adapter to the turbo 400.

[obijuan]

In order to not notch the factory nv4500 tcase adapter I'd put a long input gear and the AA spacer with the nwf pattern adapter. No personal experience with that.

My personal experience is putting a 203 in between the two. Love it.

[franken]

The TH400 adaptor in the pics won't bolt to an NV4500. The best solution is to find a round pattern 205 from a mid-80s truck. They come up for sale on pirate once in a while. You might want to lurk in the GM fullsize area over there, where this has been done over and over.

I parted a truck to get a round 205 and traded my long input for a short one. I have a planetary doubler to go between...

I assume this is the one you mean:
http://www.northwestfab.com/GM-NP205...pter_p_18.html

I'd say get the NWF one, or the similar one from AA depending on price 50-206.

[aotte1]

Franken,

Thanks, My initial thinking is to not use the original turbo 400 adapter currently on the 205 in the above photos. Looking into what it will take to use the Northwest Fab Works adapter, described more above. Yes, the AA kit you referenced is the one. Also the NFW adapter is the one you provide the link too. Continuing to look for the 205 with the round 6 bolt imput.

Thanks for recommendation to use the NFW adapter. Will continue to study this option. Still want to confirm that it's 5/8 thickness does not effect the connection between the trans output shaft and 205 short input ( not enough contact, does not slide in far enough).

Will read up at pirate too.

Obijuan,

Thanks for the information, hoping to keep everything shorted in total length. The NFW will bolt this 205 and NV4500 together, with mods to the trans adapter?

Les

[franken]

Unbolt the TH400 adaptor and the bearing retainer under it. Bolt on the new adaptor after pressing the seal in. The tailshaft on the 4500 may need to be shortened. You can grab the AA conversion guide which has a reprint of an article doing this swap. That mates the trans and TC.

You need to grind on the 4500 tailhousing to clear the shift rail as mentioned above, and make or buy a mount for the shifter.

Next is a bellhousing. I seem to recall there was a bolt pattern change on the 4500, so there are a few bellhousings. Which is yours and what BH do you have?

Then there's the mechanical vs hydraulic clutch question.

[aotte1]

Fraken,

Thanks for the additional information on connecting the trans to TC.

On the Bell housing, still to be determined. Thinking of a mechanical, as that is what this truck has now. However, not opposed to hydraulic, have that on 1986 short stepper with LY6 overdrive four speed. First option is to use a 1968 to '72 SM465 cast iron bell housing. Know it needs to be modified a bunch, working on that now. Lower two hole, redrill one and the other TIG weld some and redrill. The upper two need more work, have TIG in more material. Couple of photos of bell housing planning and last one is the '86 with LY6.

[obijuan]

thats alot of work. i opted for advance adapters hydraulic bell housing.

[aotte1]

Can see where the hydraulic clutch is nice if the frame twist some in rough conditions.

[SunSoaked]

I got a brand NEW round pattern case and brand NEW 32 spline input for $150 from a pirate connection. He has a stock of them from a business buyout years ago. Bolts right up to the AA spacer ($80). Boom done!

[aotte1]

SunSoaked,

Thanks for the information on how you did yours.
Did you use the long or short 32 spline input shaft? Not knowledgeable enough on 205s, to know short or long from your photo.

Les

[obijuan]

He put up a pic of the outputs. But if you use the AA spacer then you use the long input. No spacer requires the short.

[SunSoaked]

obijuan is correct. Here's the input side with the AA spacer attached. I'll log into Pirate and get the guys username from my messages. It's been awhile and I don't recall off the top of my head. He had like 2 dozen cases/shafts. He had a business converting ambulances over to 4wd cuz I guess he lived out in the stix somewhere.

[SunSoaked]

His username on the Pirate site is gearedfather. You should be able to find him in the members list or do a search.

Mike

[aotte1]

Thanks for all the information and photos!
My current '81 205 has the short 32 spline input start.

Les

[snj8198]

Sorry aotte1, I'm just now catching your thread.

6 bolt t-cases are so stinking rare and the supply of remachined 6bolt pattern aftermarket empty cases have dried up. I got a 6 bolt empty case and stuffed my 205 gears into it along with a ORD 32 spline input gear. The case bolts directly to the tailshaft of my NV4500 short shaft.

I bought my NV4500 as a complete new package including bellhousing for mechanical clutch, trans, and empty round pattern t-case from GearTechHD who I think is out of Maryland IIRC. You can try contacting him but I know he was getting his empty cases from ORD which last i heard are out of them.

Knowing your search battle you may have to go with an AA adapter and use a coupler that fits your shaft lengths.

[aotte1]

Steve,

Thanks for information on your setup. Planning on similar one, to yours, I think. It will be a round six bolt case, with the guts from a '81 205 with 32 spline, short shaft input ( are you using the short shaft input). The NV4500 will be a GM '95 4x4. ( still researching exact specs for it. Which specific application it was used in). You mentioned your NV4500 is a short shaft output. Do all GM 4x4 4500s have the same tailshaft "short shaft" as yours. "Short shaft" means the shaft extending beyond the NV4500 rear adapter.

One other mod I need to make is replace the rear output slip joint. Is their a good reference here on doing this/ parts needed. Reason, this is going in a ' 72 short bed.

Note: The 32 spline '81 205 is from a 1 ton crew cab with turbo 400.

Les

[snj8198]

Pertaining to my "short shaft" statement, I may have misspoke. I do not remember if there are long and short shaft NV4500's. My apologies if garbled you up on that. For the transfer case I am not using an input shaft at all (male), I'm using an input gear (female).

What I did was when I swapped the guts from my '79 NP205 into the aftermarket 6 bolt case I installed a 32 spline input gear that replaced the input shaft of the t-case. This allowed me to slide and t-case directly onto the output shaft of the transmission and eliminate the coupler and any adapter. My t-case is bolted directly to the flange of the transmission tail shaft. This flange is machined to clear the t-case shift rails. This is the toughest combo you can get.

Here is a link to ORD's slip yoke eliminator kit (SYE).
http://www.offroaddesign.com/catalog...rcaseparts.htm

I don't know who else is making SYE kits for the 205 but this should get you started on your search at least.

During your search look into speedo gear options as that is mounted in the tail shaft and will need to be addressed based on whether you want to run mechanical or electrical.

[aotte1]

Steve,

Thank you again, no problem on the transmission output termanology. I have a contact at a national transmission rebuilding facility here, that has the specifics on the NV4500 variations by year and application. Even in the year I like, '95 there are several variations.

I miss spoke too, about the 1981 GM NP205 ( see note above for application) that I am starting with. The input on it is the, short 32 spline gear ( 1.5 to 2"), not a shaft. Knew it (shaft) was not a good description, however, from my reading of information had not seen it called a gear, the term gear makes much more sense. Thanks for pointing this out.

Do you think the original 205 input gear I have from the '81 one ton turbo 400 application is similar to the ORD kit you referenced?

Very good point, had not yet thought about mechanical speed-o-gear being in that Alu. tail shaft.
Need to get under the truck and do some angle degree reading on the drive shaft with the original '72 205, to see how much bind the U-joints will be in with the longer alu tail shaft. It is a short bed K10 with '72 3/4 ton axles added.

Thank,
Les

[snj8198]

Sounds like you know more than me about the different length variations offered through the years. Thanks for the leg work, I'll be riding your coat tails on that info.

Do you think the original 205 input gear I have from the '81 one ton turbo 400 application is similar to the ORD kit you referenced?

I don't know, it looks like they offer only two options, but i bet a quick call to Steve or James Watson at ORD would straighten a guy out pretty quick!

Need to get under the truck and do some angle degree reading on the drive shaft with the original '72 205, to see how much bind the U-joints will be in with the longer alu tail shaft. It is a short bed K10 with '72 3/4 ton axles added.

Sounds like a CV is in your future. Also, depending on any and how much lift, you may need to rotate your rear end too.

Just for kicks, are you planning to run rear disk brakes? If so, have you thought of an e-brake?

http://www.highangledriveline.com/e_brake.html

I ask because if so then now is the time to consider hanging a pinion brake off the tail of the T-case. Since you will need to be building drive shafts anyway, now would be the prime time to incorporate all of these parts to save money and remods down the road. I am currently learning this the hard way.

[aotte1]

Steve,

Thanks, for the good questions for me to think about on whole project.

Do not have an answer for rear disk brakes yet. It is a good question as the 3/4 ton drums are really heavy. The axles are '72 3/4 ton.

Les

[snj8198]

If i remember i believe the disk swap drops close to 100lbs per side, if you were worried about the weight savings.

['63GENIII]

Originally Posted by aotte1

Steve,

Thanks, for the good questions for me to think about on whole project.

Do not have an answer for rear disk brakes yet. It is a good question as the 3/4 ton drums are really heavy. The axles are '72 3/4 ton.

Les

Looking good there Les! Im just a bystander on this one. I cheaped out with the divorced set up. The married deal is a little too technical for me.
On the rear discs though, I went from a '73 D60 drum rear to an '05 14BFF from a '05 2500HD. TBH, I think it weighs more than the 60. Everything about the 14bolt is bigger and heavier except for the discs. If I had to guess, the 14 bolt is at least 100 lbs heavier than the old 60. BUT.... there's good news. The parking brake does work as intended and the truck does stop better than before (and quite arguably better than the Denali that we have). Stopping when towing , there's just no comparison to anything Ive driven. That seems to be where the disc rear really shines. Give the choice, I wouldn't do the discs unless you get a smoking deal on a rear axle that is set up with the right gears, discs AND a real factory parking brake. Otherwise, the big old drums worked great for years with a lot of abuse dispensed on them.

[snj8198]

I agree Gen three

[aotte1]

Chris,

Thanks for jumping in with your experience with the Dana 60 vs a newer 14 bolt.
Since this is a short bed '72 do not have plans to tow anything heavy. Steve thanks for your second on the good breaking capabilities of the drum Dana 60. What diameter where your rear drums, 11, 12, 13, along with width if you know. Mine are 12x2.5.

This Dana 60 has what seems tobe larger shoes/drums then the original GM '71 size, they are 12x2.5. Have not looked at them for several months, but remember them being 1/2 inch wider then specifications for '71. Previous thread discussed certain GMC / Chevy as having the 2.5 wide drums, and that specs could be wrong, in that original trucks have 2.5 wide shoes. Any information on what were the largest drum brakes for the Dana 60 with stock axle length SRW, what models have them. A thread by Larry on " 11 inch to 13 inch... " also talked about bigger rear brakes, I think his information was on Dana 60 too, not sure. And I will do some research too. May be move the brake discussion to a new thread to make it easier for others to find.


Thanks,
Les