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Viper T56 or Richmond 6-Speed in a 4WD?

Discussion in 'The Garage' started by Greg72, Jun 22, 2005.

  1. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Has anyone ever seen a 4WD truck with either a T56 6-speed or a Richmond 6-speed mounted in front of an NP205?

    I noticed that the Richmond tranny uses a 1-3/8" 32-spline output shaft, so it kind of got me wondering if there's some slick way to mate one up cleanly to the input side of the 205 (also 32-spline)...without going to a longer, divorced setup???

    Mainly I'm interested because both offer a 50% overdrive in 6th....and that would really calm down my 7.56 axle gears (Mogs) for highway use.


    :usaflag:
     
  2. sled_dog

    sled_dog 1 ton status

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    I'm liking your thought process, I'd be interested for the close gear ratios(compared to a 465 anyway). Call AA maybe. Only issue I see is that this transmission is pretty long.
     
  3. big pappa b

    big pappa b 3/4 ton status

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    Yeah, real long and the shifter is all the way at the back. I still have access to my old a T-56 with a new clutch. Only had 18K on the car :thinking:
     
  4. diesel4me

    diesel4me 1 ton status Premium Member

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    Could be done...

    I have never actually seen one in a 4wd truck,but I have seen a few 2wd GM trucks with a Doug Nash 5 speed tranny before--(Doug Nash sold out to Richmond Gear I think?)...I dont see why it could not be done,other than perhaps the shifter being too far back...hooking one to a transfer case would not be that difficult,a home brew adapter might be all thats needed if the splines are the same as the input on a transfer case--or you could use a divorced case and a short shaft between the 2...

    When I had my 72 K5 years ago,and was discouraged with the SM465 tranny I put in it,due to the splined coupler and mainshaft woes,I came very close to buying an adapter from Advance Adapters to allow a M22 Muncie 4 spd to be installed to the TH350 style NP205 T-case...but I never persued it,I bought a few other K5's like it and never got around to doing it,and sold the 72.. :frown1:

    .I already had the tranny from a 69 Camaro,and I had no fear of it being strong enough,after seeing the thrashing they get with big blocks at the dragstrips!--.it would have been sweet to have a close ratio tranny that you could actually shift quickly in city driving,and not have to bog around in 3rd all the time,or wind out in 2nd gear...I havent been to Advance Adapters website in a long time,not sure what they might have for 'conversions" nowadays--probably all kinds of abortions available with all the new tranny's out there now!... :crazy:
     
  5. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Great idea.. Git er done and let me know what i will have to do. :cool1:
    I look foreward to drunken rambling about this 6 speed swap and monster big blocks at blazerfest. :thumb:
     
  6. k20

    k20 3/4 ton status

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    Yeh, just last night I was sittin here thinking about what Im gonna do if I break another th400. Im sick of it, its getting a manual next time. But, this truck may become a poser and Ill build another for full time playtoy, so I wouldnt care if I lost super low 1st gear, but would trade it for a close ratio tranny. Im watchin this thread for what gets said.
     
  7. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    A T56 is a monster of a transmission. It's like 32" from the front of the bellhousing to the end of the transmission body. There are specs somewhere.

    I think the Viper has a 30 spline output.

    A T56 is not something I'd put in a truck due to its 2.97:1 first gear (some only have 2.66:1). Double overdrive is nice... but let's say you do get that 2.97:1 first gear. 2.97*1.96*7.56=44:1. My wheeling rig has 64:1 and is rather disappointing.

    I think the 93-97 LT1 version T56 has the 2.66 first gear. It uses a regular bellhousing though. Pretty sure it's 27 spline output.

    The 98+ LS1 version T56 uses a hydraulic throwout bearing. I don't remember what the first gear and spline count is. Seems like it's 31 or 32 spline.

    That's about all I've got... it's going to take a lot of research.
     
  8. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Factor in a 3.1:1 WMS 203 rangebox to your calcs (I didn't mention that in the original post) and the crawl is more like 122:1.....not stellar, but nothing to sneeze at either.

    With the Richmond box, there are 1st Gear clusters available down to 3.01:1 (and 4.41:1 if you are willing to only have a .76 OD gear, which I'm not)....so in that case the crawl is more like 138:1.

    For my 38" tires (and a rolling circumference of around 116") that equates very close to the magical 1"-of-forward-travel/RPM goal that was discussed at length a while back..... I think I could live with a 138:1 ratio especially considering my ratio now is about 35:1.


    More food for thought. :thinking:

    The overall lengths and location of the shifter are concerning me....and perhaps the maximum torque handling capabilities of the tranny.
     
  9. sled_dog

    sled_dog 1 ton status

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    Now here is the thing, there is a second shifter location on the case. At lest I think its a shifter location and not an access point, but it may well be an inspection/access panel. I know the T5 came in two forms, the S10 and Camaro versions. The camaro had the shifter at the end of the transmission(same as the T56) and the S10 had it in the middle(about where the access panel on the T56 is).
     

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