Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Can I put a T56 behind a 6.2 in a 2wd Pickup or Sub?

Discussion in 'The Garage' started by OffRoad, Oct 8, 2006.

  1. OffRoad

    OffRoad 1/2 ton status

    Joined:
    Dec 8, 2002
    Posts:
    852
    Likes Received:
    0
    Location:
    New Brunswick, Canada
    I always this would be the ticket to high fuel mileage, and fun driving.:laugh:

    With the double overdrive (0.70 and 0.50) the RPMs would be low on the highway. With a 4.10 rearend and 31s, it could make up for not having the low first gear in a 465. Plus it would be easier and quicker to shift than a 465.

    What does CK5 think?
     
  2. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    I think the cold has affected your brain :D :D :D


    Seriously probaly more trouble than its worth. making the adapter would be a Nightmare and those things are pretty darn expensive an NV4500 or NV5600 would probaly be a better ,cheaper,stronger choice :D
     
  3. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    But if you do it take plenty of pictures!!!!
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,368
    Location:
    E-town baby!
    I don't see any problem with that...sounds like an awesome swap IMO. In a 2WD and behind a 6.2 that tranny should do just fine too. 1550 rpm at 70 mph would make for some wicked fuel mileage too.

    Hell, 4.56's would also be awesome...1750 rpm at 70 mph.

    Rene
     
  5. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    I just re-read the post 2wd i say go for it !!!!
     
  6. OffRoad

    OffRoad 1/2 ton status

    Joined:
    Dec 8, 2002
    Posts:
    852
    Likes Received:
    0
    Location:
    New Brunswick, Canada
    oh sorry yellowk20, i guess i wasn't clear about that. this would be for a 2WD truck, not 4WD. i'm not ready to start messing with divorced transfer cases yet.:haha:

    my highway RPMs would be stupid low.

    project idea -- i could run 5.13s in a hotrod. it would top out at 80mph, but it would be a rocketship getting there.:eek1:
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,368
    Location:
    E-town baby!
    Even with 5.13's it'd do 100 mph (theoretically) at 2700 rpm in 6th with 31's...the 6.2 is governed to 3600 rpm.

    Honestly I'd think with that tranny 4.10's are going to be too high...or you could drop down to a 27" tire and lower the truck some.

    Rene
     
  8. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,

    You were clear I just had a dumbass attack :doah:
     
  9. bowtiepower00

    bowtiepower00 1/2 ton status

    Joined:
    May 11, 2000
    Posts:
    924
    Likes Received:
    0
    Location:
    AZ
    The T56 would have to be seriously built to handle all of that diesel torque and weight. That would cost serious money. I think you'd be better off with a NV4500 (or similar truck tranny) and some 3.21 or 3.08 gears. I'd like to see a 6.2 or 4BT/ NV4500 setup in a 2wd sub or truck for a parts hauler/ DD.
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,368
    Location:
    E-town baby!
    i doubt the tranny cares about the weight, and to be honest the 6.2 doesn't make near enough power to worry that tranny. The T56 is probably stronger than a 700R-4 and those were the default tranny behind 6.2's for almost all K5's. I don't think this would be for towing, more of a cruiser, mpg king.

    Rene
     
  11. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    Rene is right that tranny is more than cabable of taking the abuse theres guys putting 500 plus hp through them in 3500 pound cars with no issues i think his slightly heaver halfton pickup and anemic 6.2 would be a piece of cakefor that tranny
    FYI the Corvette version is the only one with double Overdrive......maybe the Viper version also but I'm not sure about it. the Camaro/Firebird version is a single overdrive trans
     
  12. ARAMP1

    ARAMP1 Aviator Extraordinaire

    Joined:
    Sep 1, 2005
    Posts:
    3,983
    Likes Received:
    55
    Location:
    Memphis, TN
    I haven't seen any 6.2 making the kind of power a viper or corvette does, so I'm guessing that it would handle the 6.2 just fine. I had always thought about putting a Richmond ROD 6 speed in my truck up to a divorced NP205.
     
  13. clstolten

    clstolten 1/2 ton status

    Joined:
    Sep 4, 2002
    Posts:
    356
    Likes Received:
    0
    The camaros and viper t-56's had double overdrive as well.
     
  14. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    I'm almost positive the Camaro/Firebird's had overdrive in 6th gear they have that "skip shift" also
     
  15. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
  16. 79k20350

    79k20350 3/4 ton status

    Joined:
    Nov 22, 2004
    Posts:
    7,757
    Likes Received:
    1
    Location:
    Ct
  17. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,368
    Location:
    E-town baby!
  18. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,602
    Likes Received:
    551
    Location:
    Wasilla AK,
    yeah google is great!! i just typed in t-56
     
  19. jdemaris

    jdemaris Registered Member

    Joined:
    Apr 10, 2001
    Posts:
    76
    Likes Received:
    0
    I suspect it wouldn't work very well with a stock 6.2. A New Process 833 was used OEM with 6.2s and works out well - and can usually be found cheap. It has a torque rating of 260 ft. lbs., 1st gear - 3.09. 2nd gear - 1.67, 3rd gear - 1, and fourth OD - .73. Any overdrive above that would be kind of a waste of time - there's not enough power -and NA diesels have very limited power-bands.
    I've got many 6.2 powered vehicles - including four K5 Blazers, two 3/4 Suburbans, and a couple of pickups. A K5 with a 6.2, stock 15" tires and a 700R4 can just barely maintain 65 MPH when uphill grades are encountered on the highway. Put 31" tires on the same vehicle and it's constantly shifting in and out of overdrive since it becomes somewhat underpowered with the larger diameter tires.
    Two of my Blazers have T400s and they work great - but turn a little high a highway speed - even with 3.08 axles. I have another 6.2 Blazer and a 1/2 4WD pickup that both have the New Process four-speed manual trans with a .73 overdrive and that works very nicely. My 83 K5 with 6.2 has 235/85-16" tires (31.7" diameter) and a 4.10 axles (14 bolt rear from a Suburban) - and it seems to be just the right combination. Turns around 2050 RPM at 65 MPH which is just the right power-range for a 6.2. If 31-10.50-15" tires were used, it would almost be the same - they are 1" smaller diameter than my 16"s. My 1/2 ton truck with the same overdrive NP833 has 3.08 axles. It gets great fuel mileage but 1st gear is pretty high. If it was 2WD, it could be rough getting started on a steep hill without slipping the clutch. But, since it's a 4WD, it's no problem since I just stick the transfer-case into low range when necessary - which is rare.
     
  20. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,368
    Location:
    E-town baby!
    T56 close ratio: 2.66/1.78/1.30/1.00/.74/.50

    The 6.2 has a narrowish powerband so IMO a close ratio tranny is gonna be a hell of a lot nicer to drive than either a SM 465, NV4500 or A-833. Yes, all three I just mentioned have a much deeper first gear which was why i said if it were me I'd run some 4.56's with 31's. Even with a 2.66 first it'd be easy to get going in first and in 6th a 1750 cruise rpm at 70 mph is well within the 6.2's sweet spot for mileage and ability to hold the gear. Get to a grade and drop down to 5th and 70 is 2500 rpm...perfect rpm to pull any grade you want.

    The only drawback would be more shifting, but with the T56 I don't think it'd be as big a deal as with any of the wide ratio truck tranny's. Short throw and smooth shifting...it'd probably be a lot of fun.

    Rene
     

Share This Page