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Transmissions

Discussion in 'Early CJ5 and CJ6 Tech' started by JK67CJ5TX, May 25, 2004.

  1. May 25, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    I have read much about transmission swaps, rebuilds and etc. here. I have also noticed that my T-86 is a little strange to my way of thinking and driving. Off road, I think it is plenty OK. On road first is normal, second is great, and third seems to be too big a step. Third gear doesn't really function good until about 45 mph. There is this huge gap from the end of second at about 35. Is this just the T-86? My jeep is basically stock with 3.73's and rear positrac and 31 " tires. What is the best all around transmission to replace this one with when it goes?

    John
     
  2. May 25, 2004
    66cj5

    66cj5 Jeep with no name

    NorthWest Indiana
    Joined:
    Sep 10, 2003
    Messages:
    2,069
    my t-14 has similar "issues" while trail riding, one gear is too low, the next is too high. Been thinking about an OD.
     
  3. May 25, 2004
    James P. Enderwies

    James P. Enderwies Sponsor

    Lake Havasu City, AZ
    Joined:
    Feb 2, 2003
    Messages:
    747
    Humm? My T86 works great......with 5.38's. :D

    Of course 60 mph is about it. Doing about 3500 rpm then. :shock:
     
  4. May 25, 2004
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,922
    Have you ever owned and drove a 3 speed manual before your Jeep, this is actually one of the drawbacks to a 3 speed manual, what you are experiencing is quite normal, you just need to rev your motor a little higher in 2nd before shifting into 3rd.
    If you put a tach on, you are probably shifting into 3rd gear while your motor is only revving about 1800-2000 rpm, try revving to about 2400-2600 rpm before shifting.
     
  5. May 26, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    Thanks guys. My previous 3 speeds were column shift sedans and their gearing was nicely progressive. I realize that the t-86 may be somewhat of a compromise. As I said before, offroad it is fine. It is just that on the road there seems a need for another gear between 2 and 3 to make driving smoother. I have fallen into the habit of revving the engine much higher to get a little farther into the rythm before shifting to 3. In some cases, I just drive around in 2, since it is very hilly around here. In eventually replacing the tranny, I am trying to anticipate a move to a 4 speed. My old, old, old Ford pickup had a nice four speed that had a compound low and 2-4 were good. In planning ahead, I am trying to get input on which of the four speeds will be the easiest to swap in and will give the better compromise for on and off raod use. Obviously the compound low is a plus for trail work, with 3.73's. That also works in fourth gear as well for easier high speed cruising.
     
  6. May 26, 2004
    blabhern

    blabhern New Member

    Joined:
    May 24, 2004
    Messages:
    6
    There is a writeup on installing an SM420 somewhere on this site. I've had a T18 jeep tranny in a CJ7 that was great. For more info go to Novak Adaptors website and read up on the transmissions there. They give good info which will help you decide on the swap.

    Here's the link

    http://www.novak-adapt.com/knowledge/knowledge_gateway.htm
     
  7. May 26, 2004
    dauntless_powered

    dauntless_powered SUB Chief

    Groton, CT
    Joined:
    Nov 3, 2003
    Messages:
    1,000,069
    my t-15 seem sjust fine fo rme, i have experianced a couiple times offroad when i wished i had something intbetween, but not often. on road im fine
     
  8. May 26, 2004
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
    Joined:
    Jul 30, 2003
    Messages:
    7,916
    JK, unless I am missing something here, regardless of 3 sp or 4sp, high gear is always going to be a 1:1 ratio; unless of course we are talking 5 speed overdrive trans. Although there may be differences in ratios between 1st, 2nd, and the 4 speed 3rd gear, high gear ratio will be the same.
     
  9. May 27, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    JIm,

    That is my point also. What I think the issue with the 3 speeds is, is that they are a compromise. They lack a compound low, and so the first gear is a little lower than the normal 2nd gear on a truck four speed. That, in turn makes 2nd on the 3 speed a little lower that 3rd on the four speed, and then you jump all the way to 1:1. Again, I have no problem with my 3rd gear as long as I drive 45 ph and above. Its the gap between 2 and 3 that is bothersome. 2nd only really wants to go 35 mph or so (unless you really over-rev it)and 3rd doesn't like anything below 45.

    JK
     
  10. May 28, 2004
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    9,490
    :? With 3.73 gears I would think you should be able to go faster than 35 without overrevving the engine. Stranger part is it doesn't like less than 45 in 3rd. I'd say you've got some engine tuning issues where it doesn't have any low end power. I'd venture to say you ought to be able to shift into 3rd at 30 mph.
     
  11. May 29, 2004
    1969_CJ5

    1969_CJ5 Sponsor

    North Carolina
    Joined:
    Feb 14, 2004
    Messages:
    182
    Not trying to Hijack here but what is a dangerous or "redline" RPM for a stock Oddfire?

    I travel a lot of highway and the speeds of other vehicles exceed 75 mph.... I usually cruise along at a snails pace of 60mph...
     
  12. May 29, 2004
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,922
    Well you figure peak horsepower is above 4000 rpm, it you were needing the extra power in a hurry I would think that the motor in good shape would hold up to 5500 rpm bursts but it should handle cruising at 3000 rpm all day long and shifting at 4000 rpm the same.
     
  13. May 29, 2004
    James P. Enderwies

    James P. Enderwies Sponsor

    Lake Havasu City, AZ
    Joined:
    Feb 2, 2003
    Messages:
    747
    I "think" the "offical" redline is 4500 rpm.
     
  14. Jun 1, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    It appears Glenn is correct. After a protracted fight with carb jets and etc., the little CJ is now happy and the perceived transmission ills have been somewhat mitigated. Of course, since I bad-mouthed the tranny, it will probably fall out.

    John
     
  15. Jun 2, 2004
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    9,490
    Just talk to it, tell it you made a mistake and beg for forgiveness. Change the oil in it too as a token of goodwill. ;)
     
  16. Jun 2, 2004
    SandhillMike

    SandhillMike Moderator

    Archer, Fla
    Joined:
    Oct 25, 2003
    Messages:
    246
    Couldn't hurt. R) R)
     
  17. Jun 2, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    My fear is that in taking your advice and pandering to the beast, a new level of expectations may be acheived, whereby I actually have to spend more time and money on this addiction. I already have a wife.
     
  18. Jun 2, 2004
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
    Joined:
    Sep 20, 2002
    Messages:
    3,617
    At the very leat ..........
    I would think a sacrifice would be in order.........
     
  19. Jun 2, 2004
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    4,922
    Maybe your wife, that would solve at least a large part of the money problem you spoke of earlier! :D
     
  20. Jun 2, 2004
    JK67CJ5TX

    JK67CJ5TX Member

    El Paso, Texas
    Joined:
    Oct 24, 2003
    Messages:
    81
    I like the way you think! She refers to my pet as a "money pit!" The joke was definitely on her and may well be again! When I saw this jeep advertised and showed an interest, she wanted to come along for the inspection and test ride! Whilst I was away, toodling around the neighborhood in someone else's jeep, she traded my Kawasaki Prairie 400 ATV for it! Bingo! I have a '67 Jeep and the toy count stays level! Well little did she know that you have to "invest" in these things to make them work. We may still want to consider a shinier tranny anyway!

    JK
     

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