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2.73 axle with auto trans vs. manual

Discussion in 'The Garage' started by R72K5, Jan 1, 2005.

  1. R72K5

    R72K5 Banned

    Mar 5, 2001
    Likes Received:
    central IL
    everyone knows that 2.73 is horrible axle ratio any way you look at it,

    im gonna be going to th350 in the 84 real soon away from the three speed saginaw, its just too hard to get the truck moving from dead stop, burns on the clutch lugs the engine and drivetrain too low of rpm

    but how much you think th350 will help in getting the truck moving ? im still gonna want to go to 3.73 14 FF like i have had planned, right ?

  2. fatbob

    fatbob 1/2 ton status

    Jul 3, 2003
    Likes Received:
    Phoenix, Az
    I had a 350/th350/205 & 2.73 and it got around pretty good with 32" bfg's.

    I got 14-15 mpg also so I think its a pretty good setup for a daily driver.
  3. diesel4me

    diesel4me 1 ton status Premium Member

    Jul 24, 2003
    Likes Received:
    HIGH gears.....

    I have 2.73's in my 81 van--it had 3.08's originally,but the diff case wore out where the side gear goes thru,and the 2.73 ratio rear end was free,so I put it in--the van had a 250 camelhumper 6 in it at first,then I swapped in an even more anemic 73-307 V8--I thought it was a dog with the 3.08's--the 2.73's are even worse, I thought it would not make much difference,but you can feel the power loss even though its not that much higher a ratio--
    It does ok with the TH350 lockup tranny in it,its just not a ball of fire upon takeoff-- it does get good gas mileage on the open road--but climbing hills in VT and NH were a challenge,had to downshift into 2nd gear quite often(it will go 75 in 2nd gear before upshifting to 3rd by itself,not even winding out that high!)--looking back I wish I'd have bought the axle in another junkyard van that had 3.42 gears--its pretty rare to see anything lower than 3.08 in a G10 van here--I think the 307 would like being revved up higher,its short stroke makes it a poor lugging motor.

    Your truck must be hard to get moving from a stop,as you said the clutch will be getting a beating if you have to ride it a lot on takeoff--I know of one C10 my friend bought from the phone company,it had a 250-6,a five speed manual tranny,(the crappy monza type tranny)and 2.56 rear end gears--it was all you could do to get it to take off on a hill,and the clutch would smell like it was burning all the time!--we put in a 350/TH350 from another parts truck--it was much better,the motor had no problem pulling that high gear,and it got good gas mileage--it might not have been an ideal gear for towing heavy loads or trailers,but he just used it for transportation anyway..

    If you put a 14 bolt in it,are you going to change the front spindles so 8 lug wheels fit all around (I'm assuming your truck is a C10?)--I thought you could just swap the spindles,but the guy at the boneyard claims the ball joints and A-frames are different too,and you have to swap everything--others have said you can put 8 lug rotors on the 1/2 ton spindles by juggling the wheel bearing races and cups with different I.D's in them to "adapt" them--I looked into putting 3/4 ton suspension in my C10 when I thought I might put the caddy 500 motor I have in it,but decided it was too big an undertaking for me at this time-and I never got the "answers" as far as making the front 8 lugs to match the rear..:crazy:
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Jul 23, 2000
    Likes Received:
    E-town baby!
    When I first got my Jimmy it had the 465/NP208 and 2.73's with 33" bfg mudders on it. Starting in second like you're supposed to was out of the question...the clutch would chatter and burn.

    I used granny first and shifted it like a regular four speed and it worked fine. Fourth ended up being the equivalent to an overdrive, and I often got 15+ mpg on the freeway. Freeway rpm's were 1850 rpm at 65 mph...just loafing along.

    When my first 14 bolt/D44 got swapped under the truck they had 3.73's...and it was a very nice ratio for up to 35's (with the SM465 anyways)


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