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what trannie should a 91 burb have?

Discussion in '1936-Present Suburban' started by COCHEV, Nov 12, 2002.

  1. COCHEV

    COCHEV 1/2 ton status

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    its a 3/4 ton and its auto with OD. is it a 460le or 480le? it has the simi floater rear but is 8 lug all the way around if that matters. thanks,

    jason
     
  2. FLASHLIGHT76

    FLASHLIGHT76 1/2 ton status

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    I'm gonna go out on a limb here and say 700r4. The overdrive is usually the kicker. The semi float rear means is a light duty 3/4 ton. Also why I say 700r4.
     
  3. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    its not a 700. i do believe it's a 4l80e they have OD i think. and the semi doesn't mean it's "light duty", my 89 3/4 ton sub has an 8 lug semi and it's a "heavy duty". /forums/images/graemlins/burb.gif
     
  4. FLASHLIGHT76

    FLASHLIGHT76 1/2 ton status

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    Well arn't we just up on ourself lately. /forums/images/graemlins/smirk.gif What I mean by light duty is that it's no 14ff. The lugs really mean nothing as far as strength. And Techniquely the subs don't classify as heavy duty in these years. Something about not being offered with a 454 (4x4)only. That's why they have the semi floats and the trucks have full floats. When chevy released the new body on the truck they kept the full float only on 1tons. If you look in a shop manual at the local parts store all 3/4 tons are really light duty and 1 tons are heavy duty only in the years from 88-91ie. our trucks. The only heavy duty sub was a 2wd with a 454 and came with a 14ff. Now if we go back to the pre 88 we get the k30 and k20 subs. Ok I have used up all the remaining brain cells. ouch! /forums/images/graemlins/burb.gif
     
  5. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif well thank you for clarifying. i've been told that 8-luggers were heavy duty so i believed it.
     
  6. Living Large

    Living Large Registered Member

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    Just purchased the same style suburban 2 weeks ago. If it is the 3/4 ton with a GVW of over 8600lbs then it has the 4L80E trans. If it is the "lighter duty" 3/4 ton, then it could have the 700R. The 4L80E is a turbo 400 with overdrive. GM rates them at 885 lbs of gearbox torque which eaquals the ability to handle 440 lbs of imput torque. Overall a good trans, with ability to handle a moderate aamount of abuse. Hope this helps.
     
  7. COCHEV

    COCHEV 1/2 ton status

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    so is yours a 91, solid axle front? do you have the full floater or simi?
     
  8. Living Large

    Living Large Registered Member

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    1991, 61250 miles, with all the towing package"heavy duty? stuff" semi- floater rear end. From what I have learned, you could only get the semi- floater rear end as the "heavy duty rear" end. Hope this helps.
     
  9. u2slow

    u2slow 1/2 ton status

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    The '91 3/4-ton 4x4 Burbs I've seen (350 TBI) all had 4L80E's. They did have the 14SF rear end as well.
     
  10. chvyhs

    chvyhs 1/2 ton status

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    MY '90 had a SF rear and a TBI 350 but I think someone switched out trannies on me /forums/images/graemlins/confused.gif. It has a T400 but the shift pattern on the dash is for an overdrive tranny.
     
  11. ken

    ken 1/2 ton status

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    That's like my '90!!! Ditched the failure-prone 700r4 for a TH400 and didn't change the shift pattern on the dash!! GOD I HATE 700R4s!!!!
     
  12. chvyhs

    chvyhs 1/2 ton status

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    I'm trying to find a 480 that I can afford because I really want overdrive! Sooner or later I'm going to put those 4.88 gears in so I think the OD will be appreciated.
     
  13. u2slow

    u2slow 1/2 ton status

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    You'll need an ECM to go with the 4L80E, and a harness - not to mention different length driveshafts front and rear. /forums/images/graemlins/rolleyes.gif
     
  14. chvyhs

    chvyhs 1/2 ton status

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    I was thinking about the differances between the T400 and the 480. So it's longer and it needs a ECM harness. Is there anyway to see if my Sub already has the harness? What if I get a 480 out of a desiel? Will it be a stand alone tranny? /forums/images/graemlins/burb.gif
     
  15. u2slow

    u2slow 1/2 ton status

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    Your truck won't have the harness for the 4L80E. The TH400 doesn't have all the electronic controls the 4L80E does.

    You might be able to use the diesel tranny. I know there was issues with older non-electronic transmissions having different stall/lockup torque converters - but since the ECM controls the tranny, the gas and diesel versions should be identical.

    The diesel 4L80E is still electronic, and uses an ECM. Would be best to find one in a '91 crewcab or 3/4-ton Suburban (gas or diesel). It will be the most compatible.
     
  16. Living Large

    Living Large Registered Member

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    There might be another answer. If your suburban does not have the harness(it should if it is a 91 3/4 ton), then contact the aftermarket street rod companies. They offer a stand alone kit for the 700R, so they might have one for the 4L80E.
     
  17. chvyhs

    chvyhs 1/2 ton status

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    Thanks for the info.

    Do you guys know if it's a direct bolt in? Will the tranny to transfer case be the same adapter? Is the case any longer or shorter?

    I've thought about the stand alone kits. My brother works for Jet Performance.
     
  18. BurbinOR

    BurbinOR 3/4 ton status

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    Jason, let me know your progress on this, as that is exactly what I will be in the market for shortly. 3/4 ton 91...............
     

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