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Which is stronger SM465 or TH400/475

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Batmanjr, Jul 29, 2001.

  1. Batmanjr

    Batmanjr 1/2 ton status

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    Which one is stronger a SM 465 or a TH 400/475. I'm trying to get an idea of what is going to hold up best in the long run.
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The TH400 or 475 is a very strong tranny...but I'd still say the SM 465 will take more abuse for longer and still live.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I agree, can't beat a manual for strength.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  4. Brians 60s

    Brians 60s 1/2 ton status

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    the turbo 475 is one hell of a strong tranny since it has straight cut planets, but the sm 465 is almost bulletproof. If you were to tear one down and look at the diameter of the gears inside, I think you would be impressed. I have only seen 2 sm465s break. i have seen countless 400s go south, as well as more then a few 475 destroyed in motorhomes.

    IT'S A 1 TON THING.... IF I HAVE TO EXPLAIN IT, YOU WOULDN'T UNDERSTAND!!!
     
  5. Thumper

    Thumper 1/2 ton status

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    What about the SM420?? Where do they fit in?

    Mike


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Lets Go Wheelin! </font color=red>
     
  6. newyorkin

    newyorkin 1 ton status

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    SM465 kicks arse! But the TH400/475 are the strongest GM automatics before the 4L80, I think.
    The guy I sold my old truck to somehow blew the 465 shortly after I sold it to him... Don't ask me how, it was rock solid when he drove it away...

    Ratch
    <a target="_blank" href=http://k5.8m.com>k5.8m.com</a>
    **K5 - What more is there to life?**
     
  7. '73 K5

    '73 K5 1/2 ton status

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    The SM465 is what replaced the SM420 in the late 60's(I think it was late 60's) The 420 had been around forever before that. They are almost the same, but the 420 has a lower first gear by just a little bit. 7.02 or something vs. the 6.55. I also heard its more "rough around the edges"...meaning it makes more noise and it shifts more like you're driving a tractor than a truck.

    '73 K5
    Chevy good...Ford bad
     
  8. '73 K5

    '73 K5 1/2 ton status

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    Have to say the SM465. When I bought my Blazer I changed out all the fluids. There was mud and water and a little gear lube mixed in my 465. And I'd driven it like that for a while. I put new gear lube in it and its been problem free for the last 4 years. Try the mud and water thing with an auto, and you're going to be spending some serious cash.

    '73 K5
    Chevy good...Ford bad
     
  9. DieselDan

    DieselDan 1/2 ton status

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    Just to play devil's advocate here; remember the weakest part of the SM465 is the clutch. A poor driver/technique will smoke a manual (clutch) in short order. On top of all that the U.S. military gave up on manual trans years ago (although M35s still soldier on w/a stick). Maintenance required was the issue (plus the cost to train operators how to drive a manual). Every HMMWV has a TH400 or the new 4L80E.

    That all being said, I'll still be plopping a 465 in my Jimmy soon.

    Dan W.

    Real trucks don't have spark plugs!
     
  10. mike reeh

    mike reeh 1/2 ton status

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    they're both very strong obviously.. but the 465 wins in the longevity department.. there are many untouched 465s still running around after 25+ years.. dont know of any autos, and if there are, they're on their last leg..

    mike
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    HMMWVs should not be the standard to judge how strong a tranny is. They've got gutless motors and never tow anyway.

    If you've got a good aftermarket clutch it'll take any beating you can put to it. Don't believe me? Go to the dragstrip sometime.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  12. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    without a doubt the sm465[​IMG]

    77blazer see it at<a target="_blank" href=http://community.webshots.com/user/ssmith6333>http://community.webshots.com/user/ssmith6333</a>
     
  13. Waxer

    Waxer 1/2 ton status Author

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    DieselDan is right. The clutch with the sm465 is definitely the weak point. Smoke your clutch and the tranny might still be good but your truck isnt going anywhere FAST. You'll be crawling home in 2nd or 3rd gear. The tranny itself is strong as an OX, just all I'm saying is the clutch is where all your attention will be. With the auto its the same thing, the internal clutches will wear out after a while and require a rebuild of the tranny to fix that. I just swapped in a SM465 from a th350. So I've been on both sides of the barrel here. Just my 2 cents

    Crawlin the rocks with my K5
    <a target="_blank" href=http://www.rockreadyk5.com>http://www.rockreadyk5.com</a>
     
  14. Thumper

    Thumper 1/2 ton status

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    So the 465 is a 4 spd? or 5?

    Mike


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Lets Go Wheelin! </font color=red>
     
  15. thatK30guy

    thatK30guy 1 ton status Premium Member

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    465 is the 4 speed manual tranny. The best there is, the best there was, and the best there ever will be!!! [​IMG]

    <font color=blue>Daddy told me while learning to pee......"if you shake it more than twice, then you are playing with it!!!"</font color=blue>
     
  16. Batmanjr

    Batmanjr 1/2 ton status

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    Well you were right Wes, The opinion of the site still backs you 100%. I sure do appreciate all your help and everyone else's poiints here.
     
  17. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Wes, I disagree. I WANT AN NV 4500!!

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  18. Twiz

    Twiz 1/2 ton status

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    I think it's sixes- same same same. They are all tuff trannys.

    Ofcourse, autos are going to wear internaly, but a manuals going to wear out the clutch in about the same amount of time.

    Overall rated power input rating in order I'd say it is as follows;
    N/P 465. N/P 4500. T475. T400. 4L80

    But in reality; It comes down to a matter of prefreance. My current beater/daily driver is a 465- I hate it! My project blazer had a T350 in it and I loved it (but also went threw 2 of them, before it went under the knife. The O/E trans cracked due to loose front motor mount. The second one was a crappy rebuilt unit, The third one I rebuilt with some help and have had no problems with when it was a driver)

    I think as far as wheeling goes, I'd chose the auto over a manual trans.

    Twiztid
     
  19. Twiz

    Twiz 1/2 ton status

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    Brian's 60s

    Not to start an arguement, but...
    There are thousands more autos on the road than there are manuals. So figureing that in- there are going to be way more autos being serviced than manuals. It's all relitive.

    Twiztid
     
  20. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    What do you want to drive? I gave up trying to talk anyone into either trans, it won't work. I really prefer an auto, but a manual works great when set up right too. So if you want a strong auto, use a 475, if you want a strong manual, use a 465. That's all there is to it. Comparing apples to oranges won't work. A lot of it depends on how the truck's set up and driven.

    Just to feed the fire......
    How many 32 spline TH400 outputs has anyone seen worn out compared to the 10 spline drivesleeve that needs to be replace every 80-100K miles in a 465? What happens when it breaks or strips?
    You want to go deeper, how about the "hard on drivetrain parts" factor? Is it better to have "the strongest transmission" and waste axle parts when a "weaker" trans will save the rest of the drivetrain?

    drive what you like.....
    and if you rock crawl, get an auto and learn to like it!

    Making the world better, one truck at a time.
    SW-ORD
     

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