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.

non lockup converter on lockup th350 trans?

Discussion in 'The Garage' started by R72K5, Mar 21, 2005.

  1. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    will it work ? i dont care about losing lockup, so dont even mention lockup

    i just want to know if ill have the three forward and also the reverse ranges if i stuck a non C converter on a TH350-C

    C shaft appears longer overall than a non-C shaft,


    no splines on end of the C shaft, but other wise still has same set of two splines as a non C shaft has, but also has extra langth of non splined shaft, humm..

    thanks
     
  2. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    i know someone knows this answer

    please answer,.,..

    thanks
     
  3. 75-K5

    75-K5 3/4 ton status

    Joined:
    Apr 28, 2002
    Posts:
    5,353
    Likes Received:
    0
    Location:
    Anderson, Indiana
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    I searched for answers for you, but couldn't come up with anything.

    If I had to make an educated guess, I'd say no, they won't interchange. The lockup trannies I've dealt with (200-4R) have a different input shaft design than non-lockup, with the little check valve or whatever it is in the very tip. That should increase the overall length of the shaft and how far it protrudes into the converter.
     
  5. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    yeh the C trans shaft has an O ring on it almost at the very end of it and is not splined

    the non C shaft is splined and is missing the very unsplined end and o ring deal

    i put the non C converter on the C input shaft and it seems to click a couple times and engage, but im not 100% for sure ??


    seems fine though..

    i dunno.


    someoen has to know something,,.


    only reason i need to put the non C converter on the C trans is cuz the C trans is a diesel one and i dont have a C gas converter to put on it so i can put the trans in the 84 with gas 350... and i want to use the diesel th350 cuz its really super heavy one :D

    gonna make it a point to snag onto any diesel auto trannies i ever come across in the future,

    thanks
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,537
    Likes Received:
    923
    Location:
    Massachussetts
    I would use ..

    I'd use the diesel converter in the diesel tranny,even with a gas motor--I dont think the stall speed is so low it will stall the gas motor or anything--my friend did 2 455 olds into former 5.7 diesel trucks and used the diesel converters and tranny's,one did stall at times,so he put a gas converter in it, but it still acted up--we think the tranny was screwed up,not the converter(they were both TH400's)

    The other diesel tranny and converter seemed fine-It felt like a much more positive "engagement" with the diesel converter,like less "slippage",and shifted kinda firm,but early,due to the govenor springs being different for a diesel--a gas tranny's govenor slid right in-fixed that problem in 5 minites...

    -I drove both of them,I think the one that stalled sometimes had a valve body dilema or something,it acted like it went into 2 gears at once and locked up,and would kill the motor when you stopped at a redlight,like a lock up that wouldn't unlock!(but it was a TH400!)--weird thing was you could start it up again and drive normally for a undetermined distance,when you came to a stop you never knew if it was going to stall or not- -so he got another tranny..never seen another TH400 do that since!.:crazy:

    I think I read somewhere the TH350C tranny can only use the matching lock up converter,something is different in the hydraulic sytem on the lockup ones if I remeber right,has to do with the cluctch plate inside I think..cant remeber which book--I'll try to see if I can find out more info for you...:crazy:
     
  7. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    yeah but se i couldnt care any less about losing the extra hydraulic and the converter clutch and crap

    i really dont care about losing that

    i just want to use the gas converter on the DX th350 if it physically will

    thats all..

    and diesel converter just sounds like its just way too low of stall speed

    i dont want to lose stall speed at all, gm gas converters are plenty too low of stall speed as they are in stock form, let alone a diesel one on a gas engine, you just wouldnt have any torque at dead stop acceleration at all, would be horrible, especially in a heavy truck

    so i wont be doing anything with the diesel verter cept hauling it with scrap iron load to peoria scrap yard for scrap money, i just have no use for it and will not use it, and i really even hate the idea of usign a stock gas one, but i have to for now til i can afford a 2k or 2500 one, i want the 350 gas engine to kick'er up when i go to accelerate from dead stop, plus to help overcome that crappy ass 2.73 axle

    imagine trying top run a gas 350 and diesle verter and 2.73 gears


    theres just no freaking way.,.,,

    its way plenty horrible enough with a stock gas verter.,.

    GM is gay as hell for putting 2.73 with the gas chevy engines,

    but with the oldsmobile gas engines liek the 425, 403, 455, etc they ran 2.21 ratio in the big cars extremely commonly and they would flat out haul some ass and would whip around like an escort if it could have a BBC put in it,

    the olds engines had some real crazy awesome low RPM torque output, ive driven and owned plenty different ones to know, 77 electra 403, 79 caddy limousine 425, 74 delta 88 455, etc etc, they are some real quick big cars now! and with even more horrible gears than 2.73 to boot!


    bottom line is i cant use the diesle verter behind the stock 74 CMJ 350 engine in the 2.73 pickup, i already know it will kill it everytime i even attempt to get going from a stop

    its way horrible enough as it is with the original stock SM326 three on the tree, you have to burn the hell out of the clutch to get it going just how it is right now, unloaded even..

    so..



    thanks
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,537
    Likes Received:
    923
    Location:
    Massachussetts
    Gm was stupid at times...

    I agree GM put some insanely high ratio gears in the 90's cars and trucks when fuel economy was their main goal,at the expense of ruggedness and longevity--I had an '80 El-Camino with a 267 V8 and a 2.56 Posi!--it would hardly spin the tires on sand!(but did nothing but slide sideways on ice,would not go foreward!)--it got great gas mileage though,and cruised at 80 mph like nothing--a real dog on takeoff though..didnt win any stoplight drags in that thing--

    The 82 GMC Cabalro I had with a 229 V6 and 2.56 gears was even worse!--felt like it had a Briggs and Stratton under the hood--but it was economical..

    Another guy I know had bought an old telphone company chevy C10 that had a 250 six and a 5 speed factory,I think it was an overdrive,like the ones a chevy monza used--it had 2.56 gears as well,and you had to burn the clutch at every stoplight to get it moving--it felt like taking off in second or third more than first!--we ended up putting a TH350 in it,and a V8 eventually--it was like a whole different truck after that...

    All I can say is if your willing to risk having to pull the tranny out again is to throw in the gas converter ,run it,and see what happens!--I looked in all my books here,I must have read that thing about the lock up converters in the books at my friends shop--if I go there I'll look there and see if I can find any more info..:crazy:
     
  9. beater_k20

    beater_k20 Banned

    Joined:
    Dec 9, 2003
    Posts:
    10,276
    Likes Received:
    0
    Location:
    Elkhart, IN
    it wont work. IIRC your TH350C should have 3 splined sections on the input shaft, and a TH350 only has two. the lack of the third splined section will cause a leak inside the converter, and it will not work. it MAY work for a short period of time, but it wont last.
     

Share This Page