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.

th350 to 700r4 - I've searched for hours

Discussion in 'The Garage' started by crawlink5, Dec 15, 2003.

  1. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    th350 to 700r4 - I\'ve searched for hours

    Well, I've searched for hours without finding exact answers.

    I want to swap my th350/203 for a 700r4 and re-use my 203. The labor and tech side to do this is quite easy as I've done plenty of trans swaps before on cars. I've put a 700r4 in a 4-speed camaro before - no problem.

    Here's my problem:
    How can I tell a K-case 700r4 from a regular? Is there a diff in the 700r4s K and non-K like the 350/400s? I found the difference in th400s through a search. If I don't know what I'm talking about some shop or junkyard is gonna have a field day without vasoline. What vehicles can I tell them I need a trans for without having to explain much to them?

    Here is what I found:
    -need an adapter from http://www.exaxt.ca/misc.asp . As I understand this it will move everything back 1.5 inches

    -so driveshafts will need to be shortened/lengthened.

    -Did any 700r4s come with 203s?

    -Will need another bracket for the TV cable to connect to the carb, junkyard

    -Will need to drill holes in frame, etc. for cross-member movement

    -If I want the torque conv to lock up I'll have to make a manual switch or buy an aftermarket switch. According to http://www.transmissioncenter.net/700r4.htm it only overheatson 84 and older trans if you don't hook this up.

    -Get one 1987 or newer. 86 and below were trash.

    Anything else?

    Thanks for the help,
    Doug
     
  2. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    Re: th350 to 700r4 - I\'ve searched for hours

    [ QUOTE ]
    1.-Did any 700r4s come with 203s?


    2.-If I want the torque conv to lock up I'll have to make a manual switch or buy an aftermarket switch. According to http://www.transmissioncenter.net/700r4.htm it only overheatson 84 and older trans if you don't hook this up.

    -3.Get one 1987 or newer. 86 and below were trash.

    4.Anything else?

    Thanks for the help,
    Doug


    [/ QUOTE ]
    1. No, 203's and 700's were ever put together.
    2. I have an 85' with the lockup disconnected, it doesn't overheat but I have both the rad. cooler and stacked plate in front of the rad. All you need is a toggle, wire, plug, and a 5 way relay to make the lockup work. I can provide a writeup for anyone interested in a few weeks when I do mine.
    3.87' is basically the year when they didn't have much problems with the 700's. 85' and 86' aren't necessarrily trash because they went to the 31 spline shaft instead of the 84 1/2' and earlier 27 spline shafts. 82' to 84' had a lot of problems. If you find a 86' and earlier it isn't trash because chances are it's been upgraded allready.
    4.yeah, basic ingredients for a trouble free 700... 10 or 13 vein pump,extra clutches in 3rd&4th. some kind of positive shifting device either a shift kit or corvette servo,junk the adopted th350 rear planetary gears for later model 4L60 parts, factory sun gear is known for a weak link... get an aftermarket one(mine is called the beast), if some good power is being made an aftermarket converter with a billet center is a good idea because the stock cast one can snap.
     
  3. mike reeh

    mike reeh 1/2 ton status

    Joined:
    Jul 23, 2001
    Posts:
    752
    Likes Received:
    0
    Location:
    San Diego, CA
    Re: th350 to 700r4 - I\'ve searched for hours

    [ QUOTE ]
    How can I tell a K-case 700r4 from a regular? Is there a diff in the 700r4s K and non-K like the 350/400s? I found the difference in th400s through a search.

    [/ QUOTE ]

    yes theres a huge K cast into the case.. If you can get a K-case, DO IT!

    mike
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,063
    Likes Received:
    70
    Location:
    Pleasanton, CA.
    Re: th350 to 700r4 - I\'ve searched for hours

    Something everyone has overlooked so far is that fact that you will need to replace the output shaft with one from Advance Adapters. This shaft is shorter than the original 700 shaft allowing you to bolt the 203 behind it. Do not try to cut the factory shaft shorter as there won't be enough spline engagement. Your original TH350/203 adapter is what is needed to mate the 700/203.
     
  5. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    Thanks for the info. As far as horsepower in front of the trans, I have a mostly stock 400 small block. Won't be changing this except for the Jacobs ignition that already exists and I'm putting on a Holley fuel injection. Mostly looking for smooth performance not high perf.

    That is a huge K - can't miss it.

    Does anyone know a good source for the planetary gears/sun gear?

    How much does the length change if I used the short shaft instead of the adapter plate?

    Thanks
    Doug

    EDIT: AA Short Output Shaft http://eshop.advanceadapters.com/commerce/catalog/product.jsp?product_id=1516 CUSTOM SHORT OUTPUT SHAFT, USE WHEN SWAPING A TH350 FOR A 700R-4 TRANSMISSION. I'd rather do this than add the cheaper adapter that lengthens the package. Thanks
     
  6. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    [ QUOTE ]
    [ QUOTE ]
    How can I tell a K-case 700r4 from a regular? Is there a diff in the 700r4s K and non-K like the 350/400s? I found the difference in th400s through a search.

    [/ QUOTE ]

    yes theres a huge K cast into the case.. If you can get a K-case, DO IT!

    mike

    [/ QUOTE ]

    This sounds like it might be hard to get. Are they rare? Expensive?
     
  7. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    K cases were only installed in 4WD applications from the factory. The housing is a bit thicker, to handle the extra stress of having a transfer case hanging off the end. So since they came in 4WD's, they aren't terribly rare. /forums/images/graemlins/cool.gif

    Look for an inspection cover that is made of thick aluminum and is held on with machine thread bolts. Non-K cases have a thin sheet metal cover that is held in place by sheet metal screws. /forums/images/graemlins/shocked.gif
     
  8. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    Thanks,

    There's one in the paper, but the man said he has two, one from a 2.8 ($400) and the other from a 4.3 v-6 vortec ($600).
     
  9. k5guyva

    k5guyva 1/2 ton status

    Joined:
    Oct 26, 2003
    Posts:
    165
    Likes Received:
    0
    Location:
    Southeast VA
    Re: th350 to 700r4 - I\'ve searched for hours

    There are enough failures in 700r4's that you should really get a rebuilt one, unless you like premature failure. For the difference in the money, you can get a good one.

    700r4 rebuilt for $866.
     
  10. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    He said the $600 trans has been recently rebuilt along with the motor. But, I don't know that for a fact. I'm checking locally for one from a reputable dealer. I REALLY don't want to do this twice. Price difference isn't enough to justify it.
     
  11. mike reeh

    mike reeh 1/2 ton status

    Joined:
    Jul 23, 2001
    Posts:
    752
    Likes Received:
    0
    Location:
    San Diego, CA
    Re: th350 to 700r4 - I\'ve searched for hours

    [ QUOTE ]
    How much does the length change if I used the short shaft instead of the adapter plate?


    [/ QUOTE ]

    exactly 1-3/4" longer

    mike
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,063
    Likes Received:
    70
    Location:
    Pleasanton, CA.
    Re: th350 to 700r4 - I\'ve searched for hours

    The length difference is actually 1 7/8"
     
  13. mike reeh

    mike reeh 1/2 ton status

    Joined:
    Jul 23, 2001
    Posts:
    752
    Likes Received:
    0
    Location:
    San Diego, CA
    Re: th350 to 700r4 - I\'ve searched for hours

    no, its within 1/32" of 1.75"

    mike
     
  14. k5guyva

    k5guyva 1/2 ton status

    Joined:
    Oct 26, 2003
    Posts:
    165
    Likes Received:
    0
    Location:
    Southeast VA
    Re: th350 to 700r4 - I\'ve searched for hours

    When you get it, and you have it out, I would put a Corvette servo in, and a shift kit (assuming this is a daily driver). It will make the shifts more crisp and make the transmission last longer.
     
  15. jwduke

    jwduke 1/2 ton status

    Joined:
    Aug 25, 2001
    Posts:
    721
    Likes Received:
    0
    Location:
    Ice Cream Capital of the World, IA.
    Re: th350 to 700r4 - I\'ve searched for hours

    Thats what I did to mine, and I've yet to have any problems with mine.
     
  16. k5guyva

    k5guyva 1/2 ton status

    Joined:
    Oct 26, 2003
    Posts:
    165
    Likes Received:
    0
    Location:
    Southeast VA
    Re: th350 to 700r4 - I\'ve searched for hours

    I've added a few more things to mine, but if you have it out to be rebuilt, it doesn't cost much more to build it the way you want it.

    I know lots of people wheel here, and that's cool. I like to smoke Honda's off the line at a light. /forums/images/graemlins/eek.gif Imagine a nasty, 6000 lbs, V8 rust bucket taking a nitro, major mod Honda off the line and keep getting it. I love my Blazer. /forums/images/graemlins/thumb.gif
     
  17. Blazr77400

    Blazr77400 1/2 ton status

    Joined:
    Aug 31, 2001
    Posts:
    652
    Likes Received:
    0
    Location:
    Ogden, UTAH
    Re: th350 to 700r4 - I\'ve searched for hours

    Another thing to consider if you dont want to pull the trans all the way apart is to run a spacer between the trans and the adapter to account for the extra length on the shaft. On mine I used an AA short shaft, but I had to pull it down for some other upgrades anyways.
    Also,the spacer would probably be cheaper if cost is an issue.
     
  18. crawlink5

    crawlink5 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    431
    Likes Received:
    0
    Location:
    Spring, TX
    Re: th350 to 700r4 - I\'ve searched for hours

    Thanks for the info.

    Ended up buying the one from K2Orion. Already has the short shaft.
     
  19. 73K5Kid

    73K5Kid 1/2 ton status

    Joined:
    Sep 24, 2002
    Posts:
    583
    Likes Received:
    0
    Location:
    chandler az
    Re: th350 to 700r4 - I\'ve searched for hours

    I moved my engine forward a 1 3/4. So you don't have to mess with drive lines. I also used a 700r4 out of an 87 blazer to mate to my 203.
     
  20. homerman5409

    homerman5409 Registered Member

    Joined:
    Dec 12, 2003
    Posts:
    7
    Likes Received:
    0
    Re: th350 to 700r4 - I\'ve searched for hours

    By moving the engine forward did you have to make any mods to the engine or trans?
     

Share This Page