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.

700R4 Tranny Sucks????!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88k5canyon, Jun 19, 2002.

  1. 88k5canyon

    88k5canyon Registered Member

    Joined:
    Jun 19, 2002
    Posts:
    27
    Likes Received:
    0
    Location:
    Layton, Utah
    I was reading an article in of the recent popular mechanics when i ran across something that implied that GM's 700R4 transmission one of the worst ever produced and that every truck that has one should be changed over to a TH400! Is this true and if so how hard is the conversion over to TH400?
    Thanks,
    David
     
  2. arq

    arq 1/2 ton status

    Joined:
    Jan 17, 2001
    Posts:
    2,017
    Likes Received:
    0
    Location:
    Imperial Valley/Maricopa
    i guess it all depends how hard you're gonna runn it. early versions of it were caca, but they seemed to improved them a bit. lot of people here run them, just gotta get someone good to build them. i personally don't have one but am wanting to swap one in my 71 grocery getter /forums/images/icons/cool.gif

    ARQ.
     
  3. bajaviking

    bajaviking 1/2 ton status

    Joined:
    Apr 10, 2002
    Posts:
    752
    Likes Received:
    2
    Location:
    Baja
    I have one and I have driven my truck about 30,000 miles the last 2 years without any problems. I guess it depends on how much power your engine makes and how hard you drive your truck. I guess towing, big tires and a heavy right foot is hard on any transmission.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    As with the Olds diesels (which also had some early problems) if someone were to tally up the failure rate from the beginning of the 700 till now, I'd bet its pretty high.

    However, GM didn't go out of their way to make sure these trannies last, by either owner education or auxiallary cooling, until much later than they SHOULD have.

    I doubt its one of the worst, or they wouldn't still be using it. (albeit with a different name and no TV cable : )
     
  5. 86blazerk5

    86blazerk5 1/2 ton status

    Joined:
    Aug 9, 2000
    Posts:
    387
    Likes Received:
    0
    Location:
    Hagarstown, Maryland
    I had mine profesionaly rebuilt when mine went out and i really ike it now. I have had some problems since the rebuild. But it was all simple warenty stuff, I had a leak once as a result of a messed up torque converter, and I have had to put a fly wheel or twon in it. But The thing is solid and runs great. You dont want to switch to a TH-400 if the truck is your daily driver. Your gas milelage will be horible if you do any highway. There is no overdrive in 400s. So if it is a moslty offroad truck I would say find a 400 when your 700 breaks, but if its a daily, just have someone rebuild it High performance Heavy Duty, or buy one from Jet Performance, or Raptor or something like that.
    Ike
     
  6. sapper

    sapper 1/2 ton status GMOTM Winner

    Joined:
    Jul 11, 2001
    Posts:
    3,052
    Likes Received:
    0
    Location:
    NoVa
    last years 2nd place TTC winner has one /forums/images/icons/shocked.gif /forums/images/icons/shocked.gif
     
  7. fad2blk99

    fad2blk99 1/2 ton status

    Joined:
    Feb 19, 2001
    Posts:
    860
    Likes Received:
    0
    Location:
    Charleston, SC
    Calling the 700r the worst tranny of all time is nothing short of ridiculous! Although, it does have its issues, I would not hesitate to put one behind an engine producing 400+ ft/lb torque--after a message from a good tranny mechanic, of course. /forums/images/icons/wink.gif
    Are you contemplating a running a 700r4?
     
  8. trailblazer87

    trailblazer87 1/2 ton status

    Joined:
    Jun 11, 2002
    Posts:
    707
    Likes Received:
    0
    Location:
    Madera, CA
    The 700r4 has two features over that of all other pre computer chevy trannies. Lowest first gear of ALL auto boxes and over drive. If you are into rock crawling or ever play in the snow the 700r4 has the advantage over the three speed slush boxes. Pre-'86 700r4's were very weak, after that chevy increased their strength and now you can find them in motor homes. The main weakness of the 700r4 was the fact that it only had 6 clutches, aftermarket rebuild kits give it 9, making for much less slippage and more positive shifting, which decreases heat, the 700r4 is very sensitive to heat, above about 180 degrees and you'll start burning the clutches, and since in most vehicles it is cooled by the radiator and engines run at 200+ you can see the problem. The other weakness of the 700r4 was its overdrive sun gear, this has just recently been addressed and you can now find rock solid 700r4's out there stronger than the th350. The th400 is a little stronger due to its heavier case, but the problem with it is that it doesn't have OD, and you'll not be able to run the higher axle gears comfortably on the freeway. Hope this helps.
     
  9. scrappyk5

    scrappyk5 1/2 ton status

    Joined:
    Mar 17, 2002
    Posts:
    2,099
    Likes Received:
    0
    Location:
    virginia
    i love driving my trucks with the 700r4's going up and down the highway , but they are very sensitive to heat.
     
  10. m j

    m j 1/2 ton status

    Joined:
    Dec 28, 2001
    Posts:
    4,606
    Likes Received:
    0
    so what tranny gets the title
    'worst tranny'
     
  11. fad2blk99

    fad2blk99 1/2 ton status

    Joined:
    Feb 19, 2001
    Posts:
    860
    Likes Received:
    0
    Location:
    Charleston, SC
    The TH200 4R?!?! Actually, thats a good question. I just know the 700r is way too popular (amoung hot rodders and 4 wheelers alike) to call it the worst.
     
  12. m j

    m j 1/2 ton status

    Joined:
    Dec 28, 2001
    Posts:
    4,606
    Likes Received:
    0
    you should try a search on 700r4 on this forum and count how many 'blowed up real good' type stories there are vs other trannies available.
     
  13. BILLY RAY

    BILLY RAY 1/2 ton status

    Joined:
    Dec 8, 2001
    Posts:
    1,319
    Likes Received:
    0
    Location:
    Austin, Tx.
    Build the damm thing right the first time and you won't have a problem. Most of all don't get some cheep torque conv. for it make sure the fins are welded. /forums/images/icons/grin.gif
     
  14. fad2blk99

    fad2blk99 1/2 ton status

    Joined:
    Feb 19, 2001
    Posts:
    860
    Likes Received:
    0
    Location:
    Charleston, SC
    I see what you're gettin at. I rebuilt mine twice (in 6mos.) before going to a Muncie 4sp. in a previous Blazer, but that's where the "qualified mechanic" comes in. Many people make the fatal mistake of assuming the TH700r4 is just like a TH350, but with overdrive. From what I've been told by reputable mechanics, the 700 is like no other (with the exception of its predecessor, the 4L60E). One thing I learned the hard way was the TV cable is the 700s life line (no pun intended) /forums/images/icons/smile.gif You screw that up and your beloved tranny can be history in matter of a few miles. The second thing I learned (and this is after the second rebuild) is go with the heavy duty sun gear. I could go on, but you get the point. The 700 is a delicate tranny, but if its good enough for my brother's street/strip, full-bodied, 500+ Tq/HP Trans-Am with 305/50/15 BFG Drag Radials (sorry, can't remember the quarter mile ET), then its good enough for the average off-roader looking for an extra gear to offset those 4.88's in the pumpkin.
    Has issues??? You bet! The worst tranny??? Absolutely not!!
    But that's just my opinion. Any other votes for "the worst tranny"?????
     
  15. m j

    m j 1/2 ton status

    Joined:
    Dec 28, 2001
    Posts:
    4,606
    Likes Received:
    0
    I would vote for the T5.
    drag cars are much easier on parts then 4x4s
     
  16. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Joined:
    Nov 28, 2000
    Posts:
    3,112
    Likes Received:
    1
    Location:
    Western Massachusetts
    But remember too, the old 700's aren't the new 700's. Talk to mechanics who have been in the "Game" for a while and ask them how good the HEI ignition did at first, and the first EFI system. Will a 700 take the torque of a 400...... NO, but can it last with a performance 350 or stock big block ......yes if built correctly. The 700 has been a product of evolution. It was piss poor to start with and along the way it was improved to what it is today. Would I use a stock a 82 tranny in my truck....NO, but do I used one behind a VERY healthy SBC to pull a 45,000 lbs transfer sled.......yes. It's all relative. Of all slushboxes I would say the old dodge/mopor electronic 3 speeds were the worst, for GM I would have to say the TH350C (not the regular 350). Everybody raves about the 400 and it is an excellent (if not the best) tranny right out of the box that will take alot of torque, but I know guys running mud trucks with Nitrous fed BBC's and they swear by the built 350's or the built 400's so who knows (this is one of those debates that could go on forever). In the end is the 700 the worst tranny (it all depends on which one you get....) /forums/images/icons/shocked.gif /forums/images/icons/confused.gif
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    200-4R can be built just as strong, if not stronger, than the 700. It just didn't get the life span of the 700 to continue its evolution, so there aren't nearly as many "out of the box" good 200-4R's as there are 700's.

    Never heard of a GM auto that was bad out of the box and never got better, at least in the past 30 years. Even the 200C (metric 3spd lockup) was used with success for many years, and although it wasn't the strongest, GM was smart about what applications it was installed in. (probably same as the TH250..not common, but still no real complaints trhat it didn't last when factory installed)

    Putting the wrong engine up against the wrong transmission or in the wrong vehicle is a sure fire way to have problems, and thats exactly what GM did with the early 700's.
     
  18. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

    Joined:
    Dec 10, 2001
    Posts:
    6,125
    Likes Received:
    53
    Location:
    Powell, Wy
    I have gone through 4 of them 700's in 2.5 years. The first rebuilt was update to the 87 standards. Then lost the pump, then lost pump and converter, then lost clutches again. Last time I just put a TH400 in it's place, worse gas mileage but cheaper than replacing tranny's every 2 weeks.
     
  19. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Joined:
    Nov 28, 2000
    Posts:
    3,112
    Likes Received:
    1
    Location:
    Western Massachusetts
    Who did you have (re)build it and what did they use for parts?
    A bad T/C could have caused the first pump to go, and then when it finally died took out the second pump. The bands may have just been "checked" and not replaced and finally went (which will eventually happen to all autos), also as the pumps were on there way out, they may have not supplied enough fluid/pressure to the bands causing premature failure. If EACH and EVERY part was not inspected during each teardown/rebuild/update, you will get the problems you described. Not saying you shouldn't have gone to a 400 (not sure what your driving), but if built correctly the first time, you should not have had those problems with the 700.
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    I'll stand by my manual transmission any day. : )

    Not that autos can't be built strong, but there are lemons produced (as in everything thats mass produced, there will be a bad part now and then) and on top of that, auto trannies REALLY need a thorough build, with all the specs checked...a quickie rebuild probably won't involve much of that. As well, not upgrading that one part just means its the next weakest link...when rebuilding, all updates should be incorporated in an auto transmission. Its false economy not to.

    The converter issue is another one, I had a rebuilt converter tear my pump up (TH400) and it was a poorly remanned converter that was too thin...I re-used it, but really, with all that metal traveling in the system, its not wise to re-use a converter that was in a tranny that failed and sent crud through everything.

    Not saying your builder sucked, but after that many trannies, I'd suspect something was up. If he didn't try to sell you all the new parts, hes as bad a businessman as he is a tranny builder : )
     

Share This Page