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Should bother with a 700/208?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by AussieK5, Jul 3, 2001.

  1. AussieK5

    AussieK5 1/2 ton status

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    I've got a clapped out TH350/203 combo (and a 8 lug 44 & 14 bolt 4.10 waiting to go in) just begging to be retired. I want a O/D tranny, but in this part of the world 700/208 combo's are very, very hard to come by, I've never seen one advertised, ever. NV4500 ha ha. And there is no aftermarket tranny shops that deal in chev 4x4 bits.
    What kind of MPG difference is there between O/D and non O/D?. My revs on 35s with 4.10 would be approx 1750 v 2450. Right now I get 11mpg on 33s with 3.42s
    Should I forget the O/D and just chuck in the 465/205 I've got in the back of my workshop (a lucky find one weekend), or get a J@#P 208 and try to mate it to a 2wd 700, both of these are relatively easy to locate. I don't know anything about 208s and doubt this would work but if you don't ask you don't get.
    I use my truck for as a daily driver, for towing a race car and romping in the hills, there will be some competition 4x4 action after the diff and tranny upgrade.
    Thanks in advance for any advice.

    <P ID="edit"><FONT SIZE=-1>Edited by AussieK5 on 07/03/01 05:03 AM (server time).</FONT></P>
     
  2. jarheadk5

    jarheadk5 1/2 ton status

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    If you don't have a tranny shop who can work on a 700R4, I'd go with either the 465/205 combo, or rebuild the 350/203 combo. Sounds like you'd be putting a little too much stress on the 700 for comfort.


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  3. WOODYJ

    WOODYJ 1/2 ton status

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    The 700-208 combination is hard to beat. I haven't sen one with large tires however. I have one in my rig, 383/w 373's, and 31" tires. At 55 to 60 mph I am only turning around 1750rpm's. I have to go on up to 65 to get the cam to start pulling like it should, about 2000 rpm's. Another consideration is how new the 700 is. They only put about 1000 upgrades in that tranny before they got it to run right. If it is an older one, I wouldn't mess with it. Mine has been gone through and all the upgrades have been done. I like it because the low is a little lower than the other trannys and the O/D is just an option that lets you get down the road without running so many RPM's. In your case, with the oversize tires, I would question whether your motor would pull anything at the low R's. I have been running mine now for 5 years and haven't had a problem. I am running the 208 also and really like it. Check out your R's that you would be running again. I don't think with 3.42's that you will be much off idle. Just something to think about.
    If you are going to put 4.10's in it, you may be in good shape with 33's. After that, if you don't have a good rebuilder around--don't think I would use the 700. They are good trannys, but just haven't seen any in action with big tires.

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  4. AussieK5

    AussieK5 1/2 ton status

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    Thats some good advice about the 700, I'm leaning towards the manual. Trying to recover my blazer from the boonies if I broke an auto would negate any fuel savings for some time, let alone fixing it once home.
     
  5. WhiteWhomper

    WhiteWhomper 1/2 ton status

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    This is not a bad combo if you can find it. The 700R4 has gotten a bad reputation over the years, but most of those earlier problems were remidied by around '85. Just about any transmission parts supplier can supply rebuild parts to make them more reliable. The nice thing about this combo, is that the 700 has a lower first gear along with the overdrive. the .70 gear in overdrive can actually allow you put in lower gearing which will help pep around town and while wheeling but still be respectable on the highway. The 208 t-case is a pretty reliable unit that has a good low range (2.62:1) is quiet, can be shifted on the fly, and is pretty light (about half the weight of a 203). As for not holding up to big tires...I run 36" swampers, and the tranny/t-case is one of the few things I haven't busted. When you mention trying to mate a Jeep 208 with a 2wd 700, I think you may be in for more fabrication than what it is worth.
     
  6. Steve_87K5

    Steve_87K5 1/2 ton status

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    My experience with the 700/208 in the desert and with towing is that they don't have sufficient strength or reliability. The 208: In the desert, with all 4 wheels burried in soft sand, the chain can skip. The case is also somewhat fragile, and if cracked or leaky,
    loss of lube will cause planetary to seize. The 700: I rebuilt my gearbox four times before giving up on it. They may be OK if you don't pull a trailer, or go into the desert. Just my experiences....Try to find a 4 speed and a 205.

    SteveB<P ID="edit"><FONT SIZE=-1>Edited by Steve_87K5 on 07/03/01 08:33 AM (server time).</FONT></P>
     
  7. AussieK5

    AussieK5 1/2 ton status

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    The bad seems to outway the good with the 700/208 combo, a broken tranny on a race weekend would mean I would be without a service/tow vehicle, a major pain in the as# , not to mention if it blew during the tow there and I miss a race. My minds made up, thanks for the thoughts.
     
  8. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    I can't speak for how a 700r4 operates in extreme desert temps, but I have to disagree with the comments about towing ability. I tow my travel trailer through the Canadian Rockies every summer, including the Roger's and Sinclair Passes, as well as the Highwood Pass(highest road in Canada) and I haven't had a problem. The biggest issues surrounding 700r4 failure are lack of maintenance and lack of cooling. I run a 22000 GVW auxilliary tranny cooler and change out the fluid and filter yearly. If you keep it cool and clean, your tranny won't give you any problems...............



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  9. arq

    arq 1/2 ton status

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    I live in the extreme desert temps(over 110 durring summers)and have seen two suburbans on fire due to tranny heating up. That's not including the smoky ones that are forced to pull over cause their tranny is overheating. The funny part is that non were towing anything.
    Out of the subs that caught on fire, one was carring 4 adults a baby and some lugage the other was a solo driver on the foot of the grade.
    Most of the trucks/subs were new models 1995 and newer.

    I think it has to do with speed. I recall some of them passing me up on the freeway over 80mph and about 20 miles down the road i see them on the side throwing dirt under their trucks.

    so much for the 700, not for me and not for the HOT desert temps. I'll stick to my 350 till i put the 465 in.

    ARQ.

    1-72 4x4 CST Blazer
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  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    The 700R4 is the best hydraulic transmission GM ever produced. It just doesn't like to get hot. Like someone said above, keep it cool and it'll live.

    I flushed mine with new fluid, dropped the pan and changed the filter, added a B&M stacked plate 24,000 lb. cooler, and adjusted my TV cable and my 700 works wonderfully.

    However, if anyone EVER wants to trade my 700 for an NV 4500, it's all yours. I'd give about anything for a grindbox with overdrive. I think automatics are for lazy people.

    Too bad everyone thinks swapping an auto for a manual is insane.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  11. morphed86k10

    morphed86k10 1/2 ton status

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    no 700R4 will ever come close, strengthwise, to a good 465. OD would be nice to put in some low diff gears though. And Tim, I don't think swapping an auto for a stick is insane. One of my friends is considering swapping out his TH350 for a 465 I've got laying around. That 6.55 first gear is fantastic on the trail. The weakest part is the clutch, but if you fry that with the gears you have available, I don't have any sympathy for you.
     

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