700r4 or K case 400?

Here is my plight....
Have an 86 chevy 4x4.  Someone had put a TH350 in it.  The TH 350 went south and I am having trouble coming to terms with what to put back in it, and how to go about doing it.  The truck has been sittin there for a little over a year just begging me to fix it!!!!!!  Any help in the direction I should go would be helpful.  I beleive it has the stock front and rear axles, dont know their ratio.  PLEASE HELP!!!!!!!!!!!

86 Chevy 4x4
350 sbc  

just rebuid the th350. if you change transmissions you are gonna have to make sure the adapter for the t-case will work and the trans out put has the same spline count  

Thanks for the advice, but I can't rebuild the TH350.  The casing is trash.  I have a TH400 and transfer case.  I am torn between puttin that in it, or a 700R4.  I have done a bunch of research on both, and am leaning towards the 700R4.  It kinda sucks knowing you have something on hand to fix it when you THINK that something else would be better.  I need some advice on wich way to go with this. Thanks again.  

86Chevy4x4:
Thanks for the advice, but I can't rebuild the TH350.  The casing is trash.  I have a TH400 and transfer case.  I am torn between puttin that in it, or a 700R4.  I have done a bunch of research on both, and am leaning towards the 700R4.  It kinda sucks knowing you have something on hand to fix it when you THINK that something else would be better.  I need some advice on wich way to go with this. Thanks again.

If it was my rig I'd build up the 700 and install it. The advantages the 700 has out-weighs the 400 anyday. The lower first gear and the overdrive is nice. I had a 83 Blazer with a 350/700R4/208 with 4.88s and 35s and loved it! I could cruise the highway at 85+ and climb trees in 4-low. I currently have a 91 C2500 and just installed 4.88s and 35s and its a sweet combo, even though the 4L80E has a taller first gear it helps the bottom end when towing and still cruise at 85 with lower RPMs than a 400 with 4.10s and 35s. I'd recommend the 700 before the 400 unless you plan on putting a BBC in front with lots of HP.  

Thats kinda what I was thinknin too.   I've had the TH400 setup for a little over a year now, and have done nothing with it because I was wondering if that would be the best thing to do.  Now all I need to do is get a 700R4, torque converter,  transfer case, new driveshafts, AV cable kit, new tranny cooling lines.  Man, got some work ahead of me huh?  

go with the 700 you will be a lot happier  

I have a 1984 Chevy 1/2 ton 4x4. I have installed (3) 700R4 transmissions in it. Now I am looking to install a Tubro 350.  I have the transmission but am looking for the shorter front drive shaft, Longer rear shaft and a spacer for the transfer case. I will NEVER put a 700R4 in any truck again. If you have these parts would you be willing to trade for my 700R4  ( needs new front shaft seal ) front and rear drive shafts, Both have new U-joints installed 3 years ago. I think you can use your'e old transmission fulid lines. FYI  If I were you I would put the turbo 400 in the truck.never mind the gas mileage if you want that buy a car. My trucks RPM's are around 1800rpm's at 55-60 miles per hour, The truck has no power in that RPM range I am looking to bring that up to just under 3000 rpm's. I will use more fuel but I will have more power for pulling my boat and things.  One more thing, If you have Auto locking hube, replace them with manual ones. Good luck with your'e project.  Bill.
bilces@gmail.com  

BillCes:
I have a 1984 Chevy 1/2 ton 4x4. I have installed (3) 700R4 transmissions in it. Now I am looking to install a Tubro 350.  I have the transmission but am looking for the shorter front drive shaft, Longer rear shaft and a spacer for the transfer case. I will NEVER put a 700R4 in any truck again. If you have these parts would you be willing to trade for my 700R4  ( needs new front shaft seal ) front and rear drive shafts, Both have new U-joints installed 3 years ago. I think you can use your'e old transmission fulid lines. FYI  If I were you I would put the turbo 400 in the truck.never mind the gas mileage if you want that buy a car. My trucks RPM's are around 1800rpm's at 55-60 miles per hour, The truck has no power in that RPM range I am looking to bring that up to just under 3000 rpm's. I will use more fuel but I will have more power for pulling my boat and things.  One more thing, If you have Auto locking hube, replace them with manual ones. Good luck with your'e project.  Bill.
bilces@gmail.com

If you have had bad luck with the 700 trans then you might consider installing lower gears as this is the ticket for keeping them alive. Also, if you expect any tranny to pull a load more than what it is rated for, its more than likely to go south. I've gone all different routes over the years in many trucks I've built and the 700 is good for me if I keep within its limitations. I've burned up just about every trans GM makes. If built right with all the goodies, the 700 is a fairly stout trans and can hold up to alot of torque. FYI, if you replaced your 700 with a 84 or earlier year, its kind of a given, they suck. Small input shafts will break really easy and the valve bodies are junk. I don't touch a 700 unless its atleast 85 or newer but I prefer the 87-92.    

ok guys lets go school here. to put a 700r4 in place of a 350 turbo with a 208 transfer case you only need the adapter to go between them and everthing else is the same. if you already have the 400 turbo and transfer case put it in it is bullet proof.  

before you go swapping in a 700r4, check to see if the truck is prewired for a 700r4, so you'll have your lock up, without lock up you'll cook a 700r4 in no time especially if your doing a lot of driving in OD since without lock up the converter cools poorly, also if you decide to take the turbo 400 route remember you'll need an electronic throttle kick down switch to get full line pressure at wot and get the best gearing possible, i have an 87 k10, 35's and 4.88 gears, i put a th400 in it, and it pretty much topped out around 65, i now have a 700r4, driving straight off the line 1st gear is pretty much useless, and it won't do much more than 90, but wiht 35's you shouldn't be going that fast anyways. put good gears behind a 700r4 with lock up you'll get great fuel mileage and never have transmission issues, for that carburated truck a kit to wire it for lock up is only about 70 bucks, or find a donor truck to remove one from, really simple. just adjust your tv cable properly  

The overdrive unit in the 700 is nice.  If you are not hard wheeling it i would go with it.  

In case you need.......i am parting out a complete 1984 suburban k20 with a 700R4 TRANSMISSION. I can send you pics....i am in Southern california. Get back to me at rebel_2007@verizon.net.  

This guys right,I have a 85 suburban with a 454high performance and my 700r4 can hanle it all.I haven't come across a hemi or anything that can touch me on or off road and I'm sittin on 35 bfg.Go with the 700r  

hi there my opinion don't used the 700r4 it sucks dude is great on over drive but for off road sucks if u want a good strong truck u have alots of works to do if you thinking of doing it get your self a 76 down truck or blazer but wherever you do stay with CHEVY alots of options, more power and low prices. 400 tranny 205 transfer case is the way to go  

hey i had 454 wth a 700r4 tranny no good some is wrong wth distrbutor  sending mesage to the computer over drive always burns out going wth 400 205 14 rear dana 60 short 1985 looking for 6" lift long leaft spring surburban's bigger wheel based