th400 vs 4L80e transmisssions

I have a 75 chevy 3/4 ton 4x4 with a 1 ton rearend. I have to replace/repair/rebuild the motor and would like to replace the transmission when i pull the motor. which would be better th400 or 4L80e? I want the automatic, i really want an overdrive. i use my truck mainly to cut and haul wood as well as haul junk, i do occasional trailer pulling, and hunting. i want the overdrive for highway travel. I believe it is equiped with a 350 turbo tranny now. i am unsure of the transfer case, it is full time four wheel drive (meaning i have to engage the  transfer case=4-hi 4-low 2-hi n, but does not have lock outs) of course cost is also an issue since i will have some money wrapped up in the rebuild. 350 v8 motor. any helpfull suggestions or advice would be great. also help on identifing what i got would be cool too. thanks in advance.  

TH400's are famous for being strong, I don't know how long 4L80E's last. The TH400 will give you the same final drive as a TH350 will, unfortunately. If you find out you don't want a 4L80E, Gear Vendors makes overdrive (0.78:1) units that can add onto any tranny (for about $2000, plus you need a shorter driveshaft)  

The 4L80E is basically an electronically controlled TH400 with the overdrive gear. It's just as strong as the TH400, however, you need the right computer to control it. Depending on your truck, the doner truck and what you can salvage off of it, the 4L80E would give you the overdrive gear. If cost is a big factor, go with the TH400. But if you can get the computer, and you can deal with the headache of attaching it to the tranny and other inputs needed to run correctly, the 4L80E will give you the overdrive you want.  

"Advance Adapters" might sell 'stand alone' 4L80E's. (so your engine doesn't need to be computer controlled) They might even come with the computers...  

Someone from work suggested a 700r4. i have noticed the r4's are cheaper and i have been told they can be built with very good strength, and offer a good over drive gear. why buy a $2000 $$$ bolt on? is it not possible to get a tranny with a strong first and second and decent overdrive?

The 700r4 is a good tranny but unless if I am mistaking if was mostly used in 1/2 ton applications. This may make it a little weak for your application. If you do go with a 700r4 make sure it is from a later model truck, because they came stronger stock and will require less upgrading. I would go with the T400 because they are fairly bulletproof and wont need a computer to run it. Then, when you have the money you can buy the aftermarket overdrive which is another bulletproof add-on.

Tony

The 700R4 was in 3/4 ton applications as well. I have a 91 k2500 at work that came with a factory 700r4. With that being said, that truck has also been through 3 trannies. It is also a fleet vehicle (too many drivers) and did have a plow on it for 10 years.

I have a 700r4 in my 92 k1500 with a B&M shift kit in it with 150,000mi on it and it is still going strong. It only has a warm 5.0L in front of it, but i subject that trans to some pretty heavy towing. So far it has been good to me.

The early 700r4's are notoriously weak, which has given them all a bad name. The later versions are a good trans and can be built to handle power. 

No computer is required for most 700r4's. The computer controlled 700r4 was renamed the 4L60E in 92-93 c/k trucks.

okay just to let you all know what i have found out in the last week.
    a 700r4 is probabaly not as strong as a th350 or th400, but it does have an overdrive, but by time you buy one ($1000), buy the adapter, spend the time and money to fit it all together ($1000), like someone said earlier, it would be cheaper to buy a gearvendors over/underdrive and just bolt it on and shorten the drive shaft. of course the cost figures the same or worse for a 4l80e, due to the electronics. thanks for all your help.

ps i am gonna try to buy a gear vendor over/under on ebay and see if i can save some *** anyone got another name of an over/under drive vendor???