700R4 compatability & TH400

prariepunk

prariepunk

Active member
RE: Yep

I'm in the process of buying DEREK C's 700R4 trans. Can I get it too work with a Model20 or Dana300 TC? Does anyone offer a twin stick for a Model20 TC? And Which one is better, the TH400 or the 700R4? Reply please!
 
I can't help with what hooks up to what, but I can say the TH400 is WAY stronger than the 700.

TH400's are what's in 1ton and heavy duty 3/4ton Chevy's. However, 700's are still excellent if you don't have a TON of power, don't plan to tow very often, and want overdrive.

A 700 has about the same strengh as a TH350, if that helps in comparison at all.

What are you putting it in?
 

RE: Re: RE: sign the petition...

the TH400 is (usually, unless modified otherwise) a 3 speed transmission. The 700r4 is a 4 speed, so consider that difference. the 400 is WAY stronger, even a 350 is stronger than a 700. Cant help you on the Tcase compatability
 
There is no comparison as far as strength goes. Except for the newer super heavy-duty automatics that have come out, you won't find a tougher one than the TH400. When you start throwing the word "better" around though, it depends on the application. Do you really need all that strength? If you do need it then the choice is easy, but if you don't, then the extra weight and rotating mass can be a waste. I've seen race prepped TH350s laugh at nitrous breathing smallblocks pushing 44s. The aftermarket has enough parts to pretty much make any of the popular GM automatics almost bulletproof.....the TH400 just comes that way from the factory :wink:

The 3.06 first gear in a 700R4 is a wonderful thing compared to the 2.48(?) first of the TH400. It will allow better control and more crawl ratio on the trail, as well as quicker launches. It is also easier to tune the diff ratios for maximum performance. Throw some 4.88:1 diff gears behind a 700R4 and they will feel like 4.11s on the highway because of the overdrive....but they will feel like 5.13s when taking off(compared to the TH400). The only downside to it might be the wide ratio jump between first and second, but that is minor. Most of the bad reputation the 700R4 has is because of the early production models that DID often fail, but the later units are fairly strong.

Advance adapters or Novak is going to be your friend when it comes to bolting it in your Jeep.
 
the 4L60E is ~ as strong as the TH-350, and the 4L80E is ~ as strong as the TH-400 LBR
 

LBR,who makes those? where can I get one? are they expensive? thank you.
 
RE: never again!!!maybe?

the 4L60E is ~ as strong as the TH-350, and the 4L80E is ~ as strong as the TH-400 LBR
Click to expand...

who makes those? where can I get one? are they expensive? thank you.
Click to expand...

The 4L60 and 4L60E(electronic) are revisions of the 700R4. Basically the same goes for the 4L80E, it's an electronically controlled, overdrive equipped TH400.....sort of. I have no experience with one but I've heard that the 4L80E is just as strong as the TH400 as far as torque ratings go, but I doubt adding so much complexity is a good thing as far as strength and reliability are concerned.
 

RE: Re: RE: Re: RE: Yep

The 4L60E & 4L80E transmissions are the new school of electronic transmissions - they are made by GM, you can get one thru the aftermart transmission shops or the wrecking yards out of 2000 something GMs, and they are very expensive to purchase, then you need the stand-alone computer for another 800 or so $....not someting that you need. TH400 is rock strong "out of the box" and Junkpile hit all the specs. and criteria bang on earlier. Another 4 speed auto that was not mentioned is GM's 200 4R which is just as strong as the 700R4 (contrary to belief), but has more of a "close ratio" gearing where the 700 has a "wider ratio" gearing. The 200s got a bad rap the first 3 years they were out because of being a new design and parts failures. GM learned their weak points and then built their 200s stronger and then the 700 followed. But the 200 & 700s are still a bit weaker in stock form than the TH350, and can't hold a candle the the 400. LBR
 
I like the fact that the 700R4 has the lower first gear, but don't like the fact that they aren't as strong. I plan to run 39" boggers, so will this affect the wear on the weaker of the two. I know with meats that big I'll need some LOW gears. Maybe even 5.38. . . It'll be a TRAIL RIG ONLY, I'll build another and another and another and another and so on and so forth. Please also check out my suspension post!
 

Because you mentioned that it will be trail only and can change gearing, you have no reason to need or want (in my opinion) a 200 or 700 - why put a weaker overdrive unit in for trail cruising? Why would you need overdrive for a dedicated off-road vehicle? Are you planning to drive higher speeds and want fuel economy? I guess if you were building for the long, high speed BAJA race, then an overdrive could be used to it's fullest potential.....Use the 400 and then you KNOW that the weakest link in the chain isn't the transmission LBR
 
Nah, I'm not gonna be going over about 15mph on the trail, and even that's pushing it. Is there any way to lower the gears in the TH400? or will it just be easier to go with a set of 5.38's in the axles?
 
LBR said:
Because you mentioned that it will be trail only and can change gearing, you have no reason to need or want (in my opinion) a 200 or 700 - why put a weaker overdrive unit in for trail cruising? Why would you need overdrive for a dedicated off-road vehicle? Are you planning to drive higher speeds and want fuel economy? I guess if you were building for the long, high speed BAJA race, then an overdrive could be used to it's fullest potential.....Use the 400 and then you KNOW that the weakest link in the chain isn't the transmission LBR
Click to expand...

I love the GM 4 speed automatics, but I have to agree.
 

You can change gear ratios in the 400 - involves teardown and assembly of transmission - if you are DIY'n, the front and rear ends with deep gearing (like you had already mentioned) would be simpler to do than the transmission, and cheaper too - I would change the gearing in the diffs. and not even consider the transmission, unless you are going to order the 400 from a hi-performance transmission builder. Then it's like Burger King...You can have it YOUR way. LBR
 
gears it is, what do tou think about 5.38's running 39's, Too steep? or should I just stick with 4.88's? I'll have to do some road driving to get to the trail. but not much.
 
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