th400 or th700?

[PacMan]

Hello

After long time thinking about a replacement for my weak 3.5 carby engine, i am sure i will put a ls1 in my 84 Range Rover.

I want to keep the LT230 and i am not sure what gearbox is the best way to go.

If i am looking for the ratios, the th700 is my choice.

But i read a lot bad stuff about the th700.
- to weak
- bad connection to transfer case
- no space for front drive shaft
- very big at all

Is here somebody with a th700 behind a chevy smallblock?
Can somebody give me some decent information?

Thanks for reading.

Greetings
chris

[stuee]

The th700 the same as the 4l60 (mechanical version). The ls series engines supplied in aus were all tied to some form of 4l6xe transmission (excluding the manuals of course) where the x is 0 or 5. The 4l65e is the pick of the trannies if you can pick one up as it was used in the HSV's before they went to 6spd autos. The biggest pro about it is that it has a five pinion planetary gear set as opposed to three. There are also a host of other stronger features as well.

Any of the 4l6x family can be easily upgraded to handle the power of a stock to very warm ls motor in a 4wd quite easily. It will be easier to get the ls motors to run better with the electrical versions of the trannies too, having better shifting points etc.

But if your not concerned with driveabilty so much or the overdrive then the th400 would be okay. Otherwise stick to the electric version of the th700. If you have deep pockets a 4l80e is a good choice too but heavy and expensive to get the 4wd versions shipped over from the us.

[6.5 rangie]

I had one behind my 308 stroker in my rangie then behind a chev diesel, if you get it built right it will be fine, good for 500hp apparently. Mine was mated to a machined off LT95, but you can get an adapter from someone from here to suit the lt230, but its a wait, i know of someone who ordered one around christmas and i think he is still waiting.

[nottie]

The adapter is from Overkill. They do get alot of work thru there so may take a bit of time. Haultech also do them. PM strangerover if needed.

[6.5 rangie]

yes didn't want to mention names as its not my problemo

[twistylandroverguy]

Over here the 700r4 is the transmission of choice for everything from Jeeps to High horse power hot rods and street driven drag cars. There are a zillion parts suppliers and you can even get a kit to eliminate the electronics in the aforementioned 4L60E if thats an issue. The kit is built by http://www.tcsproducts.com/ in Canada. For the record, a 700R4 is basically a TH350 with an overdrive gear and a lockup torque converter. The 4L60E is a later variation of the 700R4 incorporating electronic control and other mechanical improvements along the way. The 4L80/ 4L80E is a TH400 with an overdrive gear and a lockup torque converter (uses a carbon lining on the pressure plate; indestructable), is very tough AND super heavy. Unless you have more than 400 HP, I'd go with the 700R4. The problem with the tailhousing cracking on the 700R4 is usually caused by mounting a transfer case to it that is significantly heavier than it was designed to carry ( like a NP 205 ). Extending a support bracket back from your crossmember to support the T-Case would certainly help.
Maybe you could fit a 1000 series Allison in there...