[RacinRex]

I know this has been a controversial suject over the past couple of years on the yahoo group. I don't want to open a can of worms, however I see a couple of guys here with swaps well under way or that are already finished that include the 700r4 tranny behind their 4bt.

I want to start this thread to draw up a list of points on including the 700r4in a 4bt swap. It should include sharing of modifications and vendors that can help:

1. How did you address the mating of the Torque converter to the flexplate?
a. modify the mounting points on the torque converter
b. modify the ring on the flexplate?

2. How did you modify the 700r4 to handle the torque of a diesel?

3. Don't 700R4s need vacume to know when to do certian things?

4. How is it holding up to miles and what kinds of abuse are you feeding it?



EDIT:

Pictures, we like pictures of those mods.

 

[52wrench]

I was going with a 700R but decided on a ZF from a "less to go wrong" standpoint. For the TC to flexplate problem I was going to machine an aluminum ring that goes between the TH400 flexplate and the 700 TC. It would bolt to the plate with the 400 bolt circle then have a smaller bolt circle for the 700 TC. The bolts for the 700 would go thru the plate, alum ring, and into the 700 TC. I was going to use a 1200 RPM stall converter. For trans mods, go to www.transmissioncenter.net and then to the 700R4 page. At the bottom there is a table that shows the mods they make for their levels 1- 4 Raptor trans. I was going to build mine to level three. The 700R does not use vacuum, it uses a TV (throttle valve) cable that connects to the throttle lever on the engine. It controls the trans line pressure and it is VERY critical that the proper relationship between TV cable pull distance vs. throttle opening be properly set up. Too little TV cable "pull" distance and the line pressure is too low and you burn up the clutches. Too high a pull distance and the line pressure is too high and you blow the trans pump. Look at the transcenter site and also bowtieoverdrives and you can get a lot of good info on that trans.

 

[RacinRex]

if these guys can put one of these trannys together they should be able to sell a torque converter with a bolt pattern that will bolt up to our specific flexplates. $1995.00 plus 187 for the torque drive package sounds like a good deal to me if it truly can hold the torque this thing will lay down.

 

[Av8r]

Having owned 2 Chevies with 700R4's behind Detroit 6.2 boat-anchors, they will work with a diesel well enough.

I acknowledge the 6.2 is not in the same class as the 4BT(A), but it does prove that the tranny can function behind a diesel.

 

[JBox_Johnny]

i have a cj7 with a 4bt and a 700r4...
not aware of these issues before choosing this transmission...
but while in the process of installing the trans the first problem was mateing the torque converter with the adapter ring...
i just modified the mounting holes with some hardened washers and initally installed standard torque converter bolts....

after about 700miles one of the converter bolts snapped and the others were working thier way out this with locktight.....
after removing the transfer case and retapping the converter holes i installed some hardened studs and tacked them from the converter side and used nylock nuts...

after back together stopped by a trans shop to get some opinions on TV cable setting they said it is really trial and error pretty much what was said here in this thread....

800miles later trans shifts nice and overdrive works well and temps are nominal with a trans cooler and running it through the radiator as well....

so far i am happy with this transmission it works very well; although i am not rock crawling with this trans yet this trans is built to handle more torque than the 4bta in my jeep is going to put out... this project for me is trial and error time will tell for the setup....

if ther are any changes i will post them...
later all hope this helps...
-john

 

[bcowanwheels]

it wont hold up

 

[JBox_Johnny]

do you have any history with this?
not much info?

 

[RacinRex]

Jbox, I'm with you. If somebody comes in and says "won't hold up" they need to provide more detail. The 700r4 got a really bad rap back in the day and the reputation is out there on the surface that these are junk.

However when I'm talking to guys who run them on a daily basis in big block drag cars they tend to know a little bit more. They can talk for an hour or two about the small problems with this tranny and how to address them.

1. install a low stall converter
2. get the tranny built for torque.
3. adjust TV cable propperly
4. install a low rpm governer to get the tranny pumping fluid sooner and shifting at the right rpm range.

among other things these are the basics that I've found on this tranny and making it work with a diesel... but I want these guys who have them to keep us up to date.

 

[JBox_Johnny]

I had my tranny build by mad dog transmissions in fla...
you can look them up on ebay they had good feedback and seemed to know what they were talking about i told them the torque range and the hp range along with the horse power...
my seem to shift well and i think i have the tv cable set right, like i said before the tranny shops around here seem to help a little, and a little bit of reading up on them we will see...
later jbox

 

[Diesel Durango]

well, i'm having an adapter ring made up to bolt up my converter to my engine. I will be using all metric hardware with nylock nuts and plenty of red loctite to hold it all together. I don't like the idea of having extra bolts in there, but hopefully i won't have any problems.

The main reason i am doing this as opposed to having a custom converter made up is because I plan on replacing the 700r4 that i have right now. it's an early model with a 27spline input. I would just make an initial investment in a nice converter, but if i build up a new transmission, i will use a 30 spline model and the converter will be useless. This is just a temporary solution that may work out. if it works out, i may keep it. we'll see.

The ring will be 1/4" steel and is going to cost me $55 shipped. If anyone is interested, i can get you contact information. You can also wait to see how i come out, that shouldn't be alll that far down the road.

 

[RacinRex]

Diesel Durango,

I'd like to know where you got the ring, please PM to me or email the information.

I'm also very anxious to see how your old 700r4 holds up those older ones, sub 1987 are famous boat anchors.

Jbox... I looked at Mad Dog and did some research over in thirdgen.org (an old camaro stomping grounds of mine). Lou has managed to make a bad name for himself over there. I hope yours is one of the exceptions. A couple of the tranny gurus on that board tore apart Mad Dog built 700r4s and there wasn't much good said. Most that have them are not happy. I'm not trying to dis-hearten you or bad mouth your tranny I'm just trying to share information that I gathered.

 

[JBox_Johnny]

man that sucks for me....crybaby crybaby
his feed back looked ok....
thanks for the info i will be in contact if anything goes wrong...
i won't be happy if this tranny dosen't hold....
so far it is working fine....

 

[BioBusGroup]

The ring will be 1/4" steel and is going to cost me $55 shipped. If anyone is interested, i can get you contact information. You can also wait to see how i come out, that shouldn't be alll that far down the road.

How are you going to accommodate the 1/4" difference? Are you going to cut the converter posts down 1/4"? Please email me the contact info, I would rather do the same since I have two converters to test and swap. Sorry to hear that you have the old 27 spline. I picked up one of those as well before I did more research. I was able to sell it and pick up another 30 spline via craigslist.org. If you are near a populated area you may want to try the same.

 

[JBox_Johnny]

i'm checking around and contacting the past buyers of these trans....one guy said his is working fine but it is not a daily driver....
i've sent out about 20 emails we will se what happens...
later
there is about a 1/4 inch between the converter and the adapter ring but thats about all until i bring it together, on mine anyway.
that ring sounds like a good idea i woul like to know how it works out?

 

[Diesel Durango]

here is the ring:

as to the 1/4", i was pretty sure there would be that much play that it would work. Am i wrong? I hope not. anyone know if i'm way off here? should i have it made out of 1/8" as well? would 1/8" be strong enough? I would think so, but i'm not an ME.

 

[RacinRex]

is this something this company makes on a regular basis?

 

[Diesel Durango]

no, this is a custom piece that i drew up.

They said they will keep it on file if anyone else is interested in one down the road. That is if it works for me.

 

[Diesel Durango]

Alright, I think i have answered the converter spacing question.

here are some pictures of my trans/conveter bolted up:

The second picture shows a piece of 1/8" steel fitting easily in between the two.

I think i'm just going to go with 1/8" I don't think strength will be an issue. This does mean that there won't be much play between the converter and the transmission though. Does anyone know that this will or won't be a problem? I can always grind/mill down the pads or something.

 

[JAFO]

is that a mod 700r4 TqCon, or stock?

 

[Diesel Durango]

at some point the trans was rebuilt and i'm guessing that's a newer converter.