700R4 Tranny Source (1 Viewer)

[sjpitts]

I am considering putting a 700R4 in my FJ55. I currently have a turbo350, and I am going to be putting in a 203 doubler/split t-case-- and I am seriously considering moving to a 700R4 at the same time.

Anybody know of a good source? I would like a rebuilder that knows how to make a good truck transmission without huge costs.

I am also going to need a new output shaft, but that might only be available from Advanced Adapters.

Thanks

Jared

 

[RUSH55]

Hey Pitts, what do you need a doubler for if you have an auto? ???
I don't have any 700r4's but I'm sure you could call around to some scrap yards, should be plenty of 'em. I know a guy up here that does rebuilds on autos, but Cottonwood might be a little out of your way. The downside to having a private guy do the rebuild is that there's no warranty, while shops usually have one. Auto's shouldn't be that much more to o-haul, costwise, than manuals, but I was quoted at about $500 for a rebuild of an SM 420 - just labor.

 

[RUSH55]

Oh, BTW, what engine are you running?

 

[sjpitts]

I am running a chevy small block 350. Quadrajet. Nothing fancy.

I am doing the doubler because I wanted a toyota T-case and it was not going to any more money to do it with a doubler. I will have to explain that.

Basically, my 55 when purchased 9 years ago had a complete GM driveline installed by the PO. GM 350 engine/turbo350 tranny /NP203 t-case. The NP203 has always bugged me, it is a big brute of chain driven thing, and more importantly, has a centered output, while my rear end (from an FJ60) is offset. So for years I planned on replacing the 203 with a toyota case.

Well, then Jerry Nichols came out with his adapter to use a 203 doubler with a split (FJ60) t-case. I already had a 203, so it was just as easy to get an adapter between the 203 gear reduction box and a split t-case as it would be to get a regular toyota t-case adapter. All I need to do is replace the back end of the 203 with the adapater and the split t-case.

Basically, I needed to buy an adapter either way, so why not buy that one that gives me a doubler?

I don't know if I will get any additional performance having the doubler with an automatic, although it really seems like it would help on the down hill sides. I currently have 33 inch tires and 3.70 gears, so having the extra double might help there as well.

My split t-case is getting rebuilt and it should all be ready to go in within a couple of weeks.

I have been really torn on the transmission issue. Part of me just wants to keep the T350 for the simplicity of it. Part of me wants a 700R4 for the overdrive (which would be better if I went with 4.11's-- another thing I have been considering for a long time)

I have got a week or so to decide this, and I will probably decide based on what a 700R4 with the appropriate output shaft would end up costing me.

Jared

 

[LandCruiserPhil]

Jared Im pretty sure that the 700r/4l60 and the 350 bolt pattern is the same the 700r/4l60 has a longer output shaft that can be cut.

The 700r/4l60 Has lockup = better mileage
30% overdrive
700r/4l60 first gear 3.06 - 350 Turbo 2.52

I run a GM overdrive trans in my 40 and 60 and love-it

Phil

 

[sjpitts]

Phil

Where did you get your trannies? Are you running 700R4's or later models?

Jared

 

[LandCruiserPhil]

My 40 is a 4l60 it was with the engine and rebuilt
My 60 is a 700r was with the engine 500 mile when it was converted

Phil

 

[sjpitts]

Phil and others

Maybe you can help me know what to look for in a 700R4.

I know that I will need to get the shorter output shaft (to mimic a turbo 350) but other than that I don't really know what to look for. I want to be able to tow my little boat with confidence, and I want a good tranny, but I don't want to pay an extreme amount if I don't have to.

I know the trannys come with different torque converters with different stall ratings. What should I get?

I also know that later models are better, but I am not sure if this applies to rebuilt units.

I also know that some rebuilders advertised "improved clutches" and stuff like that, but again, I don't understand the details.

One more thing. I am a little unsure as to what the different type of valve bodies are. I want the kind that will automatically shift in drive, but that when put in first will stay in first (for better engine braking). This is the way my turbo350 works. What do they call that? I think it might be "manual valve body" but I am not really sure.

Any other advice would certainly be appreciated.

Jared

 

[hj60]

You seem to want a manual valve body.
I recommend a clutch pack upgrade. This basically entails thicker friction
material or more friction discs per pack. Depends on the kit.
Your torque converter should have a stall speed 50 - 75% of your redline.
Ideally just above peak torque of your engine.
The tranny doesn't "come with" a converter. It's like a clutch. You buy it to
match your trans/engine. Although nowadays, it's treated as part of a
rebuild kit for a tranny.
You may also want to look into a unit with a "GM torque converter clutch".
It's like a 2nd overdrive. Saves on gas. But it's also more parts to go bad.
The earlier 700s had issues, but most can be overcome with a good rebuild
and the above-mentioned upgrades. Newer is better, but with the
abundance in junkyards of rebuildable cores, I wouldn't bother.
This is my opinion. I'm not an auto tranny tech, just somewhat familiar.
Hope this helps.

 

[sjpitts]

Are you sure that is what "manual valve body" means?

I have seen different people say different things when it comes to a defination of those words. Like I said, I want it to shift like an auto when in drive, but I want it to stay in first when I put it there. That is how my TH350 operates.

I think, but don't know, that some valve bodies dont auto shift at all. Not sure what they call that.

Jared

 

[hj60]

[quote author=sjpitts link=board=27;threadid=14686;start=msg139085#msg139085 date=1081967303]
Are you sure that is what "manual valve body" means?
[/quote]

A manual valve body shifts hydraulicly, with no computer/electronic controls.
That's pretty much all it means. It'll still shift through all the gears in "D".