What to run behind a 700r4?

[wtmtnterror]

Just looking for some ideas on what t-case to use in my 40. I was looking at using the original case, but the adapter to the tranny is around 700 from AA. Plus another 200 for a rebuild kit for the tcase. So would I be better off looking for a different tcase and what could I expect to pay vs. the 900 to get the lc case in there?

 

[Niner]

limited choices unless you go to a centered rear diff.

 

[woody]

you have a few options....

1> adapt to the stock case
2> adapt to a stronger split 60/62 case
3> adapt to a stronger/deeper Orion case
3> adapt to a D300/atlas case AND install a centered rear diff
4> Marlin doubler to the stock/split/orion case

Hate to say it, but the cost to the stock case with a rebuild is cheapest, but also weakest. Honestly, the words "automatic" and "cheap" shouldn't be used in a sentence...

I did the 700 to a Sunray adapter to a built D300 (4:1 and 32-spline), plus a 2-piece front d-shaft and a home-made hybred centered rear axle. $1k for the built 700, $450 for the adapter, $1550 for the D300, $800 for shafts, $200 for the rear axle....VERY rounded numbers, but there's a fast $4k right there...

If it were me, I'd spend the $900 now, expect that to go up 50%+ before it's actually done, and drop in an Orion later in life for the strength/range gains. At least then the Orion is a bolt-in.


edit:
oh yeah...add in a tranny cooler for $200...mounts and brackets and bushings and such for another $200....

And I assume labor is free....and 3-4 months of downtime is free too....

betcha I could find a fast $5k in receipts....uugh....however, it HAS proven to be a very strong driveline, and I wouldn't change a thing

(here's hopin for a mod-free winter this year tho....lol)

 

[tornadoalleycruiser]

Or 700r4 to 203 to whatever case is another option.. You'd get a cheaper doubler in there and it's about the same length as the AA adapter to whatever tcase you want (cruiser case). the 203 adapter to Tcase is made in 10/16/19 spline Cruiser cases.
Haveing helped build a ton of different options your pretty much unlimmited in what you can do. If you want stock cruiser case look at the 203 to cruiser case and compare the cost to the AA spud shaft one and see what gets you where. if you want centered rear axle then you gotta whole nother can of worms

 

[woody]

good call...I forgot about a 203 doubler option....

only bad is the weight....and the 203 is one phat hog....

to keep the strength, I'd look at the 203 doubler to a split case....IMO, the stocker isn't up to that much gearing drop....or, not how I drive anyways...

 

[Eskimo]

You forgot the $200 shifter...

Honestly, centering the diff opens you up for a ton of additional options, and you get a strength increase, and lose the c-clips...

I've got a minitruck t-case with 4.7's behind my 700, because that was the deal. I don't know that I'd do it again.. the toy case hangs pretty low, and can't be clocked. other than the clearance, I like it.

 

[tornadoalleycruiser]

I had a mini 4.7 behind my 700r4 between my 700 and my splitcase.. It was wicked low.. Scrared the crud outta me.. Swapped it to the 2.28 but that was a doubler.. Your talking jsut the 4.7.. Don't go toooo low with an auto or your truck won't stop! ..

And I agree with Brian.. If your going doubler you wanna strong tcase.. I've used an FJ60 and FJ62 case and beat the snot outta both without issues.. THey're both considered a "split" case and stronger than most cases. Most cases are normally the 3 or 4 speed cases.. 3speed cases are 10 spline, 4speed cases are 16 spline and "Split" cases are 19 spline.

the 203 to splitcase I've helped instal 2, they're great easy instal, strong, 203's are cheap.. I"m a pimper of toyboxes normally but if you want a cheap doubler it's probalby the 203..

and gettin rid of c-clips.. anyone know if pigs working on an eliminator in his new rears for a 40 and 60?

 

[Mace]

Atlas

 

[wtmtnterror]

Thanks for the input guys, I like the idea of a bolt in for the Orion down the road, so I may just fork over the cash for the adapter now and put the stock case back in for now

 

[cruiserrg]

Or 700r4 to 203 to whatever case is another option.. You'd get a cheaper doubler in there and it's about the same length as the AA adapter to whatever tcase you want (cruiser case). the 203 adapter to Tcase is made in 10/16/19 spline Cruiser cases.
Haveing helped build a ton of different options your pretty much unlimmited in what you can do. If you want stock cruiser case look at the 203 to cruiser case and compare the cost to the AA spud shaft one and see what gets you where. if you want centered rear axle then you gotta whole nother can of worms

Just a note, the NP203 to 700r4 was not stock and requires a new trans output shaft to use the factory th350 to NP203 adapter, or the other option is to use a NP241 style adapter and modify to fit a NP203 to use the factory 700R4 output (this adapter is about 3.5" longer that the narrow th350/NP203 adapter).

 

[Niner]

Just a note, the NP203 to 700r4 was not stock and requires a new trans output shaft to use the factory th350 to NP203 adapter, or the other option is to use a NP241 style adapter and modify to fit a NP203 to use the factory 700R4 output (this adapter is about 3.5" longer that the narrow th350/NP203 adapter).

Wouldn't a TH400 to 203 be the same as the 700? I thought they were similiar.

 

[cruiserrg]

Wouldn't a TH400 to 203 be the same as the 700? I thought they were similiar.

TH400 version of the NP203 is 32 spline input, and much harder to find than a th350 version 27 spline. I am not certian on the differences in output shaft length between the 400 and 700 by fairly sure they are different. Lastly the 700 uses a 4 bolt patter on the tranny case where the 400 is the full round 6 bolt pattern...so no bolty uppy.

I "may" work (going on theory since I have never done) but you could try a 700r4 to NP241 adapter (4 bolt to 6), with a th400 version of the NP203, and change the input gear to the 27 spline one from a th350 NP203....but again not sure on the width of the th400 adapter for the NP203 and if it would work right.

note: from http://www.offroaddesign.com/catalog/doubler.htm there looks to be that the 400 to NP203 is about 1/2" thicker than the th350 version....so it is actually easier to use the NP241/208 adatper that came on a 700 and modify the NP203 case and the adapter to make work (I have done this)

 

[Niner]

Gumby should have the adaptor info since I sold him the TH400 and 203 I had

 

[Gumby]

Yup. I did all that research. If you do some Google searching it's all out there somewhere.

I used the AA plate adapter from the 203 to the cruiser case. With the 400 it was easy because niner's trans was already bolted up to the 203. You could do the same with a Th350.

I think Cruiserrg is right, you can adapt a one of the other Gm transfer case adapters pretty easily, but you need to change output shafts.

You could also check with AA and see if they make an adapter from the Th700R4 to a NP203.

 

[HI^C]

damn missed a good one, anyways a bit late.

700 to 208 adapter is a more popular adapter to use.
drill and tap the 203 face.
BTW there is a spacer you can use to run a stock th350 adapter on the 700r4.

range boxes are the same, inputs are different.
400 is 32
700r4/th350 is 27
465 is 10 or aftermarket short 32
c6 is 31
dodge 29 or 23
etc.....
I am about 100% sure the input bearings are the same, tossed out the dodge and ford stuff i had, i will look at the extra inputs i have laying around.

th350 to 203
th400 to 203 adapters are same length more less, tiny differences.

know a good machine shop? make your own adapter. two plates and a chunk of tube.
probably one of the easier ones to get done.

 

[Scottb]

I have what you need, A centered Fj40 rear diff.
I would then use a NP241 T-case, they have a 2.72:1 low range, and then you can get the super short shaft kit from(http://www.jbconversions.com/) and it shaves 6 or 9 inches off the tall housing.
You can get the 241 tcase out of chevys and dodges all over, and you can get them for a good price, and they are strong.