Topic: Whats the best way to go after a chevy vortec 4.3 swap??? Meaning trans and case

[Thomas P]

Im thinking about the swap on my 1985 crawler.  I may be getting a 2000 Astro van with 80k miles for the swap. I want power and one tons, but what about tranny an t-cases? What is the ultimate setup? I have 21 spline dual ultimates but I know they will have to go. Im just starting to research this, thanks guys!

[4RunnerChevy]

I know quite a few people who did this swap and retained their toy boxes.  I would go with a tranny that was offered for that year 4.3.   You can keep your toy boxes, maybe upgrade them a little, and get an adapter.  Ask around, check the PBB faq sheet on the swap.

[Thomas P [OP]]

i have an adapter and a 4.7 gearset, but im thinkin about 49 IROKS, gotta beef things up, im researching building a 23 spline set of cases VS an atlas...... Anyone have an opinion on these?

[Thomas P [OP]]

this thing is going to be a snow monster

[bigarms23]

if  your going with 49s than i would use the 4.3 with tranny and go with an atlas

[Thomas P [OP]]

you mean a chevy tranny right? i wont have a chevy tranny but will find one, i have w56 and whatever comes with the astro van

[superyota]

i have a buddy with a yj with a 4.3 and a 700r4 on 60's front and rear running 39.5's.  he ran a 21 spline tcase for a while, then downgraded to a 4spd atlas that blew up 3 times on him.  now he has a 2 speed atlas while aa is working on redesigning the 4spd.  every now and then he makes a comment on how he should of stuck with the toy tcase and doubled it up.  I think the toy tcase will hold up fine.  i'm putting my buddies toy case behind my buggy with a tbi 350 and 700r4 on 60/14 with 39'5's.  for the tranny, i would go either 4l60e(or 4l65e if you know a good builder) or go with a 700r4.  turbo 350's and 400's are great, but 1st gear isn't so low.  just my  

[yota_krawler]

Sm465 4 speed granny low, with a 203, 205 or dana 300. The sm465 bolts right up to the 4.3, the 4.3 shares the same pattern as a 350. So any tranny that came with the 350 will bolt right up. It's basically a 350 with 2 less cylinders. 21 spline will not hold up, 23 spline might. AA makes an adapter to run a r150f, you could do 23 spline duals. I wouldn't want an auto. Not good for snow IMO.

[yota_krawler]

If your going that route why not just do a small block v8? 327, 350 etc. A 4.3 with 1 tons and 49s will still be under powered.

[Thomas P [OP]]

Mike trying to talk me into 47 iroks, still debating asa far as a small block vs a v6 i have a donor lined up.... and i already have a yota with a 4.3 for a work truckm and it would be cool to have one in my crawler as well.... Also think i wanna ditch my dual ultimate 21 spline and do 23 spline dual ultimates, i just have to pick the tranny now, im scared abot going auto but i want the strongest setup, anyone have any input on toy vs chevy trannies on strength?

[topar]

I run a 350, turbo 400 (Auto) & Dana 20, pretty much the same as a Dana 300 & both cases can be twin sticked for less than $50.  I like the auto tranny mostly because I don't like the hassle of a stick anymore.  If I was doing it over I would go with a 203-205 doubler my front drive shaft is short & at a bad angle the doubler would give it more length.  I am not sure about the strength of a toy tranny & t case behind the 4.3 or V-8 especially with those size tires.

[yota_krawler]

Sm465! Beef! It's the same tranny as a nv4500. Nv4500 has a 5th gear tho. They are used in diesel trucks...

[THK Matt]

that astro will have a 4L60e, which is a modern version of the 700r4

[Thomas P [OP]]

Wonder if I should run the 4l60e?

[superyota]

4l60e is a good tranny.  and a good builder can build it up to a 4l65e which is even better. 

[THK Matt]

all of the 4.3L Vortecs will have a 700r4 behind them from 86-95 and a 4L60/4L60e from 96+.
correct me if im wrong on that, but thats what I have gathered.

I am going to run a 5.7L, 700r4 and an NP241 with a D60 and 14B
I say run the stock trans and beef up your toy duals. its a $560 adaptor from AA to bolt those tcases up. cheaper then doin an atlas and your lower geared and more gear options

[superyota]

all of the 4.3L Vortecs will have a 700r4 behind them from 86-95 and a 4L60/4L60e from 96+.
correct me if im wrong on that, but thats what I have gathered.

I am going to run a 5.7L, 700r4 and an NP241 with a D60 and 14B
I say run the stock trans and beef up your toy duals. its a $560 adaptor from AA to bolt those tcases up. cheaper then doin an atlas and your lower geared and more gear options

your running the identical setup i have in my buggy right now.  have you clocked your np241?  the reason i'm looking and going to toyota case is more ground clearance.  the 241 hangs down really low. 

the 95 4l60e is a year specific tranny.  to make it work, you have a 95 ecu to run it.  no other year will run it but a 95.  just a little info.

[yota_krawler]

Thomas, why do you want auto? The 4l60e is an s10 tranny... You think it would even possible hold up to anything over a 42"? Being easy on it?

I don't think one ton axles will hold up to a 49" that is a huge tire. To run a 49 IMO you would need a 5.3 at the least, then a bullet proof tranny and a atlas, 2 1/2 ton rock wells. Full hydro and then it wouldn't fit on your flat bed trailer. My truck won't even fit.

[superyota]

personally, i like manual.  the buggy i'm building is for my wife, and she prefers auto. 

[THK Matt]

your running the identical setup i have in my buggy right now.  have you clocked your np241?  the reason i'm looking and going to toyota case is more ground clearance.  the 241 hangs down really low. 

the 95 4l60e is a year specific tranny.  to make it work, you have a 95 ecu to run it.  no other year will run it but a 95.  just a little info.

i dont have any of it yet. we'll see what deals i come across.
I wanted to do a D300 or NP241. it needs to be driver drop for the Ford HP D60 i am going to run. the HP D44 i have now, i want to sell and upgrade to the D60.

and why does he have to run 2.5ton rockwells for a 49? Infernal runs 47s on his 1tons with a 2.7L 3rz.

[superyota]

?  I don't see any need for 2.5 tons for 49's.  I had 49's on my buggy for almost a year.  all it ever saw was snow though.  the 49's are gone, and now i have 39.5's.  i'll eventually get rid of my 39's and go with either 42's or 44's.  the 49's were nice, but just too big for the trailer i run.  unless your wheeling a 6000# truck through hammers, i don't see any need for 2.5 tons. just my 2 cents.

[yota_krawler]

Where did you get 47s? He just got 43s... Anyway. Run what you want.

Hell you can throw 46s on a Dana44. Smart no.... People do it

[superyota]

Thomas, why do you want auto? The 4l60e is an s10 tranny... You think it would even possible hold up to anything over a 42"? Being easy on it?

I don't think one ton axles will hold up to a 49" that is a huge tire. To run a 49 IMO you would need a 5.3 at the least, then a bullet proof tranny and a atlas, 2 1/2 ton rock wells. Full hydro and then it wouldn't fit on your flat bed trailer. My truck won't even fit.

4L60E is an s10 tranny, along with any other 4.8, 5.3, or 5.7, and even some of the 6.0 ss trucks. all chevy truck, van, camero, etc. that came with a v8 have a 4l60e.  The only ones that came with a bigger tranny are the 2500 and 3500 trucks that came with either the 4L80E or the Alison.  they hold up just fine IF they have the right mods done.

[Thomas P [OP]]

i drive mellow, look at my rig right now, 42's on toy axles.... I will be fine with 47's or 49's on fully built tons, im just worried about the trans and cases, ive been researching the Atlas and think im over it, might try and build 23 splines using marlins chromo stuff......