Author Topic: sm465 to 700r4 swap  (Read 8496 times)

Offline ajdmello

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sm465 to 700r4 swap
« on: September 24, 2015, 05:57:59 PM »
I'm just wondering what will be involved in swapping my tranny? I have a 208 tcase. I was told that the splines are different on the input shaft of the tcase is this true?

Offline roundhouse

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Re: sm465 to 700r4 swap
« Reply #1 on: September 24, 2015, 07:36:06 PM »
Depending on the year of your Trans
The splines will be 15 i think or 27

I think the 700 has 27

Easiest thing to do is buy a 700/208 already bolted together
Matching splines and intermediate housings can be frustrating


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Offline enaberif

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Re: sm465 to 700r4 swap
« Reply #2 on: September 24, 2015, 07:38:58 PM »
SM465 is either 10 or 32 spline depending on the year of the transmission.

Offline 1967KaiserM715

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Re: sm465 to 700r4 swap
« Reply #3 on: September 24, 2015, 09:18:59 PM »
Going the other way with mine, I can tell you can't reuse adapter, transfer and in some rare cases crossmember. Sm465 is 10 or 32spline( I am pretty sure all 208 mated to sm465 are 32 spline) 700r4 is 27 spline

But you can reuse driveshafts, the adapter between tranny and transfer ends up making lengths the same
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Offline Irish_Alley

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Re: sm465 to 700r4 swap
« Reply #4 on: September 25, 2015, 07:18:22 AM »
the sm465 was 10 spline till 81 where it changed to 32. the 700r4 is 27 splines, imo if you dont have a 700r4 all ready is to buy a junked truck with the same bed length as yours and get all the parts you need off it (drive shafts, cross member and throttle brackets). but be warned the 700r4 is a week trans and is known for problems so you might be buying a bad trans or one that has little life left. then you will spend 5-700 to get it rebuilt, might be able to buy a newly rebuilt one for about that price. also if someone doesnt adjust the tv cable then it can and will burn the trans up within 15 miles.
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Offline ajdmello

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Re: sm465 to 700r4 swap
« Reply #5 on: September 25, 2015, 06:41:44 PM »
OK thanks guys that's what I needed to know. Its a 86 guess I forgot to say that.  Sure would be great to pick one up that's already bolted together!

Irish- I have heard that it is a weaker trans. I would love to put in a 5 speed but seems like that's gonna cost quite a bit more is the problem. And turbo350 or 400 don't have the overdrive I guess that's why I was thinking the 700. The truck will be a DD when im done with it.  I do have a buddy that can rebuild them so hoping to find one that junk and just have a whole rebuilt done. not sure what the kit will cost me though. should a rebuilt 700 hold up behind a stock(for now probably a cam or other minor upgrades down the road) 350tbi and 4inch of lift with 35s?

Offline roundhouse

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Re: sm465 to 700r4 swap
« Reply #6 on: September 25, 2015, 07:49:15 PM »
We ditched the 465 for a NV3500 5speed

It's a bolt in swap but you have to use a 32 spline t case




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Offline Irish_Alley

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Re: sm465 to 700r4 swap
« Reply #7 on: September 25, 2015, 11:42:16 PM »
I've seen ones last and I've seen ones fail behind a 4.3. When I was looking for a 4l80 I wanted one that was burnt up so I would only have to pay a core charge on it.
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Offline ajdmello

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Re: sm465 to 700r4 swap
« Reply #8 on: September 26, 2015, 08:52:39 AM »
Well I hope mine holds up! Lol.


Roundhouse- what did you do for your clutch? And what year transmissions will work 88 up? I ready somewhere about getting a different bellhouseing and the clutch lines being different

Offline roundhouse

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sm465 to 700r4 swap
« Reply #9 on: September 26, 2015, 12:56:51 PM »
Well I hope mine holds up! Lol.


Roundhouse- what did you do for your clutch? And what year transmissions will work 88 up? I ready somewhere about getting a different bellhouseing and the clutch lines being different
The 97-07 3500s are stronger
Think we used the same clutch as with the 465

We used the 3500.  The Trans from 1/2 ton it has a fixed bell housing

The 3500 has an internal slave cylinder and we just used a 87-91 master and drilled a hole in the existing clutch pedal to bolt the master cyl rod to



Lot of people use the 4500.  Because they are stronger But we didn't want a slow shifting truck transmission


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Offline ajdmello

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Re: sm465 to 700r4 swap
« Reply #10 on: September 26, 2015, 03:06:04 PM »
Round house- that's what my problem was that and I want that extra gear! I'll definitely  look in to that! How much will that transmission cost me? So what bell house do I use? You have any pics of the set up?

Offline ajdmello

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Re: sm465 to 700r4 swap
« Reply #11 on: September 27, 2015, 07:40:29 AM »
Well I hope mine holds up! Lol.
 


I know it's not a 1 ton but would something like this work? https://lansing.craigslist.org/cto/5234735377.html
Roundhouse- what did you do for your clutch? And what year transmissions will work 88 up? I ready somewhere about getting a different bellhouseing and the clutch lines being different
The 97-07 3500s are stronger
Think we used the same clutch as with the 465

We used the 3500.  The Trans from 1/2 ton it has a fixed bell housing

The 3500 has an internal slave cylinder and we just used a 87-91 master and drilled a hole in the existing clutch pedal to bolt the master cyl rod to



Lot of people use the 4500.  Because they are stronger But we didn't want a slow shifting truck transmission


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Offline frotosride

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Re: sm465 to 700r4 swap
« Reply #12 on: September 27, 2015, 10:06:24 AM »
should a rebuilt 700 hold up behind a stock(for now probably a cam or other minor upgrades down the road) 350tbi and 4inch of lift with 35s?

Yes... OE 700r4 170k original miles and still tucking!! I'd say a fresh one will hold up if its done right as with anything.
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Offline roundhouse

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sm465 to 700r4 swap
« Reply #13 on: September 27, 2015, 11:01:30 PM »
Round house- that's what my problem was that and I want that extra gear! I'll definitely  look in to that! How much will that transmission cost me? So what bell house do I use? You have any pics of the set up?
we found the Trans on car-part.com
Search for 97-07 manual 4WD Silverado Trans

We paid $600 for the Trans
Pretty sure we used the same clutch as stock
Bell housing on the GM 3500 is made to the Trans and bolts to any small block Chevy
One bolt won't match up , no biggie as long as the rest are tight
You have to use a 32 spline NP -208 with the 6 bolt round bolt pattern from behind a TH-400
You don't use any intermediate housing
When you're searching for that , don't tell the seller how many splines you need , they will lie and tell you whatever you want to hear hoping you'll hand over the cash without counting the splines Yourself ,
And claim they thought you were talking about the exit splines on the output shaft for the driveshaft

ask the seller to count the splines and call you back
Easier thing is to find one from someone parting out a CUCV army pickup
They all had TH -400 /NP-208.   And grab the cross member too
You'll need it and it bolts right in slightly further back , the front holes on the crossmember match up to the rear holes in the frame , so you just bolt that in and drill two new holes in the frame

But again , sellers either have no clue what they have or lie, I drove 2 hours to get a NP-208 from an army pickup , that was a NP-203

Silly me, I could have asked for him to text me a picture .

Converting your clutch pedal to use a hydraulic master cylinder is the hardest part

Just measure the travel in the new master cyl
remove the old rod and use a tape measure to find the location on the pedal that gives you that length travel

Unless you find a deal on a 87-91 hyd pedal setup.  But most people want $300-350 for it



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« Last Edit: September 27, 2015, 11:05:59 PM by roundhouse »