I currently have a th400 and np205 in my toyota behind a small block. It is too high geared and a little too long for my short bed 94. My rear driveline is pretty steep. I am thinking of going to a GM 4-speed with the granny low. I think it might kill two birds with one stone. How much shorter is the 4-speed than a th400?

well if you want a granny low 4 speed, then your lookin at the sm420 or sm465. i have a sm465 and i know that its probly a little more than half the length of a th400, thats just the tranny, add the bellhousing and you might be looking at around the same length, im sure some one knows

The length of a TH400 with Tcase is about the same as a 465 with bellhousing, adapter and Tcase. The 465 to 205 adapter is about 7" long. The concept behind many of the trannys/adapters appears to be to keep the Tcase in the same location whether it is an auto or manual tranny. This apprears true for the 465/203 combo as well. Sorry to be the bearer of bad news:(

So you think the manual and auto will be the same length overall? That sucks. I think I will be looking into it anyway just for the lower gearing.

Off the top of my head - the 465 is 12.5", the adapter is 6.75", and the bellhousing is 6"(?) which totals 25". IIRC, the TH400 is 24.5". If you want some serious low gearing, you might look into a 465 with 203 doubler in front of a 205:idea:

Originally posted by KrustyKruiser
Off the top of my head - the 465 is 12.5", the adapter is 6.75", and the bellhousing is 6"(?) which totals 25". IIRC, the TH400 is 24.5". If you want some serious low gearing, you might look into a 465 with 203 doubler in front of a 205:idea:


But does that take into account the adapter for the 400/205? I don't see how the 4 speed could be as long.

The TH400 bolts directly to the 205 - no adapter - there is a hexagonal (?) flange with 6 bolts that mates to the 205.

As I said above - I think the idea was to keep the Tcase in the same location whether it is a manual or auto tranny - that makes drive shafts, tcase support brackets, shifter, etc all the same

http://wsphotofews.excite.com/026/Dr/aL/m9/eQ26711.jpg

kinda blows the no adapter theory to shit. sorry never had an auto but i am with you in that they are way longer

ok,
it is dark and raining out but i crawled under my chev with a tape.
looks about 38" from block to centre of u joint.
post what your auto is as i am now curious :question:

Originally posted by mj
ok,
it is dark and raining out but i crawled under my chev with a tape.
looks about 38" from block to centre of u joint.
post what your auto is as i am now curious :question: Sorry about the no adapter post - what was I thinking! Doh!

FWIW, the bell housing is 7.5", the 465 is 12.5", and the 465/205 adapter is 6.75" - that totals 26.75". IIRC the TH400 is 24" - and the adapter looks pretty short - whats the guess it is about 3".

Believe me, I hope I am wrong on the auto drivetrain being longer than the manual drivetrain. But I was trying to figure out why Chevy would put such a long adapter between the 465 and 205 - it's not necessary - only from a drivetrain equalizing standpoint.

OK - here's a link to an article I found searching via Google :

http://www.geocities.com/spencerhut/truck/trans_swap.htm

Please note Item 18 where the guy doing the swap comments that no driveline mods were necessary as the difference in tranny length is taken up by the adapter.

I just did the swap from 350TH to sm465, the transfer was in same location. If you do this swap, I made my clutch linkage hydraulic. I used a master cylinder/slave setup from a 93-93 chevy truck, and made a bracket to hold the slave cylinder. Might make your swap easier. I've got $23.95 in my hydraulic setup. I just did it a few days ago, I'll send some pics soon. Tommy

what means "IIRC"?

Originally posted by mj
what means "IIRC"?

IIRC = If I Recall Correctly

You should end up about 3" shorter with the SM465/205 combo. The TH350 and SM465 both worked out the same length, and the TH400 is a little longer. Most of the time 3" will help but not huge.
Your effective gearing won't change a lot with the manual swap, the torque converter does add some gear ratio, so don't just look at the mechanical gears in the TH400 and assume it's really high geared.
If you do decide to swap, check on your options carefully, I think we might be able to keep your 32 spline 205 with the manual trans.
You could go with a 465 or TH350 with a Doubler kit and be about 3" longer than you are right now and have plenty low gears for just about anything.

I have taken out my 350/205 and installed a 465/205 and used the same drivehaft/X- member.....I kept it in until I blew out my spider gears in my Dana 60 FF (Drag Racing). I got a "Digger" tranny in it now....BAD ASS TRANNY!! But I don't see no more than 4-6 in. between all 3 in length......:beer: :D

what is a digger tranny?

Originally posted by mj
what is a digger tranny?

The tranny is built for me "custom" by the same guy "Grave Digger" uses to build their trannies. This 350 tranny has extra clutches in 1st/2nd for "holding power". He even put TCI heat treated shafts in it as well as a Turbo 400 "sprag" for more torque transfer to ground. It also has a "reverse manual valve body" so I can shift when I want to. He even makes a "internal case server" just in case it blows apart in my CRAZY RPM RANTS...:D I think it has everything possible in it you can do.....he also built my 400 trans for my BIG BIG 93 with a 454.....gotta go work on my next "project"......C YA:beer: :beer:

well i think i have managed to fuck the hell out of my th350 in my yota..so what should i do, i want to throwin a sm465 but i cant do it myself. so if i find all the parts how much is it gonna cost ot get the convewrsion done?? whadya think??

what about going to a 700R4 it has low 1st

if you want a hydraulic clutch you can use a bellhousing from '91 blazer(or around there) they have the drivers side mount already on there for the slave cylinder.

Only downfall is the bellhousing is aluminum. Anybody know of a steel replacement?

85+ pickups use that bellhousing as well

Originally posted by Chet
if you want a hydraulic clutch you can use a bellhousing from '91 blazer(or around there) they have the drivers side mount already on there for the slave cylinder.

Only downfall is the bellhousing is aluminum. Anybody know of a steel replacement?

Yes there is a steel 465 bellhousing - I dont know the production years, but I think it was the 1970's. The aluminum one suck - they crack easily - just changed mine out from alum to steel. I got mine when I bought a parts rig - the fella selling it said "you might as well take this old tranny with you" (it was sitting next to the rig. It was a 465 and steel bellhousing!

how did you crack a bellhousing?

Originally posted by mj
how did you crack a bellhousing?

Dunno - they just dont like the stress of wheeling?:confused: The crack was about 180* around - my guess it waould have gone out totally on the next trip or at least the end of the season:eek:

Originally posted by mj
how did you crack a bellhousing?

I've got a cracked aluminum bellhousing on an SM465 too. Bought a 350 SBC coupled to a 465, and when I unbolted the trans, I saw the crack (actually I saw the crack before I even started working on it, but it looked like just a line in the grease or a casting mark, and I didn't pick up on what it was). I'll be switching to cast iron.

the 420 is only 10.5'' long

I guess you havent priced 420 trans case adapters
a lot of $$$ to go from a 6.56 to 7, could get a doubler for that coin
465s are dime a dozen

Hammerdown, If your rear shaft is too short what about the front? It has to be bad too. I have a similar set up for my Toy. I had a TH-350 and put an SM-465 in its place. The only difference is I am running a divorced 205 to help driveshaft angle. By the way, I love the SM-465. Check out my site, there is a picture of the divorced T-case in my truck.
www.geocities.com/mudtruck44

What years had the cast iron bellhousing?
I have an aluminum one for when I swap in the 463 but now I think I will scrap that idea.
I have a cast iron one in it now but it is from a 1956 truck and the starter bolts to the front of the housing adn not the bottom.
Not only that but the headers have to be custom to clear.
Which is why the current header has not been changed.
It has been on since 1980 and is rotted out beyond belief.

I have one of the old steel bellhousings and I had to get a starter that bolted to the bellhousing. Unfortunately, I have no idea what year it is.:rolleyes:

My starter bolts to the front of the housing.
On the newer stuff it bolts to the bottom of the block.