4x4 conversion questions from a newbie

[82smokindiesel]

This is my first time posting here, but a long time reader of this site. I have a 1982 Chevy K20 6.2/400/208. I wanna put a sm465 instead of the 400 because its going south on me. I was "told" that the 465 will go right in where i needed it to go, as long as i have the adaptor to go between the tranny and transfer since its already a 400 turbo. i already have a 465 but its from a 2wd, will that still work with it? i was told that i would, or will i have to get the 4x4 tranny, from what ive saw the only diffrence is the end of the shaft, the 2wd had threads for the nut and the 4x4 doesnt, but mabey someone can explain this to me. Second, i have a buddie that has the adaptor, but i cant look at it for another couple of weeks because im awfully busy here. Is there a coupling sleeve that goes between there or is the shaft long enough? Thanks for helping me out here, I love my truck and just wanna make it more enjoyable to drive. You guys are great here.

 

[big83chevy4x4]

you will almost need a 4wd 465 out of a 81 and newer truck, the 2wd output shaft is not long enough. not even close. if you get a output for a 465, you will need to teat the tranny apart to replace it.

there is no coupler for the 208.

 

[tRustyK5]

It'll be a good bit of work to do the swap. You'll need the brake/clutch pedal hanger with pedals and linkages and stuff. You'll also need to decide if you are gonna put up with mechanical clutch linkage or pony up for the hydraulic clutch stuff right away.

I recomend the hydro clutch, it's a ton easier on the left leg. If you can't do the hydraulic clutch at the very least make sure you use a diaphram clutch. If you use the Borg & Beck three finger style with mechanical linkage you'll hate it. I know I did.

With hydro, you'll also need a bellhousing from an '85-91 SM465. It has all the junk for the slave cylinder on it. You'll also need the clutch master which bolts to the firewall. Most, if not all, the parts for hydro are still available and IIRC MJ here has a complete parts list. There is also a write-up on the home page.

You will need a flywheel for the 6.2 specifically. A pilot bearing or bushing, pressure plate, clutch disc etc etc.

81 and up SM 465's were backed by the NP208 and were 32 spline input with no coupler. 2WD SM465's were 35 spline output so using one is out of the question unless you want to swap mainshafts...

Another option is to find and buy a complete 465/205 combo and swap that in. Kill two birds with one stone so to speak. Unfortunately you'll likely need driveshaft shortening/lengthening no matter which combo you go with. The 465/208 might work out the same length as the 400/208...I've heard GM tried to keep all the combo's the same overall length when they intro'd the 208 in 81.

In my opinion the 6.2 backed by the SM465 is a great combo. I run the same tranny behind my 6.2 and aside from the lack of overdrive I love it.

Good luck.

Rene

 

[dyeager535]

I've got a few (including clutch) parts manual pages up.

parts

 

[tRustyK5]

Cool deal Dorian, prolly come in handy for myself sometime too.

Rene

 

[82smokindiesel]

Thanks for explaining the transmission to me. Well looks like im goin to be looking for a 81+ 4x4 tranny. one question about those now, is it the same transmission thats bolted to the np205's also? i think i read that the spline count changed in somewhere around 85 but im not sure there, someone can explain that one. I have everything i need other than the transmission and i have to pick up the adaptor sometime when i go to my buddies place. I have the mechanical setup. Hey you guys are a great help. Thanks for everything

 

[tRustyK5]

From 73 to 80 the 465's were 10 spline when coupled to either the 205 or 203 T-case. 81 was the first year for the 32 spline output. It's pretty rare but GM did build some one ton's with hydro clutch, 32 spline 465 and a 205...those would be 85 to 91 I think.

Rene

 

[mudjunkie 82]

is there an issue with the rear drive shaft since the 465 is shorter than a t400???????

 

[trukman1]

Yup! The driveshaft lengths are different. This may be far fetched but I once did this and what I did was run an ad in a local trader magazine asking to do a side-by-side swap...sure enough, a fellow with a clean 4spd truck wanted to swap to an auto tranny so we did a side by side swap so I got the steering column, pedals,tranny/transfer case, driveshaft, everything. Believe it or not, lots of people are beginning to want the automatics. IMHO, I'd be more inclined to replace the auto with another 400 and go on. BTW, the adapter is VERY different. Let me know if you want to sell the adapter if you go the 4spd route!! Good Luck!