[66 chevy truck]

Hey guys. I have a chance to buy a 1976 K-5 Chevy blazer (automatic) . I what to put a 4-speed manual transmission in it. i was wondering what transmissions fit in it and what type of modifications i will i have to do.


Thanks in Advance

[poncho62]

Whatever manual tranny you put in, it has to come grom a 4x4, so it will bolt to the transfer case. Also, the standard tranny models had manual locking front hubs.......your automatic does not...unless they were added later.

[66 chevy truck]

Thanks. so would a 4-speed from a 1972 chevy 4x4 fit without to much trouble

[poncho62]

Should be a bolt in...............dont forget about the pedals and clutch linkage etc..............That stuff may be different since the body styles changed in 73.

[66 chevy truck]

will i have to change the transfer case?

[poncho62]

Don't think so, but if you can get the one from the 72, I would.

[66 chevy truck]

thanks poncho hopefully everything bolts up right

[66 chevy truck]

Is it true that the older Chevy blazers were all time 4-wheel drive.

[poncho62]

Yes...the ones with an automatic trans. At least my 73 and 75 were.......

[66 chevy truck]

Thanks for the replies. Ill see if i can get it to fit

[75gmck25]

The transfer case input shaft connection has different spline counts for manual, TH350 and TH400. If you want to use a manual trans, the best T-case would be an NP-205, since most of them were mated to manual transmissions. Most automatics had the full-time NP-203 in the 70's, and then later the lighter duty NP-208.

Are you just trying to just change the transmission, or do you want build a heavy duty rock crawler. Many off-roaders combine an NP-205 with the range box of the NP-203, and get an ultra low geared combination. But you can still run it at 1:1 on the highway by putting both transfer cases in high.

This is an article on that combination.
http://www.bc4x4.com/tech/2000/gordt...gordtcases.cfm

Bruce

[Bryan59EC]

Originally Posted by poncho62

Yes...the ones with an automatic trans. At least my 73 and 75 were.......

Many people had changed their full time to "locking" hubs on thes trucks for gas mileage.
For years growing up in Idaho I drove nothing but manual hubbed 4x4 trucks.
These trucks usually had posi in the front (at least where I was)

When I moved to Utah, I bought a 78 Chev full time 4x4 that had this locking hub conversion on it. In order for the truck to move, the transfer case had to be in 4-loc. If it was just in 4-hi with the hubs unlocked, it would not move at all. I don't know, but it seemed to me the tranfer case had a differential of it's own.

I put the full time hubs back in and just fell in love with that pick-up. No longer did I have to get out to lock and unlock hubs, rain, snow or ice was never an issue. Gas mileage did NOT go down.

Of course that truck only got 9 mpg---uphill, downhill, loaded, empty, tailgate down, engine off.

Bryan

[poncho62]

I never did understand the reasoning for the locking hubs with an automatic. Like you said, you had to run in 4lock.....so you were turning all those gears and chains anyways, except for the link in the axle.......................No way it would get better mileage. I used to get 12-14 with mine. Lighter foot maybe.....

I built this Ford truck on a Blazer frame..........Full time 4x4.........great plow truck.

[Arrowhead]

I put one of those full time to part time conversions in my 73 blazer back in the day. It had a locking gear you put in the transfer case and you swapped in the lockout hubs. Don't know if it helped my gas milage, but it sure was a lot more fun doing donuts!

[75gmck25]

My '75 GMC has the original NP-203 full-time 4WD transfer case, which has a differential built in to the T-case. I usually run in High, which allows the front and rear wheels to turn at different speeds (all wheel drive). If I run in High-Lock, the T-case differential locks front and rear together and I get traditional four wheel drive. I also have a low and low-lock position.

The front hubs are fixed with a stock NP-203, and cannot be unlocked. If I unlocked the front hubs in high it would be like lifting one tire of a nonlocking differential, and I wouldn't be able to get the truck to move. I'd have to go to high-lock to move the truck.

There are a couple of part-time 4WD/2WD conversion kits (e.g., Milemarker) for the NP-203, either a light-duty or heavy-duty version. Both have problems with lubrication in the T-case in the 2WD position, since they don't drive the oil pump in 2WD. You have to put them in 4WD periodically (every 200 miles or so) to keep the T-case lubricated.

My truck also has the G80 option, which is the GM Gov-Lock rearend. Front locking differential was not an option, and won't work well for driving on pavement. If you want to lock the front diff, you need an air locker or some other selectable locker that you only use off-road or in snow.

Bruce