Tranny/transfer case question on the 3 speed Blazer

[72freak]

While the 1968 dually project is off to paint and body, I am going to start on the 1972 Blazer. Im sure this is covered in here somewhere but I am going to ask it anyway.

Its currently a 3 speed that "Billy Bob" converted to a floor shifter. I want to convert it to an automatic.

I know i will need a different bell housing but can I use the same transfer case????

What do I do?

I have also given thought to going with a 4 or 5 speed......what can I use?

[Blazer1970]

Chances are that you have a Dana 20 t-case now with the three speed. That case will not work with an automatic. Your best bet would be to find a TH350/NP205 combo with the adapter. Actually better yet and often cheaper would be to find an entire '70 - '72 truck with the tranny that you want and start swapping parts. That way you have the steering column, crossmember and a hundred other parts that you will need for the swap.

[Classic Bowties]

Originally Posted by Blazer1970

Chances are that you have a Dana 20 t-case now with the three speed. That case will not work with an automatic. Your best bet would be to find a TH350/NP205 combo with the adapter. Actually better yet and often cheaper would be to find an entire '70 - '72 truck with the tranny that you want and start swapping parts. That way you have the steering column, crossmember and a hundred other parts that you will need for the swap.

x 2 the blazer will have a Dana 20 transfer case if original, unless somthing has been swapped in at some point. There is no way to use the dana t-case with any automatic tranny. You need to find a complete TH350/NP205 with the adapter, as Blazer1970 stated above it would be best to find a donor rig with the combo you want, that way you get all needed parts in one shot. Another thing to remember is that you will need the 205 x-member setting under the adapter on the 205 combo, or you will need to figure out a way to space your Dana20 x-member down about an inch or so, otherwise the 205 combo will hit the floor pan. The 205 shifter also comes through the trans hump cover in a different spot than the Dana 20, so remember to try and get the auto/205 hump cover from the donor truck or you can always cut a new hole and weld a patch to your original hump cover. Cb

As a side note: I just converted a very clean & original one owner 71 K/5 with 87K original miles from the Saginaw/Dana20 combo to a Th400/Np205 so I have all the just removed oe manual parts (stored inside heated shop) available if anyone is interested in putting their K/5 back to original with this type setup. I have the trans & transfer still bolted together including case shifter and mounting parts, the bellhousing, flywheel/pressure plate/release fork, the manual pedal set, clutch linkage, a super nice & tight 3 on the tree column, both shift links and both front & rear blazer drivelines, to be sold as a complete package only. All parts in great working condition and were only removed for the reason of owner getting tired of shifting a manual, I can take some pics if anyone is interested. Lmk...

[meathead95]

i have a 72 swb 3spd with an np205 combo i bought from the origional owner so they where available

[Blazer1970]

Originally Posted by meathead95

i have a 72 swb 3spd with an np205 combo i bought from the origional owner so they where available

In a pickup truck, yes. A Blazer came with a Dana 20 behind the three speed.

[meathead95]

gm used many applications. how do you know for sure a np205 didnt come in the blazer behind a 3spd?

[special-K]

I`m pretty sure the Blazers used the Dana20,where the Suburbans and pickups used NP205s.

[fun in dirt]

I see that Classic Bowties said "The 205 shifter also comes through the trans hump cover in a different spot than the Dana 20..."
So that got me to thinking... I have always thought my Blazer had a 205. However, I've noticed that my transfer shifter is on the driver's side of the the manual stick. While alot of other trucks I see, have it coming out on the pass side of the hump. (My blazer originally had a 3 on the tree, but a PO converted it to 4 in the floor - granny low +3)

[Blazer1970]

Originally Posted by fun in dirt

I see that Classic Bowties said "The 205 shifter also comes through the trans hump cover in a different spot than the Dana 20..."
So that got me to thinking... I have always thought my Blazer had a 205. However, I've noticed that my transfer shifter is on the driver's side of the the manual stick. While alot of other trucks I see, have it coming out on the pass side of the hump. (My blazer originally had a 3 on the tree, but a PO converted it to 4 in the floor - granny low +3)

The early 205s ('69 and '70?) had a shifter handle that had a 90 degree bend over the adapter so that it came out on the driver's side of the tranny shifter. The later ones had a straight shifter that comes up to the passenger side of the tranny shifter.