3-speed to 4-speed conversion

[aksidentproan]

I got a line on one and was wondering what would be involved. Could I just move my current crossmember or do I have to find a new one? Is the 4 speed(SM465) so much longer that I would need new driveshafts? If I get it it comes with an NP205 and adapter. Thanks.

Evan

 

[69K5]

im doing the same thing. i did a thread yetsreday here and in the garage. no one said anything about moving the crossmember. if you add a lift the length will help. the biggest prob everyone seems to refer to is the pedal rod to the master placement.

nathan

 

[Blazer1970]

I went from a 3 speed with a Dana 20 to a 465/205, and I had to use the crossmember from the truck that had the 465/205. That crossmember has about an inch more drop in it, and the 205 would hit the floor pan with the one that came in my Blazer with the 3 speed/D20.

 

[aksidentproan]

Ok. I drove to BWI Airport yesterday and picked up my 465/205 combo that I got from batmanjr. I am still unclear on the crossmember situation. The 4-speed with the 205 is a few inches longer then my 3-speed with a 205 so do I have to relocate the crossmember or just modify the area where it mounts so its 1" lower? If I have to get a crossmember from a 4-speed truck where could I find one? First generation blazers a few and far between in Maryland. Thanks.

Evan

 

[70~K5]

The crossmember is the same on all NP205 first gens. You can use one from a TH350/NP205 with your SM465/NP205. You also need the side mount for the TC to the frame.

 

[Blazer1970]

You do not have to move the crossmember back. It mounts in the same frame holes. If you had a Dana 20 to start with, you will either need to find a 205 crossmember, or space your old one down about an inch. I am not sure of the exact amount of difference in drop. I did try to install the 205 with the Dana 20 crossmember though, and it did hit the floor pan, so I know you have to drop it some. The bracket that mounts the side of the t-case to the right frame rail also uses the same holes for the D20 or the 205.

 

[aksidentproan]

Can I use the mechanical clutch(not hydro) setup from my 3-speed on the SM465? Thanks.

Evan

 

[70~K5]

Poster: aksidentproan
Subject: Re: 3-speed to 4-speed conversion

Can I use the mechanical clutch(not hydro) setup from my 3-speed on the SM465? Thanks.

Evan

Comeon people, Do you really think Chevy would have a different clutch linkage for the 3 spds from the 465??? /forums/images/graemlins/confused.gif /forums/images/graemlins/deal.gif /forums/images/graemlins/eek.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif

 

[Blazer1970]

Clutch linkage is exactly the same.