I need help with what overdrive to install.

[69GWC]

How does it work on a 4wd.? does it go inbetween the tranny and TC then.?

And then it just has a another gear inbetween all the other gears so it does not have a very big span between gears then and then the last gear is your over drive.
seems like it would make shifting pretty seemless or smoother.

[72MARIO]

they work only in 2 wd. Unless you have a divorce transfer case Then you can have 4wd with the gear splitting.

[haysonj]

Originally Posted by 72MARIO

they work only in 2 wd. Unless you have a divorce transfer case Then you can have 4wd with the gear splitting.

There is a lock out function that locks out the GV when you shift into 4 wheel drive

[SS Tim]

Originally Posted by 69GWC

How does it work on a 4wd.? does it go inbetween the tranny and TC then.?

And then it just has a another gear in between all the other gears so it does not have a very big span between gears then and then the last gear is your over drive.
seems like it would make shifting pretty seemless or smoother.

Most units mount to the transfer case at the rear driveshaft output and are used in 2wd modes only. But it can also be installed ahead of the transfer case in some applications. Here is a 70 K20 NP205 installation.
Eventually my plans are running a TH475/GV in front of a divorced203/205 t-case.

In use, it overdrives each gear so there is about half the rpm drop between gears as it works up automatically from a stop. Starts out in first gear (1st), hits O/D shift point then O/Ds first gear (2nd) until trans. upshifts to second (3rd). At the same time the O/D reverts to direct drive. Progressing up in second gear (3rd) until it hits the O/D shift point again it O/Ds second gear (4th) until the trans shifts into third (5th). At the same time the O/D reverts to direct drive. Then it progresses up in third gear (5th) until it hits the O/D shift point again, then it O/Ds third gear (6th). This is all very smooth.

[b.eddy's72]

Jocko that chart is awsome but I have different actual outcome than the chart with my truck.

Mine is a 67 C20 with a 400 and 4.10's but my tach is sitting around 2900 rpms at 55 mph. That mph is actually going off of GPS since the speedo isnt accurate. That now has me wondering what my issue is.

I am actually considering converting to a 700r4 (have 1 sitting) and changing to a 14 bolt rear with 3.73's to make it more highway friendly. I live 6 miles outside of town and have only driven it in once because it sounds like the motor is gonna shoot pistons at 65 mph.

[shawno72]

I just did a 4 speed granny box manual to an auto 700r4. I will never look back. Check the last few pages of my build thread for the details.
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[JointTech]

Originally Posted by SS Tim

Starts out in first gear (1st), hits O/D shift point then O/Ds first gear (2nd) until trans. upshifts to second (3rd). At the same time the O/D reverts to direct drive. Progressing up in second gear (3rd) until it hits the O/D shift point again it O/Ds second gear (4th) until the trans shifts into third (5th). At the same time the O/D reverts to direct drive. Then it progresses up in third gear (5th) until it hits the O/D shift point again, then it O/Ds third gear (6th). This is all very smooth.

this is awesome. So is that settable?
haysonj in a previous post in this thread said his goes 1-1od-2od-3od when in auotmatic mode.
seems like he is skipping the "normal" 2 and 3 gears and going direct to OD on those. So is that factory set or a laptop hookup or a knob or what?

[haysonj]

Originally Posted by JointTech

this is awesome. So is that settable?
haysonj in a previous post in this thread said his goes 1-1od-2od-3od when in auotmatic mode.
seems like he is skipping the "normal" 2 and 3 gears and going direct to OD on those. So is that factory set or a laptop hookup or a knob or what?

There is a red/green light on the control, when the green light comes on it shifts. This box is controlled off the speedo cable and I don't think it is adjustable unless GV could do it for you. Mine justs shifts at the points that work best with the rear gears I have.