72 4x4 overdrive options

[WestButteTruck]

What is a good combo with the least amount of modifications for adding an overdrive transmission? Right now I have the TH350 with the NP205. I would assume the most common route is the 700R4 but with what transfer case?

[YoungPup1977]

The 700r4 has the same bolt pattern as the T350 has for bolting up to a NP205, but the output shaft on the stock 700r4 is to long. Advance adapters sells a output shaft for the 700R4 to fit the np205 transfer case. I suggest to leave the np205 in its stock location and move the engine forward since the 700r4 is longer than the t350. this will allow the transfer case shifter to remain in its stock location (no cutting on floor) and no cutting and balancing of the front and rear driveshafts....

With the 700r4 you can reuse the bracket for the TV cable that was once used for the T350 detent cable and the shift linkage can be reused as well with some small changes. The cooler lines can be reused and no reforming of the cooler lines are required. Also, the flexplate from the T350 can be reused for the 700R4.

Some use the 4L80E, which they can chime in and supply all the requirements on that conversion......but if you are looking at the cost of the conversion I would think the 700r4 is a bit cheaper but I have never really made the comparison...

Use a stock 700R4 pan which has enough clearance of the CV U-Joint on the front driveshaft.

Ensure the 700R4 that you get has a type 1 VB which has the provisioning for the TCC shift valve, this eliminates any electrical connections to the 700R4...all shifts 1-2, 2-3, 3-4, and TCC lockup would take place by shift valves in the Valve body....no need for external-internal switches/vaccum switches/pressure switches, that famous switch wired to the TCC solenoid (on the dash) for TCC lockup that most people forget to switch off and on during driving....

PM me if you are interested in a 700R4 built for this application, I have several in stock ready to go....

cost of the AD 700r4 output shaft I believe is around 175 bucks but you can get one from Transmission technologies for 59 bucks....

[WestButteTruck]

Thanks for your input, I appreciate it. I like the idea of moving the engine forward some, it's pretty tight back there already. With this build, I'm not looking for a lot of modifications so this seems pretty good.

[YoungPup1977]

Here is a pic of a 700R4 bolted up to NP 205 in a 1972 blazer frame, and yes it gives you extra clearance when moving the engine forward on a blazer or truck 4x4....if you have to pull the dizzy out it makes it a bit easier.....

Transfer case is in the stock location as you can see the cross member bolts uses the same locations and the right side mount to the Transfer case stays in the same location as well....

this shows a empty 700r4 for mock up purposes....

[WestButteTruck]

Nice.

[b454rat]

There is also a spacer that bolts between the tranny and spacer, so don't need the output shaft swap. Nice if don't want to tear into the tranny. Offroaddesign.com has em for $100 I think. Prolly shop around and find one cheaper.

[YoungPup1977]

Originally Posted by b454rat

There is also a spacer that bolts between the tranny and spacer, so don't need the output shaft swap. Nice if don't want to tear into the tranny. Offroaddesign.com has em for $100 I think. Prolly shop around and find one cheaper.

When using this spacer, you must consider the engine is moving 3 more inches or you are now moving the transfer case away from its stock location which may create cutting/balancing driveshafts and the stock shift linkage has to be modified differently than just using the AD output shaft... I know no one wants to open the trans up or have a trans shop do the work, $$$$....

[Bigdav160]

I moved my engine forward. My stock fan shroud doesn't fit anymore, I had to modify the coolant hoses, had to massage the A/C lines, had to move the shift linkage brackets and lengthen the exhaust pipes.

But better than building new driveshafts, moving the crossmember and cutting new holes in the floor.

[YoungPup1977]

Here is the pic of the stock shift linkage, when using the aftermarket output shaft it makes a bit easier to install the stock linkage.... the bracket on the frame all you do is use the top bolt which bolts the bracket to the frame and move the bottom bolt forward, which a bolt/hole already exists for the cab mount brace on the frame....

Just another note, if the spacer is used as mentioned above than this linkage is not that easy to modify because of the additional 3 inches of the spacer which either moves the transfer case (cutting driveshafts required) or the engine forward which the 700R4 is already longer than the turbo 350 so you are adding the length of the spacer to this.....

Hope this makes sense, and Thanks for listening.....

[YoungPup1977]

I checked for the 4L80E conversion kit for the NP 205 @ Advance adapters and it only sells for 847 bucks.... sort a tosses a turd in the punch bowl right off the bat.....