TH350 to 700R4

[OldCreek]

The 700r4 output shaft is not fully splined....and cutting it down does not leave enough spline length to fully engage the np205. I don't know how some others have done it, unless they dremeled out the shaft ....but from what I can see you need the adapter or a new output shaft.

[big dump]

Bobby, did you install the A/A shaft yourself? How difficult was that process?

[OldCreek]

Ok, here's some more info...

Spacer made by Teckpak USA. website: www.teckpak.com or www.techpak-fitzall.com

Techpak part# 7Q-35A


This spacer is made by Teckpak. The package I got came with o-rings, bolts and some other small parts. Places like AA and Red's are reselling them. There are other places online...google Teckpak's part # and you will find an online seller...I just did. The place I just found wanted $75. Good luck with your search.

If your tranny needs rebuilt, then replace the shaft. If not and you want to save some money use the spacer. Is the spacer set up as strong...I dont know.

[big dump]

Thanks for the info OldCreek.. I found an online dealer that sells for $75, plus about $25 to ship. I find it hard to believe they're getting that much for a cast piece of aluminum, but it's still half the price of the A/A route, and don't have to crack open the transmission. I'll keep you posted on which route I go..

[71RestoRod]

I also used the AA output shaft with the 700R4/205 and moved the engine forward. So far it's working great for me.

One advantage to the spacer that I haven't seen mentioned here is that the spacer will give you better clearance between the 205 front yolk / CV and the pan under the 700R4. With the AA shaft you're pretty much stuck with a stock pressed steel pan but I've heard that using the spacer provides enough clearance for a deep pan w/o modifications. Had it been available at the time (or had I known) I would have gone that route instead and moved both the engine forward and the cross member back.

[1971short4X4]

i did this swap the way pumpkin and others did 5 years ago on my 1971 swb pickup with np205. got the revised output shaft from bowtie and then moved the engine forward 2 inches. used a lokar linkage for the tilt colum to tranney. Installation works and looks factory. that is the way to do it as far as im concerned.

[BobbyK]

Originally Posted by big dump

Bobby, did you install the A/A shaft yourself? How difficult was that process?

Nope, got the conversion shaft from A/A then when I got around to getting my 700R4 I talked to the guys at TCI and they said send us the shaft and we'll build you a 700 with it in it.

I don't think TCI were offering a production converted 700R4 at that time.

[Wildstreak]

@ bobby
what did you do about your gear indicator? did you replace or?

[BobbyK]

Originally Posted by Wildstreak

@ bobby
what did you do about your gear indicator? did you replace or?

Just reused the factory indicator.

Just fiddled with the factory linkage to get things to line up. For the most part they do. 1st gear is off but how often do I have to manually shift into 1st.

[Wildstreak]

thanks man!

[big dump]

Placed the order today for the 7Q-35A spacer from transmissionpartsusa.com. With shipping the cost was $100.00. Start the conversion with pics once I receive it. Anyone find a replacement indicator that does have D,1,2,3? I'm going to start looking, but like bobby said, it's not the end of the world if I can't find one, not shifting into 1st manually that often anyway.

[RAB38]

dont mean to highjack but has anyone done a 4l80e with either a 205 or 241?

[big dump]

Quick update-

Got the TH350 out, rebuilt the NP205 with new seals and gaskets, rebuilt the factory cast adapter with new seals, got that all bolted up to the 700R4 with 10mm studs that I cut down to fit. Also got a kick down cable from the local junk yard. Ready to bolt the tranny up in there, and see what I have to do to re-locate the crossmembers etc. to get the transfer case up there and bolted in.

Pics to come soon..

[Dusty71blazer]

I haven't seen any other t-cases mentioned in this thread. What are the other options? Do any other cases fit without having to move the engine forward? For example there is a rusty '83 Chevy 4x4 p/u with a rebuilt 700R4 & Rebuilt 208 T-Case for sale locally. any experience swapping in a 208 t-case? If anyone has info on this or any other swaps please share. Also if anyone has info on the over all length of the different combinations that would be great to have too. I plan to do this swap when I find the right parts (at the right price) Thanks!

[SeventyOne]

Did anyone running a 700r4 have to deal with lockup converters and switches/wiring like these?

http://www.jegs.com/c/Transmission_L...10733/10002/-1

I have a 700r4 K case out of 91 chevy and it has that little electrical plug on the side that I was told is for the above mentioned lockup switch....just wondering what anyone else has done.

[Wildstreak]

I havent wired mine up yet, but I bought the tci lockup kit and it cam with the pug in that youre referring to.

[Wildstreak]

this is the one I bought

http://www.summitracing.com/parts/TC...0/?image=large

[big dump]

Dusty, the reason you haven't seen any other cases mentioned here, is because this thread is about a 700R4 with a NP205. I'm not sure about a 208, the dims are probably different, and either way you'll have to make driveshaft modifications and others to accomodate.

Guys, is the Lock-Up kit necessary for the 700R4? I was under the impression that you didn't need to run it. Is it just for manual lock up? from the guys using them or planning to use them, what's the benefit?

[Dusty71blazer]

Originally Posted by big dump

Guys, is the Lock-Up kit necessary for the 700R4? I was under the impression that you didn't need to run it. Is it just for manual lock up? from the guys using them or planning to use them, what's the benefit?

Yes, it is necessary, you'll burn up the trans if you don't lock up the TC- either manual or automatic. Benefits are there too- gas mileage, etc. There is quite a bit of info on the web about this. The other thing that is very important is making sure you have the proper TV linkage and that is is adjusted properly. From what I have learned, if you get these 2 things right you'll love the swap, don't and you are in for some headaches.

Sorry, I didn't realize this thread was specific to the 205 t-case- the title only specifies the trans swap.

[big dump]

Yeah, I've heard that about the TV cable, I think it was mentioned by another member earlier in the thread, but I was not aware of the TCC Lockup being needed. It makes sense that you'd want it to lock-up on the highway, when you're not shifing through the gears to keep it cool, and reduce the RPMs. Anyone have experience with the Bowtie Overdrives kit below:

http://www.bowtieoverdrives.com/cata...php?ITEMID=332

[SeventyOne]

Looks similar to the one posted above by Wildstreak...$20 more expensive, however.

[packers05]

You do not need the lockup, I made my grand national lock when it hit second gear on up through the gears , it was awesome felt like a speed shift of a 4spd!! I ran kennebell cam ported heads big turbo and monster injectors it required a art carr torque convertor but man did people say wow when the first couple shifts hit!!! sorry i got off track but point is do what you want just know a convertor in non lockup creates a lot more heat than a locked one and that heat is wasted energy!!

[Wildstreak]

from what I was told from every mechanic I talked to, the two main failure issues with the 700r4 are cause by the T.V cable and the lock up not working properly or not being hooked up properly. But thats just what Ive heard. I dont have much personal experience with them tho.

[Dusty71blazer]

Originally Posted by Wildstreak

from what I was told from every mechanic I talked to, the two main failure issues with the 700r4 are cause by the T.V cable and the lock up not working properly or not being hooked up properly. But thats just what Ive heard. I dont have much personal experience with them tho.

x2

From what I understand it will work without lockup, but not for long...

[big dump]

Good points. After some research, looks like the difference in the two kits (TCI vs. Bowtie Overdrives) is that the Bowtie kit includes a new brake switch, as well as the internal wiring kit for the 700R4. I think I'm going to order the TCI kit, hopefully that will be sufficient.