TH350 to 700R4
 

I know this topic has been beat up in the past, however, I have yet to find a good step by step for someone trying to do the swap, so what I'm hoping to do is to get some tips, and feedback from you guys, and do a how-to write up for the FAQ section when I complete mine.

I have already picked up a 4x4 700R4 out of an early 90's Blazer, and am about ready get going on the swap. I'll be swapping into my '72 4x4 K5 with the NP205. Any and all help is appreciated, or if I've just totally missed a comprehensive write up, please forgive me and point me in the right direction. :help:

Re: TH350 to 700R4
 

interested also

Re: TH350 to 700R4
 

I know there is some information on the CK5 forum, and I've found some information on the linkage etc. on the site below, but I'm really hoping for a more in depth explanation of the fabrication or fitments of the transmission itself to the transfer case, as well as the drive shaft mods, etc. that have to be done if any. I know there has to be a bunch of guys that have done this swap..

Also, most of the information on the TV linkage that I've found shows the swap with a carbureted vehicle, is it the same for TBI? I've got a factory style TBI setup that I swapped into mine.

Link:

http://purplesagetradingpost.com/sum...o/700R4p1.html

Re: TH350 to 700R4
 

pm sent !

Re: TH350 to 700R4
 

Weather it's carb'd or injected doesn't matter, it's a tranny adjustment, nothing to do with fuel management.

Re: TH350 to 700R4
 

Thanks VT. I was more talking about the linkage and adjustment for the TV, but yeah, that makes sense. I guess it really is just a matter of making it work with whatever throttle linkage you have carb or TBI

Re: TH350 to 700R4
 

VT, have you done the swap on any of your rigs? I'd be interested how many guys are using the new output shaft method from AA rather than the spacer kit that I've seen.

Re: TH350 to 700R4
 

Not many guys are running 205s behind 700r4s due to the cost of the conversion parts. A 700r4/NP241 is a much cleaner and easier swap. It also gives you a better crawl ratio due to the lower gears in both.

As far as the TV cable goes, depends on what you're running. If you're carbed, there are a number of brackets available that bolt to the carb to ensure that the TV cable travels the correct distance. For TBI, EFI, etc, your best bet would be to find a truck that has a 700r4 with TBI from the factory and pull off the TV cable bracket to reuse on yours.

Re: TH350 to 700R4
 

Not in any of these trucks but I've had trucks with 700r's in em before.

Doing a 700r/241 with TPI in my current build though.



AJ also gave a better description than what I offered above, basically if you find the right bracket for your application and you'll be all set. ;)

Re: TH350 to 700R4
 

Hmm, I'd rather stick with the 205 that I have, however, I guess if I'm going to end up buying a spacer or conversion that costs the same as a 241, it's kind of a wash..

Re: TH350 to 700R4
 

In order to put a 205 behind a 700r4 you need to have a special output shaft installed into the trans. I ordered my 700r4 from Bowtie overdrive with the shaft installed. Rather than modifying the drive shafts, I moved the engine ahead 2 inches by just relocating the engine crossmember and redrilling holes to bolt it up. This way if for some reason I want to go back to the th 350 its just a matter of shorteing the exhaust and bolt it back togeather.

Re: TH350 to 700R4
 

Has anyone had success with the 7Q35A spacer kit that you can buy online? It seems much easier to me in theory to go that route than to swap output shafts on the transmission. Also, aren't the NP241 cases aluminum? I'd probably rather stick with a steel case 205 if possible, despite the low range, it's more of a driver than a wheeler for me and I'm trying to do this as affordable as I can so I'd like to avoid buying a new TC.

Re: TH350 to 700R4
 

Yes, the 241 case is aluminum. Really, the 241 has only two weaknesses which are fairly easily remedied. First, being the aluminum case which you can take care of with a good skid plate. Second being the slip yoke on the rear output. A JB Conversions SYE (slip yoke eliminator) takes care of that, and it shortens the overall length of the 241 by roughly 4".

I don't really see the driver/wheeler argument being valid. Both cases have strengths in each area. If you told me you were gonna wheel the snot out of your rig and had plans for a doubler in the future, then absolutely go with the 205. If you're gonna put 700+hp to the ground, then yes, the 205's gear setup would holdup better than the 241s chain. If you want to be able to say, "I've got a 205", then keep the 205. If none of those are true, I still have to lean the direction of the 241 because it mates up cleaner to the 700, it has a deeper low gear, it's lighter (by about 50lbs), with a $60 clocking ring you can clock the 241 up to give you more ground clearance than a 205, and you can pick one up fairly cheap.

Re: TH350 to 700R4
 

Gotta agree with AJ, nice dissertation dude. :chevy:

Re: TH350 to 700R4
 

Yeah, those are all good points, and I don't disagree, however, I already have a good solid transfer case, and I would like to do it on the cheap if possible. I can see both sides of the fence, I'm just trying to gather information before I decide on which direction to go, that way I can make an informed decision and not run into many surprises..

Re: TH350 to 700R4
 

Eitherway you decide to install the 700r, going to a 4spd auto will make your blazer sooo much more enjoyable to drive, especially on the interstate.

Having a better 1st gear with a 30% overdrive to boot, will be sweet.

Re: TH350 to 700R4
 

Yeah, I agree, especially since it's my daily driver now. Got rid of the Jeep this week in favor of getting a boat..

Re: TH350 to 700R4
 

Here you go:

This is a 4l60E not 700R4 though. The rear of the 4l60e is converted with an adapter from AA. It adds a reluctor ring and sensor, also. It basically makes (this model of the 4l60e) the 4l60E look like the 700R4. Then, I added the spacer you listed above...also bought from AA (although they don't list it online, etc.) I still had to cut a little off the output shaft so it fits flush in the t.c. adapter....you can easily measure that. (roughly 3/8, if i remember correctly).

From left to right:

NP205, t.c. adapter, spacer, 4l60e conversion adapter with reluctor ring

Re: TH350 to 700R4
 

Good picture OldCreek. I called up Red's Transmission Parts that was mentioned in a previous thread, they now want $95.00 for the 7Q35A spacer. I'm going to dig around a little more before I spend that, but that's the way I'm thinking about setting it up.

Re: TH350 to 700R4
 

yeah, I think I got that 700r4 adapter from Red's for like $50bucks a couple years ago....but, seriously, AA sells the same adapter from the same manufacturer. I don't think they raised their prices to $90. Call AA first!

Re: TH350 to 700R4
 

I called them yesterday, and the lady didn't know what I was talking about. Going to try again today, try and talk with a tech or whoever..

Re: TH350 to 700R4
 

They still don't really know what I'm talking about. The only kit that they sell or at least the only one they know about is the new output shaft conversion, which is $172.50...

Re: TH350 to 700R4
 

I didn't do the work but you can do it without the adapter. The shafts are the same spline, the 700 is just too long. My tranny guy trims the end of the shaft and makes sure the OD is correct to engage correctly into the 205. Works great for me, I did the engine move forward deal, left transfer case in place.

Re: TH350 to 700R4
 

Well, bottom line I guess is that I just need to pull the TH350 out of there, shoe horn the 700R4 in there, and see what the best course of action is. I usually like to research, and make sure I have what I need before I start a project like that, but this one has so many different ways of doing it, I'm just going to have to jump in. I'll keep you posted..

Re: TH350 to 700R4
 

TCI built 700R4 with A/A output shaft bolted directly to orig. NP205. The A/A shaft converts it to the requiered 27spline needed to mate with the NP205. Of course it also makes it the right length to mate to the NP205.
NO SPACER NEEDED.

http://images103.fotki.com/v422/phot...pg_orig-vi.jpg

Here it is on their site.
https://secure.advanceadapters.com/i...ds/50-6900.jpg

http://advanceadapters.com/product/1775/50-6900.html



Moved the eng forward approx. 1"7/8", redrilled crossmember holes in frame.

Removed bottom bolt of auto trans linkage bracket and swung the bracket forward.

http://images26.fotki.com/v888/photo...pg_orig-vi.jpg


That was that.
Kept my driveline angle and lengths at factory spec. No changes there.

Just had to fiddle with the shift linkage to get the shift indicator to line up.

I did this swap in 1999.




.

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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..

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

thanks man!

Re: TH350 to 700R4
 

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.

Re: TH350 to 700R4
 

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

Re: TH350 to 700R4
 

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..

Re: TH350 to 700R4
 

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!

Re: TH350 to 700R4
 

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.