TH350 to 700R4

[big dump]

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.

[Thealien]

interested also

[big dump]

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

[Arizonak5]

pm sent !

[vtblazer]

Originally Posted by big dump

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.

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

[big dump]

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

[big dump]

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.

[AJs72K5]

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.

[vtblazer]

Originally Posted by big dump

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.

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.

Originally Posted by AJs72K5

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.

Here's what AJ is talking about:
The 205 has a pretty enemic 1.96:1 low range compared to the 2.72:1 of the 241 t-case.
...and as stated, the swap is easier/less bucks.

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.

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.

[big dump]

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..

[pumpkin]

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.

[big dump]

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.

[AJs72K5]

Originally Posted by big dump

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.

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.

[vtblazer]

Originally Posted by AJs72K5

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.

Gotta agree with AJ, nice dissertation dude.

[big dump]

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..

[vtblazer]

Originally Posted by big dump

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..

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.

[big dump]

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

[OldCreek]

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

[big dump]

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.

[OldCreek]

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!

[big dump]

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..

[big dump]

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...

[JMac11]

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.

[big dump]

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..

[BobbyK]

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.



Here it is on their site.


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.




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.




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