Since this thread is older, I'm curious if you went ahead with the swap?
I swapped my 350 out for a 700r4 in '21 so if you haven't already done it, i can answer questions if you have any.
CK5
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72 K5 Blazer 700r4 upgrade
- Thread starter PompUOP
- Start date
I swapped my 350 out for a 700r4 in '21 so if you haven't already done it, i can answer questions if you have any.
rampage
3/4 ton status
His last login was over 3 yrs ago so I doubt you’ll get an answer.
I wasn't counting on it, but thanks for the heads up. His loss. There's metric S*** ton of information on this network !
No, we generally work in SAE units here
No, we generally work in SAE units here
i don't get it
I have this done to my 1977 blazer I just purchased and I most definitely have questions. It's a 400 sbc with the 700r4. Like it when I bought it. The front driveshaft isn't installed yet but I have it. And the transfer case shifter isnt installed either. How did you go about attaching the shifter? Did you use the same linkages or did you use a different linkage.
Also how did You hook the odometer back up? I haven't sized that part up yet. Did it just plug back in or did you need an adaptor?
What did you do about this OD issue everyone was discussing?
Welcome to CK5 @r3bartl
The t case shifter depends on which t case you have. Np205 should bolt to the adapter. the part between trans and t case, and have the mount to cross member. Np203 iirc bolts to the trans hump in truck.
There is also the issue of how your trans output shaft is done, The 700r4 was never offered with either the np203 or the np205. The out put shaft is to long to bolt up a th350 adapter and tcase. With the factory output there is a spacer piece, https://www.offroaddesign.com/700r4-spacer-1-7-8-inch-with-bolts.html
This piece moves your t case back. Moving the t case, make the rear drive shaft angles tighter, and the front driveshaft better, both driveshafts will need length adjusted. Also the shifter for the np205 will be moved back almost to the center consul. Many would use an after market twin stick shifter kit. This will allow the use of cables. This option will work for a np203 as well.
The second method to mate a 700r4 to either t case is https://www.advanceadapters.com/output-shaft-stock-700r4-4x4-1325, this output shaft allows the use of th350 mated directly to the 700r4. This move the t case and adapter 1.75" back. The shifter opening can be enlarged to allow the stock np205 shifter to be used. the rear drive shaft should be shortened 1.75". With this method the front drive shaft can be very troublesome, for either of these two t caes. There isn't a lot of room to clear the trans pan. In my case 1991 700r4 mated to a 1972 np205 I need to use the double cardan 1310 spicer yoke shaft. It is very close but clears. This isn't a strong shaft, but is good enough for my needs.
This is a lot, I am sure you have questions. Please ask any and all, we will do our best to explain.
The t case shifter depends on which t case you have. Np205 should bolt to the adapter. the part between trans and t case, and have the mount to cross member. Np203 iirc bolts to the trans hump in truck.
There is also the issue of how your trans output shaft is done, The 700r4 was never offered with either the np203 or the np205. The out put shaft is to long to bolt up a th350 adapter and tcase. With the factory output there is a spacer piece, https://www.offroaddesign.com/700r4-spacer-1-7-8-inch-with-bolts.html
This piece moves your t case back. Moving the t case, make the rear drive shaft angles tighter, and the front driveshaft better, both driveshafts will need length adjusted. Also the shifter for the np205 will be moved back almost to the center consul. Many would use an after market twin stick shifter kit. This will allow the use of cables. This option will work for a np203 as well.
The second method to mate a 700r4 to either t case is https://www.advanceadapters.com/output-shaft-stock-700r4-4x4-1325, this output shaft allows the use of th350 mated directly to the 700r4. This move the t case and adapter 1.75" back. The shifter opening can be enlarged to allow the stock np205 shifter to be used. the rear drive shaft should be shortened 1.75". With this method the front drive shaft can be very troublesome, for either of these two t caes. There isn't a lot of room to clear the trans pan. In my case 1991 700r4 mated to a 1972 np205 I need to use the double cardan 1310 spicer yoke shaft. It is very close but clears. This isn't a strong shaft, but is good enough for my needs.
This is a lot, I am sure you have questions. Please ask any and all, we will do our best to explain.
Thanks for the welcome.Welcome to CK5 @r3bartl
The t case shifter depends on which t case you have. Np205 should bolt to the adapter. the part between trans and t case, and have the mount to cross member. Np203 iirc bolts to the trans hump in truck.
There is also the issue of how your trans output shaft is done, The 700r4 was never offered with either the np203 or the np205. The out put shaft is to long to bolt up a th350 adapter and tcase. With the factory output there is a spacer piece, https://www.offroaddesign.com/700r4-spacer-1-7-8-inch-with-bolts.html
This piece moves your t case back. Moving the t case, make the rear drive shaft angles tighter, and the front driveshaft better, both driveshafts will need length adjusted. Also the shifter for the np205 will be moved back almost to the center consul. Many would use an after market twin stick shifter kit. This will allow the use of cables. This option will work for a np203 as well.
The second method to mate a 700r4 to either t case is https://www.advanceadapters.com/output-shaft-stock-700r4-4x4-1325, this output shaft allows the use of th350 mated directly to the 700r4. This move the t case and adapter 1.75" back. The shifter opening can be enlarged to allow the stock np205 shifter to be used. the rear drive shaft should be shortened 1.75". With this method the front drive shaft can be very troublesome, for either of these two t caes. There isn't a lot of room to clear the trans pan. In my case 1991 700r4 mated to a 1972 np205 I need to use the double cardan 1310 spicer yoke shaft. It is very close but clears. This isn't a strong shaft, but is good enough for my needs.
This is a lot, I am sure you have questions. Please ask any and all, we will do our best to explain.
That is a lot of information and I've learned I need to dig into what the previous owner has done to mate the two together. I also need to know what transfer case I have. Might make sense now why the front driveshaft was never installed lol.
Thanks for the information and ill be back when I learn some more lol.
Post up some good pictures of your transfer case and we can identify it for you.
And welcome aboard!
Hey Tarussell dumb question but how do you add picture on this forum. seems to be all URLs?
Oh, I’m the wrong one to ask on the ins-n-outs of adding pictures - the only way that I know how is to click on the “attach files” button and go to the picture storage section and select.
There is some kind of rule that you must have about a half-dozen posts before pics can be posted - I think it’s to keep them ISIS terrorists away.
Somebody that knows what they’re talk’n about will chime in and help.
My knowledge stops at the mechanical stuff.
there's a minimum post requirement. The easiest way is to pay the gate fee, and then stick around
There's an entire other half of this forum that it will allow you to access
OK well I'll just have to keep posting till i reach the limit lol. I don't think we got to many isis terrorists in Canada, we just got a lot a rust lol.
I'll probably end up doing that. I feel like what I have bought is going to be a project and this 700r4 is going to be a pain lol.
there's people here who can help. Sometimes it's even me!
many times
So this is my issue I believe. I have the 700r4 matted to a 400 sbc. I'm not sure exactly how he matted the transfer case to the 700r4. But the transfer case is pushed closer to the rear diff now. Obviously making the rear drive shaft shorter and front drive shalft longer. My truck is not lifted but has 33inch MT just for reference.
I need a new drive shaft because they welded the old one together at the slip. Only reason I can see they did that was so it wouldn't slip out? Anyways. The biggest two issues I have right now besides maybe some internal rear end damage? Would be
1. The linkage for the transfer case. It's an aluminum case so I'm assuming it's the np203. When I can post pictures I will. I think I'm going to fab up a twin stick setup. I want to keep it in the factory location. I found offroad designs twin stick instalation guide and looks easy enough to make.
2. The biggest issue is the front driveshaft won't clear the cross member for the transfer case. Looks like I might need a custom driveshaft? Or is there a better crossmember design out there that'll help with clearance issues?
Oh and she's an electronic 700r4. So how have people been getting her into OD? I think some people on this forum have been using a switch?
This is also my first square body so I'm trying to learn stuff as quick as I can. So if I gets something wrong bare with me lol
The t cases start from the factory with a tag on them. Originally that truck was a NP203 (probably since it was an automatic)
The NP203 is an all iron t case
Originally, a NP241 would have been married to that 700r4 (maybe a NP208, but those two are almost interchangeable) this is probably what you have
That will give you some numbers to look up in google photo until you find a tag or can post pictures
The factory automatic in 1977 would have been a 3 speed automatic. If the shifter is the column shifter, it’s likely you are pulling the transmission into 3rd, thus locking it out of 4th - OD
1- the ORD shifter is great. It’s not free, but works awesome. The 208/241 shifter will be a cable driven unit, also available is a JB conversions unit
2- finding a crossmember from a newer application that had the 700/241 application may be the ticket, or build your own…
3- the switch you are think of is probably for the torque converter lockup. It will lock/unlock depending on speed or throttle. You can also run it as a toggle, but I would recommend a vacuum operated switch
Lastly…
Does the aluminum t case have a place for a cable, or is it an electric connection the the output (for the speedo)?
Once you figure some of these issues, you can approach the driveshaft resolution. There may be a junkyard nearby that you can source and original driveshaft instead of popping for a new one
Welcome to the board! Looks like you got yourself some work to do!
The NP203 is an all iron t case
Originally, a NP241 would have been married to that 700r4 (maybe a NP208, but those two are almost interchangeable) this is probably what you have
That will give you some numbers to look up in google photo until you find a tag or can post pictures
The factory automatic in 1977 would have been a 3 speed automatic. If the shifter is the column shifter, it’s likely you are pulling the transmission into 3rd, thus locking it out of 4th - OD
1- the ORD shifter is great. It’s not free, but works awesome. The 208/241 shifter will be a cable driven unit, also available is a JB conversions unit
2- finding a crossmember from a newer application that had the 700/241 application may be the ticket, or build your own…
3- the switch you are think of is probably for the torque converter lockup. It will lock/unlock depending on speed or throttle. You can also run it as a toggle, but I would recommend a vacuum operated switch
Lastly…
Does the aluminum t case have a place for a cable, or is it an electric connection the the output (for the speedo)?
Once you figure some of these issues, you can approach the driveshaft resolution. There may be a junkyard nearby that you can source and original driveshaft instead of popping for a new one
Welcome to the board! Looks like you got yourself some work to do!
Forgot to mention the TV cable. There should be a cable from the transmission hooked to the bottom side of the carburetor. It does magic transmission things. If it is adjusted wrong it will cause doom and malcontent in the transmission
I’ll look for a good video on how you adjust that
I’ll look for a good video on how you adjust that
If you have a 208 or 241 T-case, you won't be able to use a twin stick shifter. There's only one lever on the case. The factory shifter for both of those bolts to the floor and uses a rod to connect to the lever on the case.
Both of those cases use a slip yoke that slides on the output shaft of the T-case, so the drive shaft is solid.
A 700R4 will go into OD when the valve body and governor commands it. It doesn't require an electrical signal.
The electrical plug on the left side is only for the torque convertor lock-up. You do want to make sure that it is locking the convertor when in OD, otherwise it builds too much heat and I have been told that it won't cool properly because of the oil flow internally.
It may not need the electric signal depending on if someone did a hydraulic conversion in the valve body. Does yours have any wires going into the plug?
Both of those cases use a slip yoke that slides on the output shaft of the T-case, so the drive shaft is solid.
A 700R4 will go into OD when the valve body and governor commands it. It doesn't require an electrical signal.
The electrical plug on the left side is only for the torque convertor lock-up. You do want to make sure that it is locking the convertor when in OD, otherwise it builds too much heat and I have been told that it won't cool properly because of the oil flow internally.
It may not need the electric signal depending on if someone did a hydraulic conversion in the valve body. Does yours have any wires going into the plug?
