4x4 Blazer manual to 700r4 swap

[My7d1]

Very long story short, as of today I am the proud owner a new 700r4 for a 4x4. Next week I am planning on changing out the stock 4 speed in my Blazer to the 700r4 and have a few questions I am hoping someone can help answer to make it a smooth swap.

I had planned on doing the same swap on my 2 wheel drive C-10 and had bought the correct crossmember and mounting pad, the 700r4 never went in and I still have the crossmember and pad, will this same crossmember work on the 4x4?

Besides the new steering column with the shifter, the transmission, the torque converter, dipstick/tube & the crossmember what will I need? Flexplate? Trans cooler? New neutral safety switch? Anything "special" needed to connect to the transfer case?

I assume a shifter conversion kit will be needed so the column shifter actually changes the gears, i see 2 options online for universal kits, the difference in the 2 options is for the length of the shaft, any reason not to get the the longer and trim if needed?

Last one - Removing the actual clutch pedal? I don't even know where to start on that one!

THANKS as any and all input is appreciated!

[A1971Blazer]

The biggest hurdle will be adapting the transmission to the transfer case. You will have to have the 700R4 output shaft changed to a 27 spline and use a 350 turbo adapter and special coupler to mate to the 10 spline input shaft on the TC.
Or you can change the input shaft on the TC to 27 spline as well and use a 27 spline coupler.
Or you could source a NP241 passenger side drop transfer case that would mate to the 700R4.

As far as the clutch pedal, both the brake and clutch pedal are mounted to the same bracket. I'm doing a swap on my '71 with a 4L60E, what I plan on doing is simply cutting the clutch pedal off up close to the bracket and forget about it.

For the cross member, I haven't gotten that far because I am also swapping in a LS1 motor at the same time.
I plan on just making one or modifying the factory crossmember.

You will need the auto steerng column and I think someone makes a linkage kit, Lokar maybe, that can be cut to fit.
You may need to change the lever on the tranny to get it to shift properly.

[My7d1]

Originally Posted by A1971Blazer

The biggest hurdle will be adapting the transmission to the transfer case. You will have to have the 700R4 output shaft changed to a 27 spline and use a 350 turbo adapter and special coupler to mate to the 10 spline input shaft on the TC.
Or you can change the input shaft on the TC to 27 spline as well and use a 27 spline coupler.
Or you could source a NP241 passenger side drop transfer case that would mate to the 700R4.

As far as the clutch pedal, both the brake and clutch pedal are mounted to the same bracket. I'm doing a swap on my '71 with a 4L60E, what I plan on doing is simply cutting the clutch pedal off up close to the bracket and forget about it.

For the cross member, I haven't gotten that far because I am also swapping in a LS1 motor at the same time.
I plan on just making one or modifying the factory crossmember.

You will need the auto steerng column and I think someone makes a linkage kit, Lokar maybe, that can be cut to fit.
You may need to change the lever on the tranny to get it to shift properly.

Thanks for the info! Was hoping the 700r4 would just slip into the TC since it is specifically for a 4x4, I should've known, its rarely that simple...

Wondering if the old 4 speed would have any resale value?

[A1971Blazer]

Originally Posted by My7d1

Thanks for the info! Was hoping the 700r4 would just slip into the TC since it is specifically for a 4x4, I should've known, its rarely that simple...

Wondering if the old 4 speed would have any resale value?

You could perhaps sell it locally, the problem is they are as heavy as a boat anchor.....shipping is truck freight only also they're fairly plentiful, at least here.
I have two or three myself.

[jjzepplin]

As mentioned above you will need all the correct adapters. The th350 adapter is getting pricey but Advance Adapters makes a reproduction. They also used to make a coupler with the 10 spline on one side and the 27 on the other. I don't know how well they hold up but I have had several 10 spline 4 speed units that got loose inside the coupler. Never on the 27 so If it were me I would change the case input or trade yours in for one already done.
I would also look into replacing the whole cab wiring harness with an auto style. Not hard to do and can be had on this site for $50 or so shipped.
The clutch pedal can simply be removed from the pedal assembly. Look up inside and you will see that. No cutting is necessary.
Column- Also can be had on here with auto linkage on the cheap.
SOOO- all these things are needed and can be done but it takes time=lots of time to do it right.
I just finished my 4x4 swap not long ago a year or so and am shizzle tons happier with the 700r4.
The granny was great for launching the boat but I have a crawl box on my auto and with the slip of a lever I have a darn low gear to pull anything.

[My7d1]

Originally Posted by jjzepplin

As mentioned above you will need all the correct adapters. The th350 adapter is getting pricey but Advance Adapters makes a reproduction. They also used to make a coupler with the 10 spline on one side and the 27 on the other. I don't know how well they hold up but I have had several 10 spline 4 speed units that got loose inside the coupler. Never on the 27 so If it were me I would change the case input or trade yours in for one already done.
I would also look into replacing the whole cab wiring harness with an auto style. Not hard to do and can be had on this site for $50 or so shipped.
The clutch pedal can simply be removed from the pedal assembly. Look up inside and you will see that. No cutting is necessary.
Column- Also can be had on here with auto linkage on the cheap.
SOOO- all these things are needed and can be done but it takes time=lots of time to do it right.
I just finished my 4x4 swap not long ago a year or so and am shizzle tons happier with the 700r4.
The granny was great for launching the boat but I have a crawl box on my auto and with the slip of a lever I have a darn low gear to pull anything.

Well, I now have everything except the coupler and or the adapter. Thanks for the hook-up on Advance Adapters, checked their web-site and will call them tomorrow to place the order. Then once its in I too will be "shizzle tons happier"! I know the drive will become better/smoother but how did it do on gas mileage? Was there noticeable difference/improvement??

Thanks again!

[franken]

You may want to post a pic or two of the back of the new trans so we can see if an adapter is still bolted to it.

[jjzepplin]

EVERYTHING is different. Not really fair to compare the two setups really.
I drove it from Cali back in 2001 when the setup was in my Blazer (prior to the wreck) and with at least a ton of stuff in the back and on the hitch hauler and strapped to the top, I got about 15 mpg on average for the 3000 mile trip.
Do yourself a favor and get a real good converter. This for me was the weak link. I had one custom built for a couple hundred after blowing up a TCI. The fella that built mine cut the TCI open in front of me and pointed out that it was nothing more than a stock converter. After I replaced it and went through the tranny once more I replaced the pump with a 13 vane ART CARR unit and all has been fantastic since.
Seems the lockup part of the converter just exploded.
The new unit has been there for a decade and the fella said he put a seriously thicker lockup clutch in there.
Tows the boat fine and soon will be towing a 20 foot trailer with butt loads of wood on it and the occasional vehicle. Though when towing you never use the lockup or overdrive 4th gear.

[My7d1]

Originally Posted by franken

You may want to post a pic or two of the back of the new trans so we can see if an adapter is still bolted to it.

Some pics of the new 700r4 tail

[franken]

No adapter
You can go to advance adapters and download their conversion guide. Also have a look on ebay and search for np205 27 spline input. It looks like you need the 205 27 spline input, a coupler, and the 4 bolt 700R to NP205 8 bolt adapter.

I guess your TC is an NP205 since the truck seems to be 71/72.

[My7d1]

Originally Posted by franken

No adapter
You can go to advance adapters and download their conversion guide. Also have a look on ebay and search for np205 27 spline input. It looks like you need the 205 27 spline input, a coupler, and the 4 bolt 700R to NP205 8 bolt adapter.

I guess your TC is an NP205 since the truck seems to be 71/72.

Nope, no adapter, called and talked to Advance Adapters, quick and fairly painless except the cost for the "kit", have to say they sent it very quickly... The weird thing is the guy from Advance said I would have to change both drive shafts as well? I realize the original and new transmissions are different lengths requiring the new crossmember but shorten the rear drive shaft and lengthen the front? Does that mean the TC gets relocated because of the extra length of the 700r4?

and yes its the NP205 TC

[jjzepplin]

Yes that is correct. Just lengthen and shorten the existing ones. My local guy did mine both for $150 balanced.
I moved the case back and lowered it a bit while I was at it to lessen the angle to the differential.