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Overdrive Trans for 75 Blazer w/203 and 350 trans

S

scp1scp1

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As gas continues to go up, I have finally decided to look at putting in the overdrive transmission. Question is, which one? I do not want to put in a computer assisted tranny if I do not have to. Is there a thread already on here to help with the installation, such as having to change the crossmember, etc. Any assistance helps. Thanks, Steve.
 
The least expensive would prolly be the 700r4 you can beef them up, but stock they should do ok if you dont tow too much, summit racing sells some new ones
 
I use the Blazer mostly on the road, occassionally pulling a small trailer, and the four wheel drive is used in snow weather here in Indiana which is not often. Anyone know someone who has done this? Looking for hints on the crossmember and the transfer case mounting. I understand the driveshaft will need to be modified. Thanks, Steve.
 
You're best bet is probably the 700r4. An nv4500 is also overdrive but a manual tranny if you want to go that way.
 
bp71k5 said:
You're best bet is probably the 700r4. An nv4500 is also overdrive but a manual tranny if you want to go that way.
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Couldn't he just yank the 700R4, NP208 and driveshaft from a mid-to-late-80's K5, grab the crossmember while he's under there, and call it good?
 
Couldn't he just yank the 700R4, NP208 and driveshaft from a mid-to-late-80's K5, grab the crossmember while he's under there, and call it good?
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Sure. The only downside might be losing the np205. If overdrive is the goal, the 700r4 should bolt right up in place of the th350 after moving the crossmember back a little. He can keep the x-case he has.
 
bp71k5 said:
Sure. The only downside might be losing the np205. If overdrive is the goal, the 700r4 should bolt right up in place of the th350 after moving the crossmember back a little. He can keep the x-case he has.
Click to expand...

He has an NP203...

:deal:
 
just put a 700r4/208 combo in my 74 blazer, u will need a controller for the torque convertor though, i put in fuel injection at the same time so i didnt need that, but i believe summit has the controller for it, but if i were u i would just get a tbi set up as well so much better on gas than my carbed engine, by the way your going to need a different bracket for the tv cable its different than that of the detent cable, along with the driveshafts, crossmember. Id go with a 208 over the 203 too, the full time xcase is not so good for economy either. also look into putting lockouts into the front axle, everything helps less moving parts the better.
 
chevyuser74 said:
just put a 700r4/208 combo in my 74 blazer, u will need a controller for the torque convertor though, i put in fuel injection at the same time so i didnt need that, but i believe summit has the controller for it, but if i were u i would just get a tbi set up as well so much better on gas than my carbed engine, by the way your going to need a different bracket for the tv cable its different than that of the detent cable, along with the driveshafts, crossmember. Id go with a 208 or the 203 too, the full time xcase is not so good for economy either. also look into putting lockouts into the front axle, everything helps less moving parts the better.
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My 700R4 was modded with a non-electronic lockup, or something... I know it's not wired in as it was originally.
 
also drilling new holes into the frame sucks, so make sure to have good drill bits, and had to use the newer crossmember cause the old one woudnt work. had to make a new exhaust pipe to make it work though, just the driverside the pass still worked out. Make sure u adjust the tv cable right or the trans will take a ****, its not just a downshift cable on it, it controls the shifting. I also put in a trans cooler when i put mine in heat and the 700r4 are not friends, also trannys built before 88 (i think thats right) i would stay away from they are more prone to problems, unless they were rebuilt then most likely they got the updates they needed.
 
jonrpick said:
My 700R4 was modded with a non-electronic lockup, or something... I know it's not wired in as it was originally.
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ya, ive heard about that, if u have it rebuilt they can install something so the hydrallics contol the torque convertor, the trans shop here mentioned that when i had mine rebuilt
 
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