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700R4 rebuild

Should I replace the weak but great running 2.8 V6 or swap it for a 3.4 V6?

  • YES

    Votes: 3 75.0%
  • NO

    Votes: 1 25.0%

  • Total voters
    4
  • Poll closed .

jcool

#78 A(ACLU) FNG
Messages
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Location
Richlands, NC
I am getting ready to rebuild a 87 700r4 to put in my 86 s-10 blazer 4x4 with a 2.8. Anyone have any advise, I will be doing it myself. So what special tools do I need? What components should I upgrade internally if any? Also on a side note, should I keep the 2.8 with 30k on it and zero issues or rebuild a 3.4 and swap it in along with the tranny?
 
I am getting ready to rebuild a 87 700r4 to put in my 86 s-10 blazer 4x4 with a 2.8. Anyone have any advise, I will be doing it myself. So what special tools do I need? What components should I upgrade internally if any? Also on a side note, should I keep the 2.8 with 30k on it and zero issues or rebuild a 3.4 and swap it in along with the tranny?

Justin I know nothing about rebuilding trannys but if you are going to swap engines why not go for the V6 4.3l I had a 98 S10 and gave it to my daughter. It's got 160k and still runs strong no issues. On the other hand if the 2.8 only has 30k it will prolly run for a long time! I think you could answer your own question on the engine by asking yourself what you are going to use it for and how much $$$ do you have to blow on it;)
 
Justin I know nothing about rebuilding trannys but if you are going to swap engines why not go for the V6 4.3l I had a 98 S10 and gave it to my daughter. It's got 160k and still runs strong no issues. On the other hand if the 2.8 only has 30k it will prolly run for a long time! I think you could answer your own question on the engine by asking yourself what you are going to use it for and how much $$$ do you have to blow on it;)

very true, I like the 4.3 but it is the same amount of wrenching to swap that in as a 350. Also the 3.4 is a direct swap for the 2.8 all the accessories from the 2.8 bolt onto the 3.4 and its the same motor mounts, so it will be almost like stock still. biggest change will be the 2.8 is a externally balanced engine vs the 3.4 internal balancing. its good for about 40-50 hp and tq but runs on mid-grade at least from what I have read.... also... I know nothing about trannies either... but there is only one way to find out!
 
very true, I like the 4.3 but it is the same amount of wrenching to swap that in as a 350. Also the 3.4 is a direct swap for the 2.8 all the accessories from the 2.8 bolt onto the 3.4 and its the same motor mounts, so it will be almost like stock still. biggest change will be the 2.8 is a externally balanced engine vs the 3.4 internal balancing. its good for about 40-50 hp and tq but runs on mid-grade at least from what I have read.... also... I know nothing about trannies either... but there is only one way to find out!

Hell yeah that's how you learn. I just put 4 wheel disc brakes, air bags, power steering box, all new suspension parts and had the 3rd member completely out from underneath the car. Put it all together and it works fine. I'm sure you can do the same with the tranny:thumbsup:
 
Hell yeah that's how you learn. I just put 4 wheel disc brakes, air bags, power steering box, all new suspension parts and had the 3rd member completely out from underneath the car. Put it all together and it works fine. I'm sure you can do the same with the tranny:thumbsup:


hell I thought you were a trained pro!!! sure looked like a great job you did on the nomad!!
 
Thanks! You can do the same my friend.....it just takes time and patience:D


something I am slowly grasping a concept of!!! I am reading the 700r4 overhaul manual and studying up prior to disassymbly... also helps to have a papa whom is the master of mechanics with 45+ years of experience standing behind me all the way! I really enjoy projects that give me some quality time with members of my family.... last weekend they were working on their will and it was really bothering me to think about that:frown5: anyway when we get a garage on this site post all the pics you got of your project!!
 
something I am slowly grasping a concept of!!! I am reading the 700r4 overhaul manual and studying up prior to disassymbly... also helps to have a papa whom is the master of mechanics with 45+ years of experience standing behind me all the way! I really enjoy projects that give me some quality time with members of my family.... last weekend they were working on their will and it was really bothering me to think about that:frown5: anyway when we get a garage on this site post all the pics you got of your project!!

I've been meaning to do just that at the DP I just need to resize the pics. Nothing beats spending time with you family. My grandfather and father are gone and I can't tell you how much I miss them! If they get the photo thing straightened out here I'll do it here.......
 
your question doesn't make sence "Should I replace the weak but great running 2.8 V6 or swap it for a 3.4 V6?" you can't answer that with a yes or no.
 
your question doesn't make sence "Should I replace the weak but great running 2.8 V6 or swap it for a 3.4 V6?" you can't answer that with a yes or no.

what I mean by that is that it is weak when it comes to power. but it still runs like a top. the 3.4 is a direct replacement and good for 40-50 more hp.
 
I did the 2.8 to 350 in my old '84 S10 a few years ago. It had the 2.8/5 speed and i went with a 350/700R4. Much better after that, I used the Advance Adapters motor mounts & headers. A '74 Nova 3 core radiator and ran duals out the back with magnaflow cats and 40 series flowmasters.
Used the Lokar "retro" hi stalk shifter, looked like it came in there after i was done AND passed emissions. Kewl.
Don
 
I did the 2.8 to 350 in my old '84 S10 a few years ago. It had the 2.8/5 speed and i went with a 350/700R4. Much better after that, I used the Advance Adapters motor mounts & headers. A '74 Nova 3 core radiator and ran duals out the back with magnaflow cats and 40 series flowmasters.
Used the Lokar "retro" hi stalk shifter, looked like it came in there after i was done AND passed emissions. Kewl.
Don

That sounds sweet! I saw a nice one the other day, 80's model, slammed nice paint and rims, looked cool!):h
 
I did the 2.8 to 350 in my old '84 S10 a few years ago. It had the 2.8/5 speed and i went with a 350/700R4. Much better after that, I used the Advance Adapters motor mounts & headers. A '74 Nova 3 core radiator and ran duals out the back with magnaflow cats and 40 series flowmasters.
Used the Lokar "retro" hi stalk shifter, looked like it came in there after i was done AND passed emissions. Kewl.
Don

That sounds awesome! Do you still have the truck?
 
The 700R4 isn't too difficult of a transmission. It isn't one I would tell a first timer to do though. Get an ATSG manual. If your father is a master tech, make sure he is there by your side. You're going to have a lot of parts in front of you once it is disassembled! Definitely get a hardened sunshell while you are in there. I would also do a Transgo in it. These are above and beyond your typical rebuild parts. You're obviously going to went to get a master kit and converter. Don't forget a pump bushing, actually on something that old a full bushing kit wouldn't be a bad idea. I would also upgrade the sprags as well.
 
The 700R4 isn't too difficult of a transmission. It isn't one I would tell a first timer to do though. Get an ATSG manual. If your father is a master tech, make sure he is there by your side. You're going to have a lot of parts in front of you once it is disassembled! Definitely get a hardened sunshell while you are in there. I would also do a Transgo in it. These are above and beyond your typical rebuild parts. You're obviously going to went to get a master kit and converter. Don't forget a pump bushing, actually on something that old a full bushing kit wouldn't be a bad idea. I would also upgrade the sprags as well.

Thanks for the input! if I order a master rebuild kit the items you mentioned don't come with it? should I just use a stock rebuild with the transgo? I am not intending on puting a lot of power to it but want it tough...
 
i would be asking what small diesel can i slide in there to get some great mileage. lots of small diesels out there. how bout a mercedes 300d five cylinder. or a 4bt cummins or a izusu. you will have no problems with rebuilding a 700r4 just don't just mix parts like springs or valves , when you tear it down keep the parts in order on a bench so you can do the rebuild a section at a time. good luck , keep it clean. and at least do the -1 transgo i love it in our suburban.
 
i would be asking what small diesel can i slide in there to get some great mileage. lots of small diesels out there. how bout a mercedes 300d five cylinder. or a 4bt cummins or a izusu. you will have no problems with rebuilding a 700r4 just don't just mix parts like springs or valves , when you tear it down keep the parts in order on a bench so you can do the rebuild a section at a time. good luck , keep it clean. and at least do the -1 transgo i love it in our suburban.

the plan is to put a 4bta in it eventually, but i am going to keep the 2.8 for now since the 3.4 i was looking at needs more than a rebuild(was in a crash) I want to make the 700r4 stout so i can just swap the 4bta in place of the 2.8(sounds good in theory) since advance adaptors has a adaptor to mate the two together. all and all i was returning 26-27mpg on the highway with the 2.8 in top running order and will keep it that way till i learn more about the 4bta and get everything together to swap it over in a short amount of time. everyone i know that has done the 3.4 swap loves the power but has to run mid-grade gas and is lucky to get 18-20mpg.... so i decided to save up for the 4bta once again..... the only person i know with a diesel in his s-10 has the factory 85 2.2, its slow, noisy and ugly but returns low 30mpg figures in his 4x4 rig and mid 20's in the city.... :cornut:
 
I rebuilt a 700R4 in my 83 3/4T GMC.

It wasn't too hard for my second Auto trans rebuild. You do need a few tools for dis assem and assemblely for spring compression. I made my spring compressor from some steel bar and ready rod.

A good manual is a must. I found the Haynes GM trans overhaul to be pretty good.

One of the things that may not be clear in the manual, lube the seals with petroleum jelly and carefully tuck them into place with a feeler gauge blade as pistons are inserted. Make sure to not fold the seal over during assembly. Watch the feeler gauge, don't cut the seal lip.

Lastly, Air Check each assembly. Leaks are easier to fix as you assemble than taking the trans back out.

Pay attention, go slow, double check. It should go well.

Good luck,
 
I rebuilt a 700R4 in my 83 3/4T GMC.

It wasn't too hard for my second Auto trans rebuild. You do need a few tools for dis assem and assemblely for spring compression. I made my spring compressor from some steel bar and ready rod.

A good manual is a must. I found the Haynes GM trans overhaul to be pretty good.

One of the things that may not be clear in the manual, lube the seals with petroleum jelly and carefully tuck them into place with a feeler gauge blade as pistons are inserted. Make sure to not fold the seal over during assembly. Watch the feeler gauge, don't cut the seal lip.

Lastly, Air Check each assembly. Leaks are easier to fix as you assemble than taking the trans back out.

Pay attention, go slow, double check. It should go well.

Good luck,


Thanks... so as of now what I am getting is that I should use a stock rebuild with a transgo shift kit?
 
The 700R4 isn't too difficult of a transmission. It isn't one I would tell a first timer to do though. Get an ATSG manual. If your father is a master tech, make sure he is there by your side. You're going to have a lot of parts in front of you once it is disassembled! Definitely get a hardened sunshell while you are in there. I would also do a Transgo in it. These are above and beyond your typical rebuild parts. You're obviously going to went to get a master kit and converter. Don't forget a pump bushing, actually on something that old a full bushing kit wouldn't be a bad idea. I would also upgrade the sprags as well.

I used a master kit. I asked my local trans guy about a shift kit for the 700r4 and he said it really wasn't needed, but follow ChampionTransmission suggestions.
 
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