700r4

[fnny6770]

In a previous post it was mentioned that I should get a 700 r4 transmission and put in my truck, what would be the most cost-effective way to acquire one of these and to either rebuild it or ensure that it's in good working order?

 

[NickTransmissions]

In a previous post it was mentioned that I should get a 700 r4 transmission and put in my truck, what would be the most cost-effective way to acquire one of these and to either rebuild it or ensure that it's in good working order?

What previous post? Maybe link it to make it easy for folks to grab the context...

You need to provide a lot more info to get meaningful respones. Let's start with year, drivetrain type, intended application/usage pattern, engine power and go from there...

 

[fnny6770]

I don't quite understand how to link one of my posts that talks about the 700R4, to this post it's in one of my only three posts regarding my truck, I had to post about gears and what size differential gears may have came in my 1980 GMC 1 ton, my father ordered it from the factory with a 400 engine and a th400 transmission years later when my older brother inherited it he put the 454 in there with the four-speed manual, it's an older four-speed manual so all you have is granny gear plus three speeds and it seems like the engine's tachometer is pretty high at 55 mph, eats up a lot of fuel when going down the freeway. Somebody made the comment in this post about swapping over to a 700R4, if I could link this post to the one that talks about it which I'm sure there's a way you can do it but I don't know how, but I thought about maybe going to a gear vendor to speed overdrive but that seems like it'll be a little expensive

 

[Ricko1966]

I don't quite understand how to link one of my posts that talks about the 700R4, to this post it's in one of my only three posts regarding my truck, I had to post about gears and what size differential gears may have came in my 1980 GMC 1 ton, my father ordered it from the factory with a 400 engine and a th400 transmission years later when my older brother inherited it he put the 454 in there with the four-speed manual, it's an older four-speed manual so all you have is granny gear plus three speeds and it seems like the engine's tachometer is pretty high at 55 mph, eats up a lot of fuel when going down the freeway. Somebody made the comment in this post about swapping over to a 700R4, if I could link this post to the one that talks about it which I'm sure there's a way you can do it but I don't know how, but I thought about maybe going to a gear vendor to speed overdrive but that seems like it'll be a little expensive

Is this 2wd or 4 wd? On a 2wd big block with granny gear I'd be tempted to go 3.08 rearend,change nothing else and have almost the same gearing as a 700r4 on the highway. A 454 should have no problem pulling that,especially with a granny gear

 

[DoubleDingo]

Swap in 3.73 gears, 3.42 gears, it'll be easier and cheaper.

 

[fnny6770]

It's a 1980 GMC dual wheel k30, camper special my father ordered from the factory

 

[fnny6770]

I forgot to mention it has 410 gearing now in the differentials

 

[fnny6770]

Here's some pictures

 

[DoubleDingo]

700r4 will grenade under that truck. 4L80E is what you want for an auto trans. I stand by my previous post, swap gears and be done with it. Cheaper and better.

 

[Ricko1966]

@fnny6770 look what popped up on another thread.

 

[NickTransmissions]

I don't quite understand how to link one of my posts that talks about the 700R4, to this post it's in one of my only three posts regarding my truck, I had to post about gears and what size differential gears may have came in my 1980 GMC 1 ton, my father ordered it from the factory with a 400 engine and a th400 transmission years later when my older brother inherited it he put the 454 in there with the four-speed manual, it's an older four-speed manual so all you have is granny gear plus three speeds and it seems like the engine's tachometer is pretty high at 55 mph, eats up a lot of fuel when going down the freeway. Somebody made the comment in this post about swapping over to a 700R4, if I could link this post to the one that talks about it which I'm sure there's a way you can do it but I don't know how, but I thought about maybe going to a gear vendor to speed overdrive but that seems like it'll be a little expensive

Here's how I would have written your original post, with the link to the thread you were referring to:
----------------

In a previous thread (see link below), I discussed the possibility of changing my gears to something that would bring my engine RPMs down on the highway. I am also thinking of swapping a 700R4 into my 1980 GMC 1 ton truck. I currently have 4:10 gears and a three speed manual transmission which is putting me at over 3000 RPMs on the highway at 65 mph.

My question is what is the best way to go about obtaining a good working 700R4 or one for rebuild and are there any other overdrive transmissions that may be a better fit for my application?

Or should I change my final drive to a taller ratio to get the RPMs down on the highway?

My Gears thread for more context:

Gears

My 1980 GMC 1 ton truck came from the factory with four 10 gears 400 engine and a th400 tranny, my brother put a 454 in it with a three speed manual transmission and it seems like the differential gears are too high, my question is what size differential gears would have came with a manual...

www.gmsquarebody.com

--------------
See how much easier that is to read and respond to?

 

[fnny6770]

I'm very happy knowing that I was able to allow somebody to show the whole world how to properly word a series of questions for the answers of upcoming project, thank you!

 

[fnny6770]

I think everyone for your replies! The advice is priceless and seems a lot of headache with experimenting, I will look into getting some gears in the 308 range and hopefully that will make this truck very happy!

 

[fnny6770]

I'm not real sure the size of the camshaft in this truck, the way it idles it's definitely not stock, maybe I can talk to a crowler representative and explain what I got perhaps change the camshaft with lifters just to be on the safe side but the engine is very strong and it's not that old since it got rebuilt, my brother been inherited this truck as long since passed away so I can't ask him what he did to the engine

 

[Ricko1966]

I'm not real sure the size of the camshaft in this truck, the way it idles it's definitely not stock, maybe I can talk to a crowler representative and explain what I got perhaps change the camshaft with lifters just to be on the safe side but the engine is very strong and it's not that old since it got rebuilt, my brother been inherited this truck as long since passed away so I can't ask him what he did to the engine

Changing a Cam and Lifters is not simple or cheap task. Calling a cam manufacturer,they can't tell you what you have over the phone,and it's in their best interest to sell you a new cam. Put a tach in it, find out what rpm the truck cruises in without issues,still has enough power to mildly accelerate. That will tell you bottom of the scale for your cams usable rpm range. Now use an online calculator,punch in 3.08 gears, your 4th gear is 1/1 ,measure your tires and see if 3.08 has you in your rpm range. To cut cost until you are sure 3.08 is what you need just change the rear gears. Run in 2wd,or fronts hubs locked out,pull the front spider gears,whatever is applicable in your case to make the truck 2wd until you decide to do the front. In fairness to Nick for showing you how to write your post I couldn't answer your post on what you wrote initially,then after I had more info,then had to make assumptions and ask questions. You need to give pertinent details in the 1st post. Not expect everyone to hunt and search for your original post do we can see what you are working on.