turbo 400 to 700r4 swap......should i do it?

[Wracks81]

my longbed has a rebuilt turbo 400 in it right now. I would love to have overdrive in it,and my Camaro has a 700r4 that is coming out for a manual. should I swap in the 700r4 or leave it?! 2wd longbed,not auto-x racing it or anything,just a cruiser. what can I expect on durability?

 

[yevgenievich]

Sell 700r4 and buy a gear vendors unit to put behind the th400 if going for capability and durability. Both options would need a new drive shaft regardless. 700r4 works fine for a cruiser, but It is a weaker transmission unless built well.

 

[74 Shortbed]

I second the GearVendor if you're gonna be hauling loads or towing, for just going down the road a 700R with a few mild upgrades will work just fine, but only if the 700 is 87 and newer, if not then send it down the road and bolt in a GearVendor and forget about it,you can do whatever you want with it then.. And since you have a TH400 now all you'll need to do is shorten the driveshaft and you're good to go.

 

[Wracks81]

Sell 700r4 and buy a gear vendors unit to put behind the th400 if going for capability and durability. Both options would need a new drive shaft regardless. 700r4 works fine for a cruiser, but It is a weaker transmission unless built well.

Not gonna be towing anything,just a driver/cruiser. Maybe a burnout here and there! Trans will be out of a 91 camaro.

 

[yevgenievich]

Not gonna be towing anything,just a driver/cruiser. Maybe a burnout here and there! Trans will be out of a 91 camaro.

As long as there is a budget for a rebuild when the 3-4 clutch pack burns up it would be ok. I am putting one in my 67 camaro, but it is a lighter vehicle. It should be ok, just not much towing

 

[TIE_Fightertk06]

I just did this swap on my R2500 Suburban...
Did a monster in a box rebuild on a 700R4, used TCI’s constant pressure valve body and a stock converter. Have a nice cooler with a dedicated thermostat controlled fan.
It’s a nice transmission, and I’m sure it’ll last, but honestly I’m not as happy as I thought I’d be. I have 3.73s in the rear and it’s fine on the road, but still not where I want it.
I was in the same boat, happy with the 400 but wanted OD. If I could go back, building my 400 and adding a GV over/under would have been a better investment of time and money. It also would have forced my hand in going with a 1-piece DS immediately, but that’s another story. Anyway, you get all the awesomeness of the TH400, plus the stone cold reliability and capability of the GV over/under when you want it.

As it stands, my two-year plan is a 6L80, Allison 1K, or building another TH400 with a GV over/under once I decide on an engine.

But hey, I’ve always had standards in my GMs until this Suburban, so I was looking at the 700R4 from just a gearing point of view. I had never owned a vehicle with one. If you like the characteristics of the 700R4 in your camaro, match the rear end gearing in your pickup, and toss that 700 in there. They can be built to fix all the factory fails now for reasonable money.

 

[shiftpro]

With any over drive transmission you need to gear down. You can't lug your truck on the highway expecting to see fuel savings.

The 700 is not a cheap transmission to rebuild let alone beef up. Not like a TH400 that's for sure.

You would like the lower 1st gear the 700 offers!

 

[yevgenievich]

I put 700r4 in my old short bed truck and it was instant burn out machine with the low first gear. But it also blew up 3-4 clutch pack within a week. Was stock out of a 180k mile burb

 

[Hollywoodk10]

I have a complete set-up 700r4 (has np205 output) advanced adapters adapter and can even include the np205...700r4 is a high impact transmissions setup for 500hp, has lock-up converter, lokar nostalgia shifter...transmission has about 4000 miles on it...worked awesome...decided to go a dif way with truck...I did have to gear down because the engine would lug and my edelbrock carb secondaries would open and you could watch the fuel gauge go down....I spent about 3500 on all this new....if you are still interested we could make a deal....front driveshaft with dual cardan type is a squeeze for sure but does fit...

 

[80goldenburb]

do it! i got rid of the dinosaur th400 that was behind the previous engine in my suburban. i had a 500 lb ft torquer 502 at the time. it was only a cruiser, i never gave it full throttle in fear of trashing the 700 when i got it in there.

 

[1980Spartan]

I'm looking at doing the same. I have a TH350 in my 1980 and will probably go to a 700R4. Having the OD is huge for me. The freeways where im at are all 70mph.

Although a lot of guys have had issues, when they get into their story about what happened they generally fried a stock transmissions with some miles on it. There's nothing wrong with that, cause everyone is working on a budget and honestly, if it's a project fun truck, swapping stuff in and out to see what you like best is where the fun is at!

As for prices, you can get a TH400 rebuilt at higher horsepower ratings than 700R4s for significantly cheaper. That being said, we're talking about an extra 600-700 dollars to get what YOU want, that being a 700R4 that can handle more power.

 

[Derick C.]

I tow a 5k lb enclosed trailer very often in the summer with a 454 in front of my 700r4, it does a great job.

 

[74 Shortbed]

I'll be putting a big block in the Burb and it'll have a 700 behind it..

 

[4WDKC]

Have a Bowtie overdrives 700r4 stage 3 in my vette and a stock ish 700r4 in my V10, when either quits they will not be going back in. If it were me Id sell the 700 and the 400 go find a working 4l80 and 0411 ecm then convert it to a stand alone controller and be done with it.

 

[84 M1008]

An R4 from a Camaro? It'll be toast in no time. Get the GV. A stage 2 R4 isn't $1300.00 transmission. I looked into a stage 2 super duty for about $3200.00 without a core. That 400 is a superior transmission to the R4 hands down.