About ready to start a 3.4 Swap

Dirtoy4x4 · 07-25-2009, 03:53 PM

Hi All,

I'm about to embark on a 3.4 swap and wanted to post this up in case there is something I am overlooking.

My truck is a 94 3.0 Auto (a340h) and I'm about to swap in a 97 3.4 T100 (auto) engine in place of the 3.slow. I have read through the threads many times over the years but just wanted to run this past "the experts" as to what I should expect or in case there is something I'm forgetting.

Engine & Transmission
As i understand it, the 97 3.4 Auto T100 engine will bolt right in place of the 3.0 and the ECU will control my A340H transmission. Any issues with the A340H hydraulic transfer case?

Exhaust
I am planning to use Downey 3.4 Headers, I have read that these are hard to come by and am hoping to pick up a set. On the Downey website it mentions that the headers interfere with a body lift (my truck has a 3") but I'm going to give them a call Monday, as I'm hoping this is only applicable to vehicles originally equipped with the 3.4 (Tacoma / 3G Runner / T100)? Other than building a crossover, are there any other 3.4 headers that will work with this swap if i can't source the Downey's? I already have the ceramic 3.0 headers so the rest of my exhaust is already setup for headers.

Misc..
Anything funky about the 97's 3.4's I should be aware of? I'm not planning to supercharge the engine, just want a little more power and the 3.4 reliability.

Anything else I should be aware of (besides the wiring)?

Much Appreciated!
-Stephen

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dntsdad · 08-03-2009, 08:02 AM

not sure on some of your other questions but I did see a few pair of Downeys on the Pirate4x4 classifieds if its not too late.

Good luck and make a thread noting your work/problems.successes/ideas basically everything for those of us going to take this on in the future.

Best of luck

yodathespian87 · 08-03-2009, 10:50 AM

Other things to be aware of...

Oil Pressure sender swap
oil pickup tube and pan swap.
engine mount brackets
wiring
battery tray moved to drivers side
thats about it.
Good Luck and keep us posted

Dirtoy4x4 · 08-05-2009, 12:25 PM

Thanks for the help guys.

I have a bit of a dilemma. I'm trying to decide if I should wait to source an entire T100 (or at least a front clip) or should I source the parts individually.

Depending on how much I can find a T100 for, I am thinking it will be cheaper and easier in the long run to source the full truck and then swap the parts. This way I will have all of the other parts that I may need, all from the same donor.

I'm also working on my graduate degree so time will also be a factor.

yodathespian87 · 08-05-2009, 12:31 PM

To save you time and money go with the entire truck if you can. Cause you need sensors and connectors under the dash, everything off of the firewalls. Makes it a lot easier. Then the differences between years from 3.4s. It's just a better idea to go with as much as you can. My opinion. Are you stuck on a T-100 3.4? Cause you can get them from Tacomas and 4Runners from years 95.5- 2004.

Dirtoy4x4 · 08-05-2009, 01:57 PM

I was hoping to stick with the T100 only because it will control the A340H or I may swap in the T100 transmission. I'm leaning more towards keeping the A340H however, this way I don't have to worry about crossmembers, transfercase adapters, driveline lengths, or interior modifications.

Basically I'm trying to do this as cleanly as possible. I'm sure I could use a mix of parts from the tacoma's and Runners as well. Mostly I will need a T100 Auto Ecu and engine harness.

yodathespian87 · 08-06-2009, 05:27 AM

If you are going to mix and match parts be sure to get the engine and harness and computer all from the same donor vehicle. Everything you can mix and match basically.

08-03-2009, 08:02 AM	#2 (permalink)
dntsdad Registered User Join Date: Jan 2009 Location: Fresno, Ca. Posts: 292	not sure on some of your other questions but I did see a few pair of Downeys on the Pirate4x4 classifieds if its not too late. Good luck and make a thread noting your work/problems.successes/ideas basically everything for those of us going to take this on in the future. Best of luck __________________ 1992 Toyota Pickup Ex-Cab 3.0 V6 4" Pro-Comp lift

08-03-2009, 10:50 AM	#3 (permalink)
yodathespian87 Contributing Member Join Date: Apr 2008 Location: Colorado Springs, Colorado Posts: 468	Other things to be aware of... Oil Pressure sender swap oil pickup tube and pan swap. engine mount brackets wiring battery tray moved to drivers side thats about it. Good Luck and keep us posted __________________ 86 Pickup 4x2, Manual (Sold) 87 Extra Cab Pickup 4x4, Manual (Sold) 93 4Runner 4x4, Manual, 3.4 Swap In progress 90 4Runner 4x4, Manual, Blown 3.0 (Stripping out for parts then to become a trail rig/camping/fun truck) 94 Lexus SC400, 1UZ, magnaflow exhaust, after market headlights, bought for parts for the swap into the 90 4Runner

08-05-2009, 12:31 PM	#5 (permalink)
yodathespian87 Contributing Member Join Date: Apr 2008 Location: Colorado Springs, Colorado Posts: 468	To save you time and money go with the entire truck if you can. Cause you need sensors and connectors under the dash, everything off of the firewalls. Makes it a lot easier. Then the differences between years from 3.4s. It's just a better idea to go with as much as you can. My opinion. Are you stuck on a T-100 3.4? Cause you can get them from Tacomas and 4Runners from years 95.5- 2004. __________________ 86 Pickup 4x2, Manual (Sold) 87 Extra Cab Pickup 4x4, Manual (Sold) 93 4Runner 4x4, Manual, 3.4 Swap In progress 90 4Runner 4x4, Manual, Blown 3.0 (Stripping out for parts then to become a trail rig/camping/fun truck) 94 Lexus SC400, 1UZ, magnaflow exhaust, after market headlights, bought for parts for the swap into the 90 4Runner

08-06-2009, 05:27 AM	#7 (permalink)
yodathespian87 Contributing Member Join Date: Apr 2008 Location: Colorado Springs, Colorado Posts: 468	If you are going to mix and match parts be sure to get the engine and harness and computer all from the same donor vehicle. Everything you can mix and match basically. __________________ 86 Pickup 4x2, Manual (Sold) 87 Extra Cab Pickup 4x4, Manual (Sold) 93 4Runner 4x4, Manual, 3.4 Swap In progress 90 4Runner 4x4, Manual, Blown 3.0 (Stripping out for parts then to become a trail rig/camping/fun truck) 94 Lexus SC400, 1UZ, magnaflow exhaust, after market headlights, bought for parts for the swap into the 90 4Runner

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08-05-2009, 12:25 PM	#4 (permalink)
Dirtoy4x4 Registered User Join Date: Dec 2004 Location: Vancouver WA Posts: 56	Thanks for the help guys. I have a bit of a dilemma. I'm trying to decide if I should wait to source an entire T100 (or at least a front clip) or should I source the parts individually. Depending on how much I can find a T100 for, I am thinking it will be cheaper and easier in the long run to source the full truck and then swap the parts. This way I will have all of the other parts that I may need, all from the same donor. I'm also working on my graduate degree so time will also be a factor.

08-05-2009, 01:57 PM	#6 (permalink)
Dirtoy4x4 Registered User Join Date: Dec 2004 Location: Vancouver WA Posts: 56	I was hoping to stick with the T100 only because it will control the A340H or I may swap in the T100 transmission. I'm leaning more towards keeping the A340H however, this way I don't have to worry about crossmembers, transfercase adapters, driveline lengths, or interior modifications. Basically I'm trying to do this as cleanly as possible. I'm sure I could use a mix of parts from the tacoma's and Runners as well. Mostly I will need a T100 Auto Ecu and engine harness.