Engine Swap - 1998 3.4l into 1997 with 3.4l

[danthemanx07]

I am a sucker for a 3rd gen. I just sold one and am now looking at another. It is a 1997 with 340k miles - but it is a 5 speed.

I am not terribly concerned about the miles (if I can get it for the right price) in part because I have a 1998 3.4l with 150k ish miles on it in my garage.

I assume that the 1998 would swap right into the 1997, but I wanted to check the hive mind before making a you-know-what of my self. The 1998 came from a 4runner equipped with an auto, but I really don't see why that would matter unless y'all have something different to say.

I searched through various threads on this, but many of the comments seem to be made under the same assumption that I have - that it should work. I did find at least one thread though where a fella got a 1998 engine into his 1997 but was unable to get it started. The thread died without a resolution.

 

[phattyduck]

That should swap with no issue. There are very minor wiring differences through the years, but the long block is the same, mechanically. (they updated the head gaskets through the years, but that isn't a compatibility issue)

You already have to swap harnesses (manual vs. auto), so most of the differences will already be taken care of.

-Charlie

 

[danthemanx07]

That should swap with no issue. There are very minor wiring differences through the years, but the long block is the same, mechanically. (they updated the head gaskets through the years, but that isn't a compatibility issue)

You already have to swap harnesses (manual vs. auto), so most of the differences will already be taken care of.

-Charlie

Thanks for the input. Curious what harness I would have to swap though. The engine has its harness, that runs through the big black boot on the passenger side of the engine bay to the ECU. My assumption would be if anything would need swapped it would be all of the plugs from this harness to their respective connections on the engine going in.

The transmission harness runs up to the ECU and terminates there.

I wouldn't be swapping the transmission. Am I missing some connection between the engine and transmission that I am not aware of?

 

[phattyduck]

Am I missing some connection between the engine and transmission that I am not aware of?

The engine and transmission use the same harness. It runs from the boot on the firewall you see, over the engine to the driver's side, then down and back to the transmission, over the top to the transfer case and rear O2 sensor. To remove the engine and engine harness, you have to unplug everything on the transmission and it will come out with the engine. You also are supposed to remove the harness from inside the cab (ECU plugs and a few plugs to the dash harness) to have that side come out with the engine.

On a MT truck, it will only have the reverse light switch, transfer case switches and rear O2 sensor wires. The AT also need a few speed sensor signals, the neutral safety / range switch and the solenoid wires.

-Charlie

 

[danthemanx07]

The engine and transmission use the same harness. It runs from the boot on the firewall you see, over the engine to the driver's side, then down and back to the transmission, over the top to the transfer case and rear O2 sensor. To remove the engine and engine harness, you have to unplug everything on the transmission and it will come out with the engine. You also are supposed to remove the harness from inside the cab (ECU plugs and a few plugs to the dash harness) to have that side come out with the engine.

On a MT truck, it will only have the reverse light switch, transfer case switches and rear O2 sensor wires. The AT also need a few speed sensor signals, the neutral safety / range switch and the solenoid wires.

-Charlie

Got it now. Thanks for the break down!

 

[AFT3R5H0CK]

I'm in the process of doing the same thing. Which power steering pump did you use? Mine are different.

 

[phattyduck]

I'm in the process of doing the same thing. Which power steering pump did you use? Mine are different.

The only (important) difference should be the idle-up mechanism. One will have an electrical switch+plug and one will have a pressure operated valve. Use whichever matches your ECU and wiring.

-Charlie

 

[thegipper]

The only (important) difference should be the idle-up mechanism. One will have an electrical switch+plug and one will have a pressure operated valve. Use whichever matches your ECU and wiring.

-Charlie

I swapped a 99 engine into a 97 truck. All I had to do was swap the wiring harness and everything (minus the PS idle up thing charlie is talking about) plugged right in.

If I remember correctly, I just swapped over the PS pump from the 99 truck.

The hardest part of the entire swap was getting the motor mount bolts back in.

Good luck!

 

[walkercars2]

Doesn’t sound like a big deal to me! Stick with your gut on that one