1uz into 1990 lj78 prado

Postoy

New Member
So I have just pulled the tired ole 2lte out of my Lj and have compared the 2 transmissions (Auto). I want to run the 1uz trans as I would like to retain the factory harness and ECU. I've been told I can cut the rear output shaft down to accommodate the Prado Tcase but noticed that the output shaft is ever so slightly smaller in diameter. Has this ever caused issues like stripping? Also what have people done for the tcase shifter pivot? This pivot point comes off the side of the prado trans. Also noticed the shift shaft is on opposite sides, I assume I just need to modify the stock linkage to work?

Thank you! -Matt
 

gloverman

Well-Known Member
Many people think the Prado A343 is the same as the Surf A343 but they are quite different. The Surf auto the transfer slips off and is coupled with a adaptor sleeve. These the output of the lexus A341 or 342 is cut and can be easily swapped to 4x4. I use an additional adaptor to ensure oil feed to rear bearing and that the factory sleeve doesn't split with more than double the torque is put through it.

For the Prado auto I strip the box and put the A341 internals into the A343 housing with a little machining on the rear end. It's quite straight forward if you are confident with auto gearboxes.
 

Postoy

New Member
I've decided to go another route. I am going to use the Prado trans with the 1uz bellhousing and run the entire thing with a spitronic ecu & tcu

I quickly measured and it would seem the front output shafts on both trans are the same.
 

gloverman

Well-Known Member
Ive done a few like that but swap the A341 pump into the box. The clutches are a bit light so every now and again they fail. I have one setup like that in my shop atm but it's running a link ecu and a stock prado Ect with the load signal from the link so I have some tunability on the trans.
 

Postoy

New Member
You mind if I bend your ear a bit? There isn't really anyone in my area that has done this swap to this truck (other than one other) so I don't have many people to ask questions.

Does the pump swap prevent the clutches from failing?

I would assume the spitronic would give me loads of options for tuning the trans too would it not?

Thank you!
 

gloverman

Well-Known Member
Spitronic's will make the trans tunable but basically to start with is to make it run like factory then tweek it from there. There are several different options with trans but the one's I've done the there was (from Memory) about 5mm difference in length to where the splines line up into the converters and it all bolts together and I wanted more spline penetration. The pump, input shaft and front clutch pack swap over nicely.
 

Postoy

New Member
I have decided to go the route of running the stock A341E trans with my 1UZ.

To properly mate the A341E to the Prado T-Case the rear output shaft had to be swapped. Since the Prado only has a 2 prong pick up for the speed sensor that had to be removed from the prado output shaft and the 4 prong from the 1UZ had to be modified and fitted in its place.

The shifter shaft on the 1uz comes out on the opposite side from prado so that was swapped to the other side to match.

Here is the 2 output shafts side by side. Top - Prado (with the 4 prong pickup already installed) / Bottom - 1UZ



Prado case and output shaft with the 2 prong pick up



Left is the 1UZ trans fitted with the prado rear shaft and the shifter shaft swapped
Right the the sad remains of a prado trans



One of the major differences between the Prado trans and the 1uz trans is the rear section of the trans.

This is the prado trans...



You can see the channels are open on the left and right compared to the 1uz trans seen here...



Since the mounting surface of the 1uz trans tail section is quite a bit smaller the side sections have been open to the elements their whole life and need to be cleaned thoroughly before assembly (which I have already done in this picture)

I guess if one got really adventurous you could take the entire trans apart and mill out these sections to match the prado trans but theory has it that there is enough pressure pushing fluid back and forth it shouldn't be a problem. As a side note, I did not opt to drill and tap out the bottom bolt like I've seen on other swaps. I think with the right sealer there should be enough bolts holding everything together.

Another hurdle to over come when converting the 1uz trans to 4wd is the 4wd shifter pivot point.

Prado shifter pivot mount


The 1uz trans lacking of a shifter pivot point


So after a few measurements I came up with a fairly easy solution for this pivot point.



After sorting out the shifter pivot point it was finally time to assemble this whole thing once and for all (knock on wood)

 

Abdur Rehman

New Member
I have decided to go the route of running the stock A341E trans with my 1UZ.

To properly mate the A341E to the Prado T-Case the rear output shaft had to be swapped. Since the Prado only has a 2 prong pick up for the speed sensor that had to be removed from the prado output shaft and the 4 prong from the 1UZ had to be modified and fitted in its place.

The shifter shaft on the 1uz comes out on the opposite side from prado so that was swapped to the other side to match.

Here is the 2 output shafts side by side. Top - Prado (with the 4 prong pickup already installed) / Bottom - 1UZ



Prado case and output shaft with the 2 prong pick up



Left is the 1UZ trans fitted with the prado rear shaft and the shifter shaft swapped
Right the the sad remains of a prado trans



One of the major differences between the Prado trans and the 1uz trans is the rear section of the trans.

This is the prado trans...



You can see the channels are open on the left and right compared to the 1uz trans seen here...



Since the mounting surface of the 1uz trans tail section is quite a bit smaller the side sections have been open to the elements their whole life and need to be cleaned thoroughly before assembly (which I have already done in this picture)

I guess if one got really adventurous you could take the entire trans apart and mill out these sections to match the prado trans but theory has it that there is enough pressure pushing fluid back and forth it shouldn't be a problem. As a side note, I did not opt to drill and tap out the bottom bolt like I've seen on other swaps. I think with the right sealer there should be enough bolts holding everything together.

Another hurdle to over come when converting the 1uz trans to 4wd is the 4wd shifter pivot point.

Prado shifter pivot mount


The 1uz trans lacking of a shifter pivot point


So after a few measurements I came up with a fairly easy solution for this pivot point.



After sorting out the shifter pivot point it was finally time to assemble this whole thing once and for all (knock on wood)

Hi Postpoy,

How is your project coming along? Have you finished the built and is it reliable? I'm going to work on this so any more information would be highly appreciated. I will go with Y60 Patrol axle. Will share more information as I move along.
 
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