Also, to anybody who wants to do this... you just can't go and put a "lockup" converter in a standard auto trans. You have to get a KM-148L unit or the magical 372L unit!

I swapped in a V6 lockup auto from a 1991 4 door Montero behind my 4D55T in my 1988 Montero. It went right in and took maybe 5 hours to swap.

I liked the non lockup better in town because it spooled up quicker but the lockup was better on the highway. Anyway after that experience i've decided that when it comes time to auto swap my Mighty Max i won't pass on a non lockup, i'll just take whatever i find first.

Thanks for the replies guys. I appreciate it. monte, what an epic battle with the tranny brother. Talk about perseverance, way to go!

From my preliminary research I've come to the conclusion that I need very little work to perform the Lockup T.C. upgrade. I'm in a bit of a different situation from monte and KevinC. Where they did this swap for a 4 cylinder turbo setup, I'm doing it for my 1989 6 cylinder AutoTransmission. I won't have to go through the trouble of swapping transmissions, I think I'll just need to swap out a few parts. I'll run through it now with you.

• Lockup Torque converter
• Fluid pump body
• Inner pump gear (I believe this is the Drive Gear)
• Outer pump gear (I believe this is the Driven Gear)

This is a screenshot taken of a technical service buliten sent to me from BigBlue. There is a line in there towards the bottom that specifies the non-interchangeable parts between 1989 & 1990 torque converters. This is why I believe I'll only need to swap out a few parts as opposed to a whole transmission.

You need the valve body from the lockup unit. The lockup function has its own, separate circuit. The feed line is not found in the standard valve body. When I first did this swap, I confirmed that the case was the same.

My memory is a bit fuzzy, since its been 10 or so years since I did it. The special valve body times the lockup to come in after OD is engaged. Its an extra circuit and the standard body I looked at did not have it.

Also, the factory manual from that era show the circuit, but it was not in the actual non lockup units. Basically, the manual is wrong.

10 + years is a long time. but that's what I remember.

Thanks for the Feedback KevinC, I'll have to go do more research on this and document what I find. I'll keep you guys posted.

I had some time to think about my swap.

1: I compared the auto tranny from a 1987 4 cyl to the same basic model but from a 1990.

1: The valve bodies were definitely different. My 1987 valve body did not have the extra valves to control the lockup converter.

2: The cases were identical.

Looking at this as critical thinking exercise, all I proved was that my 1987 4 cyl auto does not have the correct valve body for the swap.

So the question is, did they put the valve body for a lockup transmission into non lockup transmissions?

It's possible and reasonable that the extra valve does nothing and hurts nothing so it could be in there.

Most manufacturers roll a change in all at once. So it seems unlikely they would just put a new valve body in and not the other lockup parts (including the different ratio gear set). You never know, you might get lucky.

How can you tell? The lockup valve body uses a different filter. If you go to sites like Rockauto, you should see two choices for filter screen in 1989, one for the lockup unit and the other for the standard unit. Still... Kind of confusing.



The above guide should help. The filter on the bottom left is whats used on the A44DL AKA the lockup unit. If you don't have that filter on your valve body, you don't have the right one for your lockup converter.

Front page of catalog.

Valve body diagram: Lockup unit




Valve Body Diagram - Non Lockup

Upper left corner you can see two valves on the lockup valves body that are "new"



Lockup Valve Body from my swap with the valves labeled. One thing to note, the lockup of the converter happens after the unit goes into OD, it's a staged event. It takes a couple of seconds to happen and is the reason why the lockup unit has the extra valves.

I had the stator modified on my converter to allow a bit higher stall. Quick spool around town and lockup on the highway.