I have an 03 4.7 Tundra 4 speed, 120k miles. I'm thinking about swapping a 5 speed automatic from an 05-06 into my 03.

I've done alot of searching and couldn't find very much information about it.

I do know that the 5 speed has better gear ratios, especially 1st to 2nd, and is more efficient than the 4 speed. Also mine is starting to slip between 1st and 2nd.

I've heard through the grape vine a few people on here have done this swap before. I'm assuming I would need the 5 speed tcu, maybe a new driveshaft, cooler lines, not sure what else?

I'm pretty new to tundras, only installed headers and k&n intake so far but I've done a 5 speed manual swap on my bmw and a few engine swaps.

Any help is much appreciated!

Problem is that TCU and ECU is one module, so it will be impossible for you to do that. Another thing it will bolt on to your engine, but they are completely different, where 03-04 use speed sensor for speedo, and 05+ tundra don't even have that sensor in trans, it uses ABS sensors for speedo, and there are many other little things that may come into issues...

Probably be easier if you can find the engine and tranny from an 05+ Tundra and swap that, and you'll get a more powerful engine out of it.

Thank you for the replies.

Swapping the engine and tranny sounds like the only way to do it since the ECU holds the TCU also. That means I would need the newer ECU, wire harness, gauge cluster (which looks way better anyway), and I would imagine a few other things. I will do some searching.

Here's some info about both transmissions that may help you out.

http://www.tundrasolutions.com/forums/1gen-tundra/203256-1-gen-tundra-transmission-tech-thread/

If you really want the low down on our transmissions, I'd suggest contacting John at IPT transmissions to answer your questions.

I actually started a thread before I scrolled down and saw this one... Oops! Anyway, talking to one of the guys here in my office, he's working on a project for somebody that involves the new generation of Toyota Hilux. There are some big hurdles to overcome, but he's trying to figure out parts of the CAN system. I asked him about transmissions and such. He thinks that by the time he's done, he may be able to put together some programming that will control the transmission for the newer 5sp. We'll just have to wait and see though. It's gonna be a couple of weeks.

My trans isn't slipping yet, so I'm gonna see if I can hold out. If your trans starts having major problems before then, get it rebuilt before you do major hard part damage. IPT transmissions is probably your best bet.