Possible transmission upgrade

[2big4arunner]

So I am starting to plan to do a transmission upgrade to my 2003 4runner v6 sr5. It comes stock with the 4 speed and I would like to swap in the 2005-2009 v6 5 speed version. I am hoping to lower my high speed rpm as well as get more lockup in lower gears. I dont see anything locked up below 50 mph and only lock in 4th gear on my transmission. I have heard that the 5 speed locks in 3rd,4th and 5th gears. This should increase the efficiency greatly considering losses through the system.

What I need to find out and I am going to be searching as well but thought I would ask.

1. Other then the transmission itself, did the transfercase and axles change for the new transmission

2. Does the a750f use a shift computer

3. What gears to put in the truck after the transmission is in IF the rpms haven't dropped the way I hoped at high speeds. (want 1st, 2nd and 3rd to be only slightly lower gearing then original and 4th and 5th to be slightly higher for better highway manners)

It really is too bad that they dont make a 6 speed that mated up to the 1gr-fe motor. It also makes me wonder if I should consider upgrading to the 2006 vvt-i v8 as well. I do want the 2wd mode on my transfer case though. I love being able to take it out and get slightly better mileage.

 

[stevec5000]

Hoping to lower high speed rpm? You're kidding, right? Mine is only running 2000 rpm at 65 so I don't see any problem or any reason to want to "upgrade". I doubt it's possible anyway.

 

[2big4arunner]

What do you have as a transmission?

 

[TRDCal]

To be honest, this project isn't worth it. At best you'll see a couple mpg increase (if that) so the savings in fuel aren't really enough to justify the money your going to spend doing the swap. If it was a simple tranny swap then maybe but these trannys are electronically controlled so your looking a quite a headache.

If your really set on low highway rpm then change the gearing in your diffs. OR if your really set on a 5 speed transmission then sell your 4runner and buy a newer one.

It really is too bad that they dont make a 6 speed that mated up to the 1gr-fe motor.

Trust me, you wouldn't want a 6 speed in the V6 or the V8 for that matter, it would do more hunting than Elmer Fudd

 

[03_4x4Runner]

I think the overdrive ratio is really close on the 4 and 5 speed trans so there would be no gain in highway rpm. The other gears are spaced closer together on the 5 speed and 1st gear may be a little lower. It would require all new electrical harnnesses and computors from a 5 speed vehicle to work. I have a 6 speed auto in my 2011 Avalon and it is awsome. It does not gearhunt anymore than anyother vehicle and really runs great. There is minimal rpm drop on gear changes and give you a lot more choices in manual mode in mountainous terrain.

 

[MikeInNH]

If you want to do this as a fun project then by all means go ahead...

But don't fool yourself that by going this you'll save any money. It would be cheaper to sell your current vehicle and buy a newer one.

 

[ebg18t]

Not sure you will gain much with the 5-speed other than a lighter wallet.

4-speed ratio:
2.847
1.552
1.000
0.700

5-speed ratio:
3.943
2.197
1.413
0.975
0.703

 

[Gecko123]

Compare Side-by-Side


Check out this link. They are all about the same mpg. 2009 a bit better probably due to other technology and not the tranny

 

[BlackWorksInc]

Problem is that you're going to need new PCM, TCM, and possibly a BCM at miminum. Then you're going to either have to swap out large sections of harness and/or cut & splice a harness into the existing vehicle. Possibly relocate existing transmission mounts (I don't remember if they mount up exactly.) You might also need a new driveshaft (Don't remember if the 4 speed is any longer or shorter than the newer 5 speed.)

Theoretically I believe a lot of the bolts and mounting is similar between the transmissions, but I haven't bothered to look at them side by side that closely.

Also are the 4spd transmission shifters different than the 5spd? I haven't seen a 4spd V6 4Runner in our shop in a long long time.

 

[TRDCal]

Problem is that you're going to need new PCM, TCM, and possibly a BCM at miminum.

I heard you might even need to replace the GCM and the VCM but I can't be sure.

 

[NJshadow93]

You may also have to replace the ABC and DOG but don't just take my word for it

 

[M1911]

The cheapest and easiest way to swap the transmission is to swap the entire truck. Go trade for a newer 4Runner.

 

[BlackWorksInc]

Alright you smartbutts!

You know what I mean!