Another auto trans upgrade

[gofastgeorge]

For those of you who don't think that the only way to go fast with a 7M is with a 5-speed,
and have done the accumulator shim thing for much better shifts,
there is another upgrade that can be done for better performance.

I have found out that the overdrive gear cluster from an IS300 Lexus has a better ratio.
It is a .75:1 overdrive, where the Supra is .702:1.
Allows less rpm drop when shifting from 3rd to 4th, and better accelleration after that.

Also, the IS300 trans has a 25% larger pump for better oil supply, and cooling.
And the IS300 pan is larger for more fluid capacity.

Not all is bolt in though.............

There is a sheet metal disk spot welded on the IS300 overdrive drum,
that is used for a speed sensor on the IS, that needs to be taken off.
Pretty simple, I just drilled into the 3 spot welds, and it popped right off.

Not so simple, the spline that goes into the torque converter is a 20 count spline, not the 28 count that the A340E uses.
Not a major peoblem, since any converter shop worth a damn can change the spline in the converter.
I am having these people build me a 9" high stall converter for that spline.
http://www.greatconverters.com/
They have already built a 9" for the standard A340E for me, and were the only people I have found who could do so.
And believe me, I have tried a lot of converter people over the years, and None of them could do a 9", besides that $1600 Level-10 thing.

 

[dusthead]

ok...f'ing awesome. +1 for automatics. (and i just clicked that link) holy crap...you know the guy that i talked to a few months back about upgrading my torque converter....he said like $300 to up it to a high stall...though he didn't give me numbers in RPMs...i was still learning about them anyways. right now i forget who i talked to about upping mine to a high stall - but they basically said that if there's a guy that can do it - sarge can.

soooo....keep this updated with pics and info on the work you're doing?? i'm crazy interested...i have 1 auto installed, 1 on my garage floor, and 1 in my parts car that supposedly has it's valve body modified to shift like a 5spd. reason i say supposedly is because there's no real proof of this...just what the previous owner said.

so if you need an extra...lol. let me know. oh, and from what i read - the pump and pan are bolt-on?

 

[gofastgeorge]

For refference, the number on the IS300 trans that these parts came from was 35-50LS .

 

[mdr40z]

nice investigative reporting, looks beefy and worth a try

 

[gofastgeorge]

And it is easy to put in.........
Just unbolt the pump, and the OD gear set is the first one you find.
It just slides out into your hands.
Slide the new one in, stick the new pump in, & put the bolts back in.
(use a new O-ring on the pump, and new seal, just to be safe from leaks.

 

[TurboStreetCar]

The pump is bolt in minus the difference in converter splines?

 

[gofastgeorge]

The pump is bolt in minus the difference in converter splines?

Yes sir.

 

[IJ.]

Always liked the OD ratio

Then again my engines have always made stupid Tq and I expect the new one to do the same!

 

[suprahero]

^Braggggggger!!!!!!!!

 

[gofastgeorge]

Always liked the OD ratio

Well, there also is mileage to be figured into the equation.....
If someone is concerned with it on a daily driver (I'm not),
then the lower OD may not be the way to go.

 

[Drake69]

This thread has the potential for some serious win. I would like to see how to squeeze more power from the auto tranny like that. Also would like to see prices posted and some detailed instructions on how it was done or where to go for the specialty stuff.

Great read! +1

 

[gofastgeorge]

I paid $300 to my door for the IS trans, from a guy in Florida.
He had it on eBay, but didn't get any bids.
I had been busy trying to verify fitment, as much as I could.
But that was a rare price for an IS trans, most of them go for over $500.
(not that I actually seen any of them sell for that, but all the used trany jockies on eBay think that is what they are worth)
Still not a bad price, since just the plannet gear cluster is over $1000 new at a dealer.
Not sure on the final price of the converter until the Sarge get's it built.
But I will update the thread when I do get the bill.

Now if you can find a burnt trans, that should be cheaper.
Burnt plates don't matter, since all of the plates are the same in the Supra A340e.
Or one that came out of a wreck, that has case damage.

 

[mdr40z]

so does that mean we could swap in the paddle shift too, like maybe the steering wheel would swap too?

 

[gofastgeorge]

Nope.....
Totally different system.

 

[mdr40z]

so a complete trans swap is not an option, I was thinking maybe the basic box might be the same except for perhaps the bellhousing and tailshaft (TC of course too) or something like that (wishful thinking I know)
I'm getting a little tired of my TH350, time to try something new

 

[TurboStreetCar]

Go AOD. If my tranny doesn't hold up it's where I'm going.

 

[gofastgeorge]

Well, if you could handle the 350 swap,
then going to the IS 5-speed auto might be a possibility.
With maybe a Supra-Stick to handle the electronics (guessing on my part),
and a 7M bellhousing.

 

[mdr40z]

Yeah! I'd sure like the 5-speed auto w/paddles, it's probably just got a trans computer that might swap too.

the 350 swap wasn't that big a deal really but the low gearing is a pain, 0-90 or so is outta this world tho

 

[gofastgeorge]

Most Toyota steering columns have the same spline.
You would need the IS steering wheel, and combo switch to get the multi-contact under the wheel.

I made mine using part of the multi-contact ring from an old Celica that had the cruise control mounted in the steering wheel,
but it was a lot of cutting & epoxy to get it mounted,
and a Momo wheel adaptor for use with multipal wire paths.

 

[dusthead]

Go AOD. If my tranny doesn't hold up it's where I'm going.

....AOD? Define please.