GS450H Discussion

[celeron55]

A quick question:

Is the IS300H transmission suitable for use without an external motor on the input shaft like the GS450H is?

I see it doesn't have the electric oil pump like the 450H transmission does. Does this mean it's basically like a 450H transmission without the electric oil pump (needing input shaft rotation) or does it have a different way of creating oil pressure?

[Jack Bauer]

I don't know for sure but my sense from looking at it would be they deleted the external oil pump and limited the already limited ability to drive with the engine off. You might be able to fit an external electric oil pump to the cooler lines and lock the input as normal.

[sfk]

The transmission variants used in the IS also didn't have the 2 stage output so that may effect top speed or motor efficiency?

[xp677]

There are plenty of electric oil pumps on the market - you can likely place one in-line with an oil cooler.

I'd open up the transmission and have a look at how the oil passages are arranged first.

Failing all of that, if it has a mechanical pump on the input shaft similar to the 450, you could lock the power split device (weld, or fabricate a replacement) instead of locking the input shaft.

[celeron55]

Anyone currently able to take measurements from a GS450H transmission?

1) How much does the input shaft poke out from the general highest point of the back of the bell housing? (e.g. set a 20cm ruler there and measure from it)

2) How long is the taper at the tip of the shaft before the splines appear fully? (i.e. the length of the tip portion without proper splines)

[RE3Rotor]

1) How much does the input shaft poke out from the general highest point of the back of the bell housing? (e.g. set a 20cm ruler there and measure from it)

29mm

2) How long is the taper at the tip of the shaft before the splines appear fully? (i.e. the length of the tip portion without proper splines)

6mm

[celeron55]

Well, I went crazy and bought one of these things. Boy it's massive, not sure how I'll fit it in the car but I'll try.

I measured this output flange. It has 26 quite rectangular splines. Looks like it's not a common one, offroad and racing shops don't have anything compatible on their shelves so you'll have to adapterize your driveshaft onto this flange. For that there seem to be some off-the-shelf options on the market. They don't seem to be very useful to me though.

The bolt pattern on the flange has 52.5mm radius and the center pilot is 16mm diameter. It does not seem to have a machined flange surface, only the 22.5mm diameter ~3.2mm deep recesses around the bolt holes are machined. Regardless, the flange surface seems to be quite consistent.

Funnily enough the input shaft spline perfectly matches the input yoke spline of my original driveshaft (that I won't be using, and which wouldn't be very helpful obviously unless I wanted to install the transmission backwards. Which would work I guess. Please tell me it wouldn't.)

[Alexstarex]

may be you use part of the universal joint from 450?

[sfk]

Funnily enough the input shaft spline perfectly matches the input yoke spline of my original driveshaft (that I won't be using, and which wouldn't be very helpful obviously unless I wanted to install the transmission backwards. Which would work I guess. Please tell me it wouldn't.)

If you weld up the planetary gears the input shaft will spin the same speed as the output shaft (in one of the 2 final drive ratios at least. Not sure which one is 1:1, high or low)

So yes, you could mount it backwards and use the Input shaft on the gearbox as an Output shaft in theory.

[Jack Bauer]

A bmw E65 7 series propshaft is a perfect fit. I just needed to bore out the center rubber spindle thingy by 0.5mm.

[celeron55]

I'm putting this in a vehicle that has a single propshaft with a U joint at each end. You can't really mix and match joints in ways they weren't designed for, so this one calls for adapterizing a U joint on the transmission end.

Propshaft crash course:

The giubo flex joint (originally on the GS450H transmission) is for when the propshaft leaves the transmission at a fixed straight angle. Whatever comes after it doesn't really matter because the giubo absorbs all changes in angular velocity and it also allows for a little lengthwise movement. If the propshaft connects to a solid axle, then you need something to account for the larger length changes that come with suspension movement of a solid axle (and obviously an extra joint with a support bearing). In the GS450H there's a U joint at the middle of the shaft and another giubo at the differential. E65 is similar but I'm not sure what the joint at the differential is, or whether there even is any.

A propshaft with a U joint at both ends (my case) is for when the propshaft leaves the transmission at an angle, and arrives at the differential at the same angle. The angle can be anything and change during driving, but it needs a non-zero angle to lubricate the joints properly and wear the joints evenly, and it needs the same angle at the other end in order to sum up changes in angular velocity during rotation. In other words the ends have to be parallel, but not on the same line. It also needs a lengthwise sliding portion at some point in the shaft as U joints don't have any play in them.

There can also be constant velocity joints in propshafts. One can be used as the middle joint in a two part shaft with U joints at its ends to avoid using an odd number of U joints. Things called double cardans, which I think also is a CV joint, are used in offroad vehicles on either or both ends where the suspension makes the differential move all over the place or where the differential can be made to point at the transmission all the time instead of being parallel to the transmission all the time.

Multi-part truck propshafts sometimes have an odd number of U joints in them with small angles and with no giubos. I guess they work because of the small angles and slow speeds.

[cajunfj40]

Hello celeron55,

Finally something mechanical I've actually messed about with, and can offer a usable suggestion for.

What size U-joints are in your propshaft? Find a mounting flange that adapts to that size u-bolt, with whatever bolt pattern. There are also "adapter" u-joints available between common sizes, at least for US ones. Then make an adapter puck out of aluminum or similar that has the bolt pattern from the Lexus rubber flex joint flange on one side and the bolt pattern of the driveshaft flange on the other. You should be able to find a flange bolt pattern that's compatible enough to not overlap bolts with the Lexus one. If not, either a thicker adapter puck with studs on both sides, or a two-piece job like a wheel pattern adapter. The thickness of the adapter determines how much further forward than stock the mounting face of the Lexus transmission needs to be vs. the old one. This sort of aluminum driveshaft spacer is used a lot on trucks with cheap lift kits, to make the driveshaft that little bit longer to handle the lift. All it requires is having the center of both bolt circles the same, and maybe balance it. Note: you'll need a slip-joint in your driveshaft to handle length changes, if the original vehicle had a slip-yoke on the end of the transmission instead.

Alternately, you can create a mounting flange yourself - or have one made - with the Lexus bolt pattern on one side and the correct "saddles" and strap bolt holes for your U-joint on the other. I hate those u-joint straps, though, flanges are much nicer. Even if they sometimes fall down and whack you on the head because you trusted the small centering lip to hold it up instead of putting a bolt in it while you were test fitting it...

HTH,
-cajunfj40

[buzz86us]

would this motor be viable for a Toyota T00DX?

[RE3Rotor]

Well, I stripped the bottom of the inverter and still couldn't get the bus bars out. How do others bypass the boost converter?

[Jack Bauer]

There's no need to do any of that! Please watch the video I made recently on the gs450h system.

[RE3Rotor]

There's no need to do any of that! Please watch the video I made recently on the gs450h system.

I watched most if not all your videos. I have to admit, most of the time when it gets technical, the information just goes over my head.

One thing I haven't read/saw is if we connect the HV power to the posts on the side of the inverter, do we have to worry about is the boost converter being energized? And if I am planning on running the GS450h AC compressor, how do I go about doing that?

My current plan is to find some Chevy Volt pack (~360V) to drive the inverter and motor.

[arturk]

Here is how I connected it in my test setup.
You need to remove black metal cover on the side to expose plastic vent. Then you have to knock this cover out piece by piece. Start from the center, use some punch or flat screwdriver and small hammer. It is very thin plastic, do not use to much force.

[RE3Rotor]

I have opened that up. I am just wondering if there are any concerns regarding the bus bar that runs up to connect with the boost converter.

[xp677]

Oh wow, you really went there!

To remove those bars, you just need to open the converter lid, remove the external housing for the original toyota connectors, and slide the bars out. They are fastened at both ends, as bus bars normally are.

If you are not using the converter, you can just leave those bars in place. If you plan on using the converter, remove the bars and sort out converter in/out/ground separately. In our application, the inverter and converter are separate units, they do not need to be connected with the bus bars (and if you're trying to use it with my hardware/software, they definitely should not be connected). Power the converter separately.

[jcwright45]

Any ideas on how the centre of this comes out? I recall Damian’s video shows him wielding it to a bit is square tube.

[celeron55]

It comes out by using an angle grinder.

[RE3Rotor]

Any ideas on how the centre of this comes out? I recall Damian’s video shows him wielding it to a bit is square tube.

It may be too late now. But do you happen to have the part number for that piece? My gearbox didn't come with it.

[arturk]

Any ideas on how the centre of this comes out? I recall Damian’s video shows him wielding it to a bit is square tube.

If I understand your question correctly center does not come out. Damien just cut those "wings" and welded center piece into piece of square tube and then to metal plate.
You can do the same but here is what I did. It works well so far but spacers need to be large diameter (~1").

[arturk]

Does anyone know the best procedure to adjust transmission fluid level without connecting complete GS450H into Toyota Diagnostic System? Obviously this is not an option since transmission is in a different car. I do realize it may difficult to get level precisely but at least to get it to lever it is safe to operate it. I think that according factory procedure transmission has to be filled to the level refill plug (top one) and then level has to be further adjusted.
Very little info online. I am sharing what I found. Any suggestions?

[jnsaff]

I don't know about the Lexus ones (yet) but for the Toyota ones Prof Kelly says: fill it until some starts coming out and then you're good. Ideally when the transmission is on a level ground the oil should be not coming out but not below the fill port. Practically I don't think you should worry about milliliters and get it mostly right.