Revi

Well, a while back i purchased and installed a Type-S motor in my 98 SH. Ever since the first test drive after i installed the engine i always had an ATTS light. After several troubleshooting experiences i decided i would swap out the ATTS unit that came with the Type-S motor and put in my old known good ATTS unit which i never had a problem with.
This past week i removed the engine to install a new clutch and rear main seal, so i took the opportunity and swaped ATTS units. I was happy to discover my ATTS light was now gone. This answered my question about needing the JDM ATTS ECU when running the Type-S motor. I always believed the JDM ECU was having conflics with the US ATTS ECU which would cause the ATTS light to come on, but after swapping ATTS units, the ECUs seem to have no problem with one another.

Well now that i have a bad ATTS unit sitting in my garage i was thinking of what to do with it. I was not going to sell it to anyone under its current condition, so i decided to do the next best thing... TAKE THAT BIATCH APART!

For those who have never seen or know what the ATTS unit is or does, here it is below. The ATTS unit comes in all Type-SH Preludes, as well as the JDM Type-S engine (NOT THE EURO-R). It takes the place of the intermediate shaft and works as a torque transfer system which transfers torque to either the left or right wheel while under heavy cornering.

Here ive pointed out some of the main sensors/parts of the ATTS. The breather tube pointed at below travels up around the intake manifold, and it is curved into a "U" and left open. It sits right by the Fuel Pressure Regulator.

Here is the right side of the ATTS Unit. The extension tube you see is the section that goes inside the transmission.

And here is the left side of the ATTS, this is where the drivers side driveshaft connects. Notice the ATTS fluid fill bolt.

After removing the right side cover, i was amazed at what i saw next:

This is believed to be the heart of the ATTS unit and what allows it to be able to transfer torque to the needed wheel under heavy cornering. This sucker came out as a whole, and i was amazed to see that it consisted of 16 different gears!!! When you rotate the inner gear assembly the outter gears would rotate the opposite direction. It almost looks like a miniature LSD.



Notice the ball bearing assembly.

Here you can see the two gears that sit inside this gear case. The #1 and #3 gears sit inside the case with the washer (#2) in between them. Part #4 sits inside gear #3.

This is what it looks like with the extension tube attached:

After removing the "gear case" you can see the ATTS unit clutch assembly:


Over all there are 3 clutches in total, along with 4 friction plates.

Until this point this is the only sign of wear i have found.

All the clutch dics looked like they were still in good conditon, however. After removing all the clutch and friction discs and a snap ring, a large spring came flying out at me. Luckly it hit my arm and not my face.. This appeared to be used to keep or put pressure on the clutch discs.


This might be a pointless thread, but im finding it interesting to actually see and learn about all the parts the ATTS unit has. Im anxious to take it all apart so i can see how it all works. I will continue to take the rest of it apart tommorow and take a look and the oil pump inside the unit and hopefully find out why the ATTS unit was throwing codes. Stay tuned


Modified by Revi at 5:21 PM 2/9/2007


Modified by Revi at 5:22 PM 2/9/2007

piotrush

wow - great post. Ive always wondered what that sucker looked like inside. Time to archive this thread.

117

The Helms manual (at least the 97-98 version I have) explains exactly how ATTS works. I wouldn't expect too much wear on the clutches, they don't normally slip since the unit is on or off.

Revi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 117 &raquo;</TD></TR><TR><TD CLASS="quote">The Helms manual (at least the 97-98 version I have) explains exactly how ATTS works. I wouldn't expect too much wear on the clutches, they don't normally slip since the unit is on or off.</TD></TR></TABLE>

This is true, but reading about it and actually seeing the parts in motion and in your hands is different. I guess it comes from my younger days when i used to take apart my remote control cars and other toys just to see how they worked.

117

No doubt, it is very interesting to see the actual parts! Hopefully everyone can see why an LSD won't work well with the ATTS unit. Also, the coaxial input on the driver's side is quite interesting.


Modified by 117 at 8:17 PM 1/8/2007

arthentic

hey revi. i had just joined this forum to look for someone who might be alble to help me with my prelude problem. since i just joined, i have a limited number of posts. i was wondering if you could give me your AIM screen name if you have one so that we could talk. mine is angrytheworm. thanks.

Revi

Sorry man, i dont have AIM but you could alwasy post the question. There are alot or people in this forum that can help you out. Some know alot more than i do. But if you want you can send me an IM or email me at Lude98SH@yahoo.com and i will try to help you out.

N.A.N00B

Here's a little history on the atts developement and the guy that came up with it.

http://dwolsten.tripod.com/articles/mar97.html

btw, great pics! always wondered what exactly was inside

arkosh.kovash

pointless?... ppsshhhh! very useful information. planned on doing this to my extra ATTS unit. i have never seen this type of information on HT, great post.

vinuneuro

Great thread. Getting custom clutces made for the unit might be something interesting to increase the power ATTS can handle.

Revi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by arkosh.kovash &raquo;</TD></TR><TR><TD CLASS="quote">pointless?... ppsshhhh! very useful information. planned on doing this to my extra ATTS unit. i have never seen this type of information on HT, great post.</TD></TR></TABLE>

Thanks, man i appreciate it. Just trying to add alittle more tech to this forum. We'll see how the other half of this thing looks in the next few days.

VTECnKEN

Indeed, a redeeming thread amongst the usual h-T crap.

Nice pics and description!

Btw, the round gearset you're holding is a planetary gearset similar to the types you find in Non-Honda automatic transmissions.

arkosh.kovash

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">Great thread. Getting custom clutces made for the unit might be something interesting to increase the power ATTS can handle.</TD></TR></TABLE>

:drool: i like this thought process.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Revi &raquo;</TD></TR><TR><TD CLASS="quote">We'll see how the other half of this thing looks in the next few days.</TD></TR></TABLE>

goodluck

Revi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">Great thread. Getting custom clutces made for the unit might be something interesting to increase the power ATTS can handle.</TD></TR></TABLE>

yeah the clutches them selfs seem pretty simple, they almost seem like smaller versions of regular clutch discs. The problem would be finding someone to make some, and the cost.

honda_andy

i wonder how similar this atts unit is to the one on the new RDX's and RL's, i know they are 4wd but they seem to be able to handle a lot more power and torque.

AzCivic1.6

why did they use this overly complicated thing when they could've used a torque biasing diff like the quaife?

TheWalrus

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AzCivic1.6 &raquo;</TD></TR><TR><TD CLASS="quote">why did they use this overly complicated thing when they could've used a torque biasing diff like the quaife?</TD></TR></TABLE>

i always wondered this too...esp since a regular lsd takes up no extra space, isnt computer controlled and weighs less...ludehawk (anyone remember him? he went to the track a lot) once posted that atts is better for long hi speed sweepers while a clutch type lsd is better for slower sharper corners like AutoXing.

very nice post revi thanx for informing us all...good work

VTECnKEN

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by honda_andy &raquo;</TD></TR><TR><TD CLASS="quote">i wonder how similar this atts unit is to the one on the new RDX's and RL's, i know they are 4wd but they seem to be able to handle a lot more power and torque.</TD></TR></TABLE>

The SH-AWD in the RL uses electromagnetic clutches and even though it can bias power distribution by 100% to either rear wheel, it's not receiving 100% of the engine's 290hp output.

flyrod

Thanks for sharing your pictures! Any idea how the clutch is engaged/disengaged? Are there solenoids that push on it or does it use oil pressure somehow? It looks like that spring keeps the clutch disengaged, creating an open differential, then there must be some mechanism to compress the clutch pack. Anyway, looks like an interesting device.

KEVLARsh

Nice Thread, pics are great

Revi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by flyrod &raquo;</TD></TR><TR><TD CLASS="quote">Thanks for sharing your pictures! Any idea how the clutch is engaged/disengaged? Are there solenoids that push on it or does it use oil pressure somehow? It looks like that spring keeps the clutch disengaged, creating an open differential, then there must be some mechanism to compress the clutch pack. Anyway, looks like an interesting device.</TD></TR></TABLE>

There are acturally 3 solenoids that are attached to the ATTS unit, but they are on the left side of the piece, which i will be looking at tonight. Im interested in seeing if its possible to be able to rig the ATTS unit to be in a locked state at all times.

CAN97SH

Very cool. I've always wondered what the clutch looked like in there. I know LSD's work great with straight lines. What are some of your opinions of the ATTS compared to an LSD in the corners.

Chuckles99SH

Locking atts would be awesome, but I would be interested to see if the clutch pieces could be beefed up to allow ATTS users to go FI.

Revi

Well the clutch discs could def be made stronger, but its the pressure put on them that will determine their grip strength. So depending on wether its the spring or the solenoids that put pressure on the discs is wether or not the ATTS unit could be beefed up. But if the spring is what puts on the pressure, much like a pressure plate would on a regular clutch, then it would be easy to manufacture a stiffer spring thus adding more pressure.

117

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Revi &raquo;</TD></TR><TR><TD CLASS="quote">There are acturally 3 solenoids that are attached to the ATTS unit, but they are on the left side of the piece, which i will be looking at tonight. Im interested in seeing if its possible to be able to rig the ATTS unit to be in a locked state at all times.</TD></TR></TABLE>

It's my understanding that the ATTS unit only turns drives the driver's side wheel 15% faster or 15% slower (depending on which direction the car is turning). It does not lock the two driveshafts together, so I am not sure exactly how you'd go about doing what your describing.