Honda Prelude Forum

Originally Posted by SlickLudeR

re-post from preludeonline

Originally Posted by SlickLudeR

Originally Posted by SlickLudeR

i figured id post this here 2



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







by the way i was thinking if u can just upgrade the internals of the atts unit is there any way of not allowing the ecu to disable the atts system so its on no matter what ?



Well moving on tonight on the ATTS unit, i took a look and the left side cover and removed it. The black hoses you see here are the oil cooler hoses that run on top of the transmission and connect to the bottom of the radiator.



Here you can see the locations of the oil orifice and the oil filter for the ATTS unit. Notice how both contained a spring, the spring in the orifice more than likely controled oil pressure throught the ATTS unit.








After separating the left cover you can see the left clutch assembly and the oil pump.

Originally Posted by LudiousMaximus

I recently bought a 1999 Prelude SH, and I am doing some maintenance on it. I will be replacing all of the fluids, including the fluid in the ATTS. I have a question though. How do I know that my ATTS unit is working the way it is supposed to? I read on Alldata that the ATTS unit uses clutches to transfer power in a turn, but are these clutches serviceable? I've tried searching around, but I couldn't really find an answer to my question. Sorry if this topic has been covered before. Thanks!

Originally Posted by LudiousMaximus

Thanks a lot for that information. I tried searching, but I guess I'm not very good at it.

Originally Posted by johnboyjdm

im sorry sir iv look'd at it and iv look'd at it some more but and let me say sorry agian ...it just dusint look rite .its a prelude the best look'n honda ever built respect it .

Originally Posted by AoK303

I love my Atts still not 100 percent at using it but i hit turns with awd vehicals and show them up since it works off of the Tourqe pressure it never turns on at the same time or i could be wrong i searched too, to see if someone had written a post about using your atts to the max

Originally Posted by BB2H22A4

You want to get some pizza and f*ck?

WHAT, YOU DON'T LIKE F*CKING PIZZA!?

Originally Posted by Si Speed

That's ****in' success baby!

Originally Posted by orbslude

even though our cars have atts does not mean it handles better than an awd drive car such as an audi quattro, evo or sti

Originally Posted by firebos7

I actually had an wrx driver comment on our handling before...

was getting it etested and he goes, man that a prelude? nice. My friend has one of those... sticks to the road like a damn spider (he meant the... insect) wish my car handled that well

... I was like... .......

Originally Posted by BB2H22A4

You want to get some pizza and f*ck?

WHAT, YOU DON'T LIKE F*CKING PIZZA!?

Originally Posted by Si Speed

That's ****in' success baby!