Trans problems... What caused this???? Pics

Posted By: DemonDust

Trans problems... What caused this???? Pics - 09/18/11 11:33 PM

I'd like to know what your guys thought are.....

Everything in the trans looks like new, like when i put it together except the front drum (high/reverse I believe is the other name)

What caused this??? The clutch pack is welded together and the aluminum in the bottom of the drum is melted everywhere. I literally had to pound the front drum off the input shaft.

Here are the rear clutch discs... They are still like new..

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/18/11 11:54 PM

Well either the front clutch was slipping in high or it was dragging in 1st and 2nd. It's pretty hard to say from what is pictured as to what happened though. What exactly was the progression of systems?

Posted By: a493demon

Re: Trans problems... What caused this???? Pics - 09/18/11 11:56 PM

is the shift cable adj. correct ?

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 12:03 AM

Ok here goes;

Burnout 2-3 no problem. Staged in 1st, checked pressure gauge had 200 lbs. Left the lights at 3800. Got out a ways and the engine was bouncing off the rev limiter at 9600 rpms. I then realized i forgot to turn my air bottle on. I shifted to 2nd manually, then 3rd no problems. when thru the lights and pulled it into neutral, but it didn't go into neutral it proceeded to slow down with the engine for about 100 ft and then went into clean neutral. I got stopped, put it in reverse to turn around into the return lane. Put it in first and there didn't seem to be anything there until I hit about 2000. Then I shifted to 2nd and limped to the pits.

Posted By: Dunnuck Racing

Re: Trans problems... What caused this???? Pics - 09/19/11 12:22 AM

Without seeing it in person,it is hard to say for sure. I would bet if you take the return spring out of it,it is bent/broke/or twisted.
High r.p.m's and the return spring unwinding,added up to cause the clutches to drag all the time.

Keith

Posted By: 70AARcuda

Re: Trans problems... What caused this???? Pics - 09/19/11 12:47 AM

Get rid of the single wound spring in the front drum and go with 24 spring kit..

the single wound spring will unwind at high rpms and allow the disc to drag..

http://www.tcsproducts.com/products/product/15/

A&A sells it also

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/19/11 12:51 AM

I would have to agree, 9600 rpm's, youza, that single spring needs to go.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 01:58 AM

Yes I did check the valve body/shifter adjustment.

So the spring is more than likely the culprit? If so this thing has been 39 runs shifting at 8800 rpms. I guess it was a matter of time before something bad happened with it.

Are there any other internals that don't agree with the high rpms that I should look into upgrading while I have the trans apart?

Posted By: CRT

Re: Trans problems... What caused this???? Pics - 09/19/11 02:02 AM

It looks like the front drum piston was touching the rear drum when the front clutch was applyed.
if you have a 4 disc fron drum, and you use a rear drum made for a 5 disc drum (taller splines), when the piston applys the clutches, it will hit/rub the rear drum.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 02:08 AM

The rear drum is a stock 4 disc. The front drum I had 5 thin discs in with proper snap ring for proper clearance.

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/19/11 02:12 AM

I've seen a rear clutch hub made for a 4 disc front clutch not have a long enough hub to engage all 5 disc lugs in the front drum.

Posted By: CRT

Re: Trans problems... What caused this???? Pics - 09/19/11 02:15 AM

In your pics, looks like the front pistion was hitting /rubbing the rear drum. a 904 rear drum for the 5 disc front drum, only takes 4 clutches in the rear drum, but the splines for the front clutch, holds when applyed are taller. Take a pic of the rear drum splines with a ruler.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 02:27 AM

Here ya go

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/19/11 02:32 AM

1.25 is a four disc front clutch drum, I just measured 2 of them.

Posted By: CRT

Re: Trans problems... What caused this???? Pics - 09/19/11 02:46 AM

OK, remove the piston from the front drum, to make sure the drum & the piston are a match set.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 02:47 AM

Quote:

OK, remove the piston from the front drum, to make sure the drum & the piston are a match set.

Maybe a stupid question, How do you know if they are a match set?

Posted By: CRT

Re: Trans problems... What caused this???? Pics - 09/19/11 02:53 AM

904 4 disc drun will have a flat pistion bottom and flat in the drum, a 5 disc will have a beveled piston bottom and beveled drum, I see you do not have the beveled 5 disc drum, so check the piston.

Posted By: CRT

Re: Trans problems... What caused this???? Pics - 09/19/11 02:58 AM

Quote:

Get rid of the single wound spring in the front drum and go with 24 spring kit..

the single wound spring will unwind at high rpms and allow the disc to drag..

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/19/11 03:22 AM

Piston won't be coming out any time soon...

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/19/11 02:58 PM

Might as well get an aluminum or steel drum for it now especially if you are turning it that high. You have to be careful about the 4/5 disc thing though. The 5 disc front clutch trans takes a different rear drum, reaction shaft and input shaft. Good luck.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/20/11 07:36 PM

Thanks for all the info guys. Billet drums are pricey I see. Might have to leave it on the bench for a while.

Posted By: emarine01

Re: Trans problems... What caused this???? Pics - 09/20/11 10:51 PM

Whats the rusty lookin orange color on the front drum & spring? Is that clutch material or rust?

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/20/11 10:54 PM

Quote:

Whats the rusty lookin orange color on the front drum & spring? Is that clutch material or rust?

Not sure what you're seeing on the drum but those springs are painted.

Posted By: emarine01

Re: Trans problems... What caused this???? Pics - 09/20/11 11:02 PM

Orange stuff on the first pic on the inner hub, then on the spring pic, same colour stuff.

Posted By: DemonDust

Re: Trans problems... What caused this???? Pics - 09/20/11 11:29 PM

I think the orange you are seeing is the spring. I don't know what else there is, everything else is silver.

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/20/11 11:30 PM

Quote:

Orange stuff on the first pic on the inner hub, then on the spring pic, same colour stuff.

The spring is still in the drum on the first pics.

Posted By: emarine01

Re: Trans problems... What caused this???? Pics - 09/20/11 11:52 PM

Was the spring painted orange? If so.... never mind

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/21/11 12:37 AM

Quote:

Was the spring painted orange? If so.... never mind

Yeah, that's orange paint or just discolored yellow. Yellow is usually what I see but, I'm color blind too so that may or may not be correct.

Posted By: JohnRR

Re: Trans problems... What caused this???? Pics - 09/21/11 05:26 PM

Quote:

Thanks for all the info guys. Billet drums are pricey I see. Might have to leave it on the bench for a while.

How much is the trans, the floor of the car, your feet, etc. worth ???

Posted By: Guitar Jones

Re: Trans problems... What caused this???? Pics - 09/22/11 02:27 AM

Quote:

Quote:

Thanks for all the info guys. Billet drums are pricey I see. Might have to leave it on the bench for a while.

How much is the trans, the floor of the car, your feet, etc. worth ???

I've never seen a 904 explode the drum, I think the mass just isn't there, but, it's worth the money as has been stated. Besides I don't know anyone else spinning a 904 behind a 9000+ rpm engine so think about it.