Moparts I have been fighting with this 904 since day one. last fall car made one pass smoked the pump. Since then new clutches, pump etc. I put back together trans slips. I used an old manual for rebuilding the trans for the adjustment and not sure what I did wrong so I want to ask again before I drop the pan.

Front band inch pounds and back turns
Rear band inside the pan inch pounds and back turns

Some guys say tighten till snug thean back out, "WHATS SNUG?""

Please give me some insite.

Kiddart

problem is for 72 inch pounds (6 foot lb) most torque wrenches are junk and way over torque. I heard the only ones that will do it are good needle dial ones.
anyways front band what I call wrist tight (snug) with a 1/4 or 5/16th wrench not hard to get just a nice wrist snug.
Then back front band off 1 3/4 turns if it's too loose it will slip into second.
rear band same but back it off 2 1/4 turns

will a loose band make it slip when you add some acceleration?? I am guessing it would.

Sorry for the spelling

Kiddart

It really should not make it slip except on the 1 2 shift. both bands are released for drive/3rd
Unless the front or rear band is hanging up.

a lip seal that is folded is the likely culprit and air test should show it.

How do you air test?

727 and 904'a are the same

Did you have a complete trans to start with?
I have been building race 904's for 40 years and if you piece a 904 together a 904 the problem is there are 6 different combinations between the 904,998.999.and the 518 that all look alike but the passages for oil flow go in different directions and they use different sealing ring. All parts need to be matched. The sealing ring on the input shaft are even different sizes. Check all that out. If you are still having problems call me. 563-349-7412.
Thanks
Jim Petersen

you have to have a rubber tipped air gun as you test front and back clutches they should make a nice clunk (as clutches apply) with not to much air escaping past seals.
you can apply front and rear bands too to see function.

Accumulator piston must have new / good sealing rings weather it is used or blocked or pressure will leak past them.
http://www.summitracing.com/parts/MLI-S-153/

thanks all!! its a complete unit that I bought from a very good builder on this site. I have just run into a string of bad luck with the car. Since I put the motor in I cant seem to keep a trans in the car. Ready to sell everything and start over. I know it cant be anything huge, I built the trans in my dads car and that has lasted a while and its been used alot thats for sure. I will keep at it, the trans has all the good stuff from A and A and Cope. They have helped a bunch to

You never did answer the basic question...under what conditions does it "slip"?

under load

sorry guys, I am afraid to drive it. It seems to be ok in reverse but I dont hammer the gas to back it into the garage. if I give it gas in all 3 gears it slips. I hits going into first slides into second and hits sorta going into third. I have no time this week to get into this due to baseball softball volley ball and oh I forgot work and then spending time with my wife. I do apprecioate all the help I am getting here thanks and keep the knowledge comming.

If this helps I have an all indy built sb that has about 680hp at the crank. I was running a 5k stahl then just went back to my 4500. any of this may or may not help.

it looks like its going to be comming out again. big bummer for me.

Kiddart

I'm going to ASSuME it's not a stock rebuild 904 with that much HP ???

If it's slipping in all forward gears a band adjustment is NOT going to fix it .

your assumption is correct. It was fine untill the pump went. it hit hard and quick. I will figure it out. I am going to do the pressure test this weekend and if it has to come out then so be it.thanks for the input guys.

When you replaced the pump did you tear the trans down and completely clean any debris out that may have been created by the failed pump ?

The rings on the accumulator are important even if it's blocked! if they leak no pressure slips in all gears.

I once had the pump housing bolts come loose well they never got really tight. when to get a socket I liked, then went in the house to wizz, played on the computer then went back and assemble the tranny it did not go far!

Have seen sealing rings get broken putting pump back in it will show up in air test!

Did you match the pump?There are a few styles.The pumps should look identical.They also changed the the lug pattern on the pump gear.
Hook a gauge up and check your line pressure.

when the pump was sent to the builder so were the drums, and valve body. The builder then repacked the drums with all new clutches and steels then went thru the valve body, a new pump was ordered at the same time from the same shop. he then sent to me and I reinstalled into a freshly washed and blown dry case. I would guess its a ring in there some where. if not it will all go to a trans shop and I will spend another few hundred on a rebuild for a rebuild?? see why its frustrating to me. I will win the battle i promise you that.

Do the air test first most often points to the problem.

I will for sure. thanks for all your help. I learn new stuff on here every time I ask for help.

I need to do my low/rev adj on my race 727 so i need to be sure the snug will work on the adj stud,so that is correct to get it snug?then back it off,lock it down?I cant find a socket to fit it!

Quote:

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problem is for 72 inch pounds (6 foot lb) most torque wrenches are junk and way over torque. I heard the only ones that will do it are good needle dial ones.
anyways front band what I call wrist tight (snug) with a 1/4 or 5/16th wrench not hard to get just a nice wrist snug.
Then back front band off 1 3/4 turns if it's too loose it will slip into second.
rear band same but back it off 2 1/4 turns

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I just use a 1/4 or 5/16 wrench and the jam nut is 5/8" I think and 3/4 on the front band.

Just wrist snug then back it off 2 to 2 1/4 turns low reveres can be looser as it is gust to apply reverse or low hold.

The front band has to stop the front drum to shift into second.

Thank you very much!That is very helpfull.

Hi moparts I am going to reserect this one. I finally had time tonight to do the air check. when i do the air check I hear a high pitch whistel in the front clutch hole and I hear a soft clunk in the rear clutch apply.when I do the front and rear servo apply I see the band tignten. Any thoughts on what it can be???

I know its been a while but at least I am at it now.

thats my thought as well. It comes out AGAIN. This must be the 10th time. At least I am getting real good at it.

What double R said, it was fine till the pump failed & not sure how a pump failure could cause subsequent problems (once you fixed the pump of course) other than debris went everywhere. Yes I'd totally strip it & clean every nook & cranny surgically clean then blueprint all subsystems back together.