low/reverse air check 2004r

cdw1946

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Joined
Feb 28, 2014
been away for awhile and just got around to air checking my low/reverse during final assembly. the frictions lock up when air is applied and unlock when i remove air pressure but there is also a lot of air hissing with the air on. is there an exhaust where the air exits when this test is performed? new seals and frictions installed. thanks, denny
 
Did you air check it when you put the spring and piston in? Are you now putting air in with it all in the case and squirting air from the bottom "worm casting"? I would think it could loose some pressure where the clutch assembly is lined up with the block as there is just metal to metal there as it is just the exhaust.

I'm sure the gurus will be along with a better answer. But if I checked it when I put the piston and snap ring in and it snapped good I would be happy.
 
Probably either forgot the rubber tipped cup plug in the case or didn't hammer it in tight enough. If that's not the case then there's a problem with the seals on the piston.
 
been away for awhile and just got around to air checking my low/reverse during final assembly. the frictions lock up when air is applied and unlock when i remove air pressure but there is also a lot of air hissing with the air on. is there an exhaust where the air exits when this test is performed? new seals and frictions installed. thanks, denny
You should get zero leakage when testing lo/reverse. When you apply lo/reverse with air, it should hold with no air until air nozzle is removed. Make sure your air nozzle is making a good seal.
 
Agree with that if you don't have a rubber tipped blow gun use one of the pistol style blow gun with the removable tip, if the tip doesn't fit in there very well, pull it off and use a red rag to seal it off,it should make a good thump and you should here no air coming out, if you do, pull out assy. and air check on bench,if you still hear air put a little trans fluid around the piston where the seals are located and air check again,if they are leaking,the fluid will show you where.Good luck.By the way if you pull it out of case to test it only apply enough air so you can see the fluid bubbling,dont allow seals to come out of housing or test is no good.
 
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You should get zero leakage when testing lo/reverse. When you apply lo/reverse with air, it should hold with no air until air nozzle is removed. Make sure your air nozzle is making a good seal.
thanks,i'll recheck the rubber tip on the hose. rubber tip plug is installed. i had about 60 psi in the hose but i forgot that the hose and lines is about 100 feet away from trans. probably some resistance in the lines.
 
You should get zero leakage when testing lo/reverse. When you apply lo/reverse with air, it should hold with no air until air nozzle is removed. Make sure your air nozzle is making a good seal.
i had been away from this project for about 3 months and i should have checked my notes,which i did last night.i had checked the low/reverse clutch assembly after the modifications on page 85 (chris's book) and everything checked out good. thud when pressure is applied and retracted when pressure taken off. no leaks. book said double up on the wave plate and drill .060 bleed hole in clutch housing which i did. installation into case was pretty straightforward. feed hole alignment was ok.just went out to recheck and had some air hose problems which i corrected. still have a lot of air hissing coming out and the clutched locked and unlocked. is the seal as tight when assembled as it is when checking the low/reverse housing assembly by itself on the bench? was ok when bench tested but a lot of air noise when assembled. thanks
 
Did you use any kind of assembly goo on the seals when you put it together? I was told to use it liberally all over the place to try to minimize a seal getting torn. Yours might have dried out and the rubber isn't sealing well. I would pull it back out and see about it. Way easier now than pulling the trans again.
 
Sure it's not the air exiting the .060 bleed hole you drilled?
thanks for the reply. did not bleed out on the bench when checked. i had a previous reply on the rubber tip on my air hose. i'll have to fabricate a smaller tip,mine is just too big, i can't get it to seal against the cup plug very well.
 
Its probably alright, buy a vacula or one of the air nozzles that has the removable tips and use a red rag. Heres a good food for thought tip, if you rebuilt the trans and your not a trans builder per say you just want to build your own[which im a fan of] if you pulled the unit down and those clutches weren't burnt, and they air check on the bench you have a real good shot at the fact that there isn't a problem in that circuit put it back in and go for it. The only time I worry about a particular circuit is if I pull the unit down and that set of clutches is burnt I start lookingfor the smoking gun, in other words what caused this, but if they weren't burnt when you pulled it apart and they air check on the bench, put it togother and run it, the worst thing that can happen is you have to pull it back down again and check it, but guess what all your doing is learning every time you do this,thats why were car guys right? Good luck im sure you will whip this.
 
Question on this , what does the trans act like if you have this problems here , just had a trans done and it has no reverse now but forward gears are fine , which seal would be bad ?
 
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Question on this , what does the trans act like if you have this problems here , just had a trans done and it has no reverse now but forward gears are fine , which seal would be bad ?
Its hard to say especially right after a rebuild because instead of the trans going down the road for a lot of miles and the normal things happening, this, im assuming, happened right after the build, so this is self induced, could be that the seal between the valve body and the case isn't there or he pinched or cut a seal in rev. clutch piston or the direct drum as both of these clutches are applied in rev.
 
im assuming, happened right after the build, so this is self induced, could be that the seal between the valve body and the case isn't there or he pinched or cut a seal in rev. clutch piston or the direct drum as both of these clutches are applied in rev

Yes this happened right after rebuild , since 3th and 4th gears are working wouldn`t that tell me the direct clutch is working , so likely the seal is cut at the valve body and case or reverse piston seal pinched or cut ?
 
Paul`s Transmission , a racing trans speed shop in my area
The reason I ask is all of these things could cause no rev. it could even be something as simple as the boost valve or one of the other valves hung in valve body,hard to diagnose something like this not in person especially since it is obviously self induced. Things just happen no matter how good of a builder you are, if it is a reputable shop they will fix it.
 
The reason I ask is all of these things could cause no rev. it could even be something as simple as the boost valve or one of the other valves hung in valve body,hard to diagnose something like this not in person especially since it is obviously self induced. Things just happen no matter how good of a builder you are, if it is a reputable shop they will fix it.

Thanks I understand , we will see what he says
 
No problem, good luck and report back with what they say it was.

The trans is working in reverse now after driving it some , only thing it does now after it was driving a while sometimes it would chatter for just a brief second in reverse maybe 1 time in 5 engagements , seems to be better each time driving it , it has 6mo or 6000 mile warranty so the guy said he would do what ever if it got worse
 
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