New to THIS forum but so bare with me as I learn your methods.
I'm a Master Tool & Die &Mold maker (22yr) and A & P licensed mechanic. I can't seem to find the diagnostic info I desperately need to solve this trans problem.

Truck: '02 F150 4x4 5.4 150K.
Problem: Started to notice a delay from reverse to DRIVE. Then notice neutraling during torque commanded downshift from 4-3. (I usually drive around with OD=OFF unless on the highway).
Delay seems to be WORSE the longer it sits. (ie 10 hrs sitting = 45 second delay VS 1 hr sitting = 20 second delay)

Once the tranny is "ENGAGED" all forward and downshifts are NORMAL (od=OFF)

Scan = NO CODES, no blinking lights...clean
What I did:
1. Change fluid n filter = NO CHANGE
2. Open pan again.. check 1-2 accumulator and springs (good), 2-3 accululator and spring (good), VB gasket and separator plate for damage (good), OD apply piston ASSEMBLY (replaced with oem unit modified with O-RINGS like sonnax). = NO CHANGE

I have been all over the WEB searching hence the check list, but have yet to find either the same problem as mine OR NO REPLY WHEN ITS FIXED?

It SEEMS to be related to the forward clutch as ONLY 1-2-3 require it to engage. OD and reverse require it to disengage, I think.
any and all help is much appreciated as I'm really about out patience and motivation to solve this PITB.

 

I think you have a damaged forward clutch.

 

but what changed/happened? 1 day great.... next day,, SUX???

It still snatches 2nd and 3rd ...... well it lets you know it SHIFTED...with enthusiasm..
I have NOT ran pressure tests..yet as I do not have 6ft of line to run guage up to windshield....YET but I will very soon. Such a PITB ..

 

My guess is that the piston seal in the clutch failed. It isn't required to provide notice that it's going to fail. That was not a design criteria.

The forward clutch isn't involved with either of those shifts, so I wouldn't expect it to change anything there.
That should show something.

 

super excellent!
THAT is what differentiates those that know WTF they are doing vs those that ALMOST know.

That fits MY train of thought and fits within the parameters of the problem. Soooooo many folks I have bothered asking can't see past the 150k to say.."oh it's toast...you need a rebuild..." well actually I don't!!!
I have a SINGLE COMPONENT FAILURE. (yeah if I open it up I will rebuild it...duh) but KNOWING WHY it isn't working is the difference because.... that means everything else IS doing its job correctly,

 

I finally got a hydraulic circuit layout for this. And an exploded assembly view. I'm guessing that since the truck does not slip in any gears. ... once engaged, that the forward clutch piston is probably ok BUT the wave plate is broken. This should show up once I take pressure reading s.

 

Just curious to try and understand your thinking on how a broken wave plate will show up on pressure readings.

D

 

My understanding is that there is a wave plate (spring) within the clutch pack. This should act as an accumulator allowing the clutches to "slowly" engange . This also takes up stack height in the assembly. Until I take pressure readings this is all shooting from the hip.. (guessing)
Since 1st gear has NO recognizable slippage once engaged (ie I just pulled a BOBCAT last week) I should think the forward clutch piston is engaging properly AND holding clutch pressure correctly; however, the distance it must travel to APPLY said pressure may have increased tremendously. (hence the delay) OR something a simple as a seal relative to the exhaust circuit could be leaking allowing the circuit to exhaust completely DRY; therefore, causing a severe delay in piston apply pressure as the circuit must "prime" first.

Again just narrowing it down with more info and testing procedures. I'm currently preparing to pull it but first gotta get the old Bird road worthy.. (Trans Am firebird that is..) as the truck is my DD.

Thankyou for the replies as I'm 10000% open ears.

btw it was my understanding that the forward clutch STAYS engaged during 1st, 2nd, and 3rd! only to disengage for o.d, N, and Reverse....?

 

Would a quart of seal softener help it temporarily Darrin?

 

MORE info ... this just in.. pressure tests

idle line pressures
p=62
r=120
n=52
d=90

wot stall forward clutch pressure = 210

idle FORWARD CLUTCH TAP
d=.....????? when D is selected guage goes from 0 -> 10 psi immediately...then about 1.5 seconds goes to 50 psi. and STAYS THERE.... until I rev the engine ( I blip the throttle..only) to see about 100 psi...then the forward clutch will engage.

also noted: when OD engages forward clutch pressure = o ...then when I let off throttle, turn OD->OFF ...forward pressure goes to 55..until I rev engine..then jumps to 90 and is engaged.

NOW... this points to a couple problems...I think.
1. The valve body is NOT allowing full line pressure to the forward clutch OR
2. Possibly the forward clutch piston is not sealing until it is"slammed" with excessive pressure....then it is able to "maintain" it's seal until pressure is exhausted. (seal related)

 

It could be a sticking check ball in the forward clutch, damaged piston seal, sealing rings or a hanging valve.

Easiest way to start is in the valve body, but I think that if you find a problem there that you have a bigger problem elsewhere.

D

 

concerning the forward drum apply piston: If the lip seal has deteriorated it would seem unlikely that it would continuously HOLD pressure. (once engaged the forward pressure never drops below 90) The fact that the pressure is only 55 until I rev it makes me believe it is in t he valve body related to fluid directing. Ah thoughts to ponder?

 

Maybe. However, I have definitely seen damaged lip seals cause this. They get hard and won't seal until there is a lot more pressure on them than they should need. Eventually they crack or pieces break off and cause total failure.

So don't rule it out yet. It's still a likely cause.

Regardless, this isn't something that can be thought out. It is what it is. You have to choose your starting point and if that isn't yanking the while thing out for a rebuild then I would look at the valve body.

As to a seal softener, only as a last resort to maybe give a dying transmission a last run or two down the road. Probably isn't even going to do that though. But if you are at a "**** on a spark plug" because you haven't got anything else point, it isn't going to kill the already dead.

D

 

Hmmmm....that makes me think it's a damaged seal. When you rev it the pressure and flow increase, and that's enough to get the piston to stroke even with the leaking seal. Once it's applied the seal will hold. I've seen this happen many times.

 

Thanks Guys this really helps evaluate the problem. Now I can concentrate on getting the appropriate supplies together to resolve this.

Plan A = master rebuild kit with new solenoids.
Plan B = rebuild + step up above stock... ???

It's been 25+ yrs since ive done an automatic.. from what I have found there seems to be several variations of components. Raybestos, Alto, Borg Warner, Ford...

only 1 question left?

Should I have the local converter rebuilder do MY converter or buy a repop from Daycco, continental.. etc?

Basically Stock 5.4 ...going to stay that way!!! with 4.30's on 35" dual duty daily driver/troop transporter.. (5 scouts here ... we live in the woods n trails)

http://www.bulkpart.com/2/product/AO...6HW-BOX-1.html

http://www.oregonperformancetransmis...=ORE-AODE-RBHP

I've become very familiar with Jerry's tech info on TCCoA (btw Darrin... your name is all over the ford blogs too) and plan to follow said info closely during my build.

Again Thanks guys for your precise input to my problem as this helps ME tremendously!!
I hope I can further the cause by replying AFTER my teardown.