Problems After Valve Body Rebuild

[Longjohn119]

I'm having a problem with overdrive after a valve body rebuild ... it doesn't want to shift into OD unless I completely let off the gas, as soon as I pick up the throttle again it goes back to third gear ...

Everything else works fine, 1-3, converter lockup, kickdown, engine braking (I also put new seals in the low/reverse servo) ... in fact they work better than ever, nice crisp shifts without being harsh just no OD ... also it worked fine before the rebuild, the only issue i had before was the reverse/low servo leakage (Delay into reverse, no engine braking)

So I'm looking for a second opinion here ... I figure either I accidently plugged up the 3-4 shift servo when I cleaned it (It seeems to worked electrically) or I have an issue in bore 202 and/or bore 201

I've already resigned myself into having to drop the pan again and perhaps even the valve body but would like to only have to do this one more time ...

Any ideas or suggestions would be appreciated

 

[Longjohn119]

Bump ...

Hmm, might have to fly solo on this one ... wouldn't be the first time ...

 

[Glacier991]

LonhJohn... sorry I have been on vacation for 10days and just got back. Let me look into this tonight and let's see if we can't come up with some possibles.

 

[Longjohn119]

Thanks ... I was going to start again tonight but it's just too hot ...

Everything worked fine before although that doesn't completely eliminate a bad OD servo ... more likely it's something I missed in the valve body or the solenoid valve is plugged ...

Definitely going to put a drain on the pan this time, never could figure out why there isn't one on it from the factory other than greed to make an extra 50 cents profit on a $25,000 vehicle (When I first started saying this you could get a new F250 for under 5 grand) ...

 

[CDW6212R]

I wish I could help, but I have little knowledge of A4LD's and their decendants. Good luck to you and Chris. I'll keep an eye on the thread. Regards,

 

[Glacier991]

Okay... let's think.... valve body rebuild is all you did. Certainly if we have OD issues, it means we are not getting the OD band applied for some reason. let's go through the hydraulics (why I needed to be home, I have to have the book in front of me). here we go

Hydraulic flow... OD- (4th - locked)

1. Line pressure from the pump

2. manual valve (206) directs fluid to governor, 2-3 backout valve (211) and the low reverse band release side. [note like in damn near every gear].

3. Governor pressure continues to increase with engine RPMS [same comment]

4. The 3-4 shift solenoid (202) is energized to move the 3-4 shift valve (201). This applies the OD band with direct line pressure. The OD servo exhausts through the OD servo release accumulator (216) to cushion the band apply. The fluid then exhausts through the manual valve (206).

5 and 6 are convertor clutch issues, so I will omit.

All of this is hydraulic only... possible electrical issues also exist.

Some random thoughts. A) I'd love to know line pressures as the transmission operates. B) Your thoughts regarding the solenoid are valid... Brain suggested spraying brake cleaner through the solenoid as you cycled it electrically.... I'd add follow up with lubricant the same way. C) Did you use a torque wrench and new gaskets? (hit me, I had to ask). The fact it worked fine before the VB rebuild "kind of" rules out the servo piston.... takes me back to A.

How was the VB on disassembly? And the 201 bore in particular? And in Bore 202, did you get the nib on the spacer plug pointing OUT towards the 3-4 solenoid?

Also we need to consider bore 216.


Random thoughts, but a place to start.

 

[Longjohn119]

I did clean the solenoid, I cycled it but didn';t really know how to test the ports (Thanks to Alldata I do know how now) ... pulling it and testing will be my first step ...

I didn't have an inch lb torque wrench available at the time, my garage was broken into in May and it was stolen, went to 3 chain auto stores and no one had one, only ft lb ones (which I find stupid) ... Got one at Sears (Craftsman, manly man tools) and plan to retorque the valve body per the A4LD-JR directions, even if I do find the problem is the solenoid

VB was in excellent shape, as was the fluid on the first change in May, vehicle was serviced by the dealer at recommended mileage, I got the records when I bought the truck (It's also how I know it really has only 57,000 on it) The lady who bought it new kept it well maintained

So I really didn't have an issues rebuilding it other than the same one you had with bore 211, it just wasn't coming out so I left it be but obviously that isn't the problem. Gaskets are new, got the soft parts (gaskets, o-rings, etc) kit from transtec ... that being said bores 200-202 were the last ones I did Friday night before calling it quits at midnight, drilled the serarator plate and the rest Saturday

So the plan is drain, pull the pan, install the drain plug Ford Motor Company can't afford (pun intended), pull the 3-4 solenoid, reclean (BTW I have the 2nd style, no screen) and check it, replace if necessary, loosen and retorque the valve body, reinstall pan, refill and test ... if it doesn't work, redrain via the drain plug Ford Motor Company can't afford and pull the VB

Found the typical insanity pricing the solenoids ... Borg Warner TCC and a Neihoff TCC, owned by the same company, exact same solenoids made in the same plant, prices are from the same parts supplier (Advanced Auto) Borg is 78 bucks, Neihoff is 52 bucks ... not a nickel's worth of difference between the two other than the name tag ...

I'd like to see some suit justify that nonsense ....