Rebuilt A4LD and might have a problem...

[BobWeiss]

I just finished installing my tranny (A4LD) back into my 91 X and took it out for a test drive. Everything seemed to be fine and all shifts were nice and smooth! After going around the block I pulled it back into driveway and put it in park and tested the fluid level for the 10th time and everything is good.

Next day I start truck and drive to work. On my way in I drive on a major road which you can do 60mph on and the truck still ran great. I even have my OD gear back. (One of the major reasons for rebuild).

At lunch time I go out to take a quick trip and it backed out of the parking spot ok but wouldn't engage in drive. I tried OD, D, 2 & 1 and nothing. I tried reverse again and that worked fine. After messing with this for about 30 seconds I was able to move in 2nd. I then switched it to OD once I got going and it ran fine the rest of the way even if I stopped at a light.

What do you think would cause this? I practically put everything in new. New solenoids, new VB rebuild kit, new OD planets and sprags etc.... The only thing used was the Forward and reverse drums.

Any ideas? I am going to see what it does after work...hopefully it works fine.

Thanks,
Bob W.

 

[dogfriend]

Check fluid level again? Maybe all of the fluid wasn't circulated until you engaged all of the gears?

 

[BobWeiss]

Thanks for the reply. I checked it again and its good. I did however narrow down the symptoms to the following:

It only does it when I first start the truck and its been parked for awhile. It will work in reverse just fine and also in 2nd. All other gears won't go. The strange thing is though that once I am moving I can put it into Drive or Overdrive and it works ok unless I come to a stop. This only happens though for about 10 minutes then it works normal. I think this has something to do with the tranny temperature. It has to be warmed up first.

The manual says it could be a number of things and I ruled out about 1/2 of them right away. The only things I can think of is that the linkage is messed up (but that doesn't make sense because why would it work when it warms up and not just do it all the time?) and the other thing could be a dirty valve body or sticking valves. I did disassemble the entire vb and clean each bore and valve and used vaseline to re-assemble along with installing the transgo shift kit. I made sure all valves moved easily in each bore.

So this is strange...anybody have any ideas where to look or what tests I can do? I don't have a pressure guage so I can't do that one.

Bob W.

 

[BrooklynBay]

I would suggest that you buy a pressure gauge, and see what your pressure is when this problem acts up. When you torqued the VB bolts, did you go in a row, or at a random sequence? Some bolts might not have been torqued consistently (assuming you used a torque wrench to tighten them).

 

[BrooklynBay]

I couldn't find a diagram of the torque secuence for the A4LD in the photo gallery, but found one picture of this for a 5R55E in Glacier991's photos:

 

[BobWeiss]

BrooklynBay:

I did indeed torque those bolts in the order the manual says. I double checked them too. I used a 1/4" torque wrench and set it at 100inch lbs. The manual called for 95-107 inch lbs I believe.

If I do get a pressure gauage how do you determine what pressures are right? Where do you hook it up to the tranny?

I have this feeling that it has something to do with temperature but I can't figure out what area would be affected by this...


Bob W.

 

[BrooklynBay]

This thread explains how to use a 0-300 PSI pressure gauge: http://www.explorerforum.com/forums/showthread.php?t=117998

 

[BobWeiss]

Nice link!! Thanks.

I will pick up a gauge this weekend and see what I am getting during driving conditions and cold starts.

I just took the truck out a ride after it has been sitting for 2 hours and it worked great right away in OD and D. So this is definitly a hot/cold problem. Something changes when the tranny fluid temp gets up to operating range. Maybe a seal is leaking when fluid temp is cold then it swells the seal and stops the leak as you drive???

Just throwing ideas out there...

Bob W.

 

[Glacier991]

Did you use seal protectors on reassembly ? I'm curious too to know your pressures... this does sound either like a sticking spool in the VB, or a leaky seal to me. VB's can be tempermental beasts.

 

[BobWeiss]

Yes I did use those seal protector's when I installed each piston. I also did the air test on each one and made sure I didn't exceed 20lbs of pressure. They all moved nicely. I also made sure I was within the specs between the c rings and pressure plates.

My thoughts are that its something in the VB because since its only doing it when its cold and when its hot it shifts nice and smooth on all gears. I had to remove the VB after initially installed it because I decided to do a full rebuild. When I did that I scraped off the top gasket between the vb plate and the tranny case and installed a thicker one. I used a gasket glue to hold it in place the first time so there were some stuck pieces and I'm wondering if a tiny piece fell into one of the holes. This is a strong possiblity and I wonder if this would cause this issue. But why only when its cold??

I am going to run it for a month then drain the fluid and drop the VB to check it out. I did disassemle the entire vb and clean each bore one by one and upgraded the ones that the shift kit said to do. I also replaced both soleniods and used the sonnax end plugs with a round o-ring on them. I followed your diary to the Tee when I did it.

Bob W.

 

[Glacier991]

I vaguely recalled. You have done everything you can, and i support the hypothesis of the VB being the issue. I have rebuilt quite a number, and now have had 1 A4LD body come back and 1 5R55E. Did I cut any corners? no. Have I figured out the problem in the 5R55E VB, I think so... as for the A4LD VB, not really. I took it all apart and it all seemed fine.

If you have the FORD 3 ring binder (it seems you might) check the hydraulic circulits in it, and isolate each companent and check it carefully. In other words... I'd jump into the VB. If you need a pressure gauge to borrow first, PM me.

 

[BrooklynBay]

Check this thread: http://www.explorerforum.com/forums/showthread.php?t=126461

 

[BrooklynBay]

Could you list the modifications made to the valve body such as installing shift kits, rearranging check balls, drilling out bores, etc? When you rebuilt the transmission, did you use lip seals on the internal pistons, or the older style "D" rings? There were other changes made as described here: http://www.explorerforum.com/forums/showthread.php?p=1521552#post1521552

 

[BrooklynBay]

This is what I was referring to in my previous post (photo courtesy of Alyz1flr):

Notice the older design "D" ring seal on the left, and the newer lip seals on the right. The lip seal is also facing away from the piston where the springs are going into.

 

[BobWeiss]

If you have the FORD 3 ring binder (it seems you might) check the hydraulic circulits in it, and isolate each companent and check it carefully. In other words... I'd jump into the VB. If you need a pressure gauge to borrow first, PM me.

I do have the manual and took a look at each circuit but without 100% knowledge of tranny's behind me its not easy to figure out.

I was thinking of picking up a used vb and replacing this one just to see what happens. If it goes away then I know what is wrong and have to isolate the problem bore.

Bob W.

 

[BobWeiss]

Could you list the modifications made to the valve body such as installing shift kits, rearranging check balls, drilling out bores, etc? When you rebuilt the transmission, did you use lip seals on the internal pistons, or the older style "D" rings? There were other changes made as described here: http://www.explorerforum.com/forums/showthread.php?p=1521552#post1521552

I did indeed read that thread awhile back.

I used D rings on the reverse servo and the other 2 I used what looked like regular o-rings to me. They came in the rebuild gasket kit I ordered.

As for modifications I followed the Transgo shift kit instructions and also added 1 more ball to the vb like it said. I drilled the hole in the vb and I also enlarged a hole in the plate. (I have to go back over the directions to see exactly where it is)

I also replaced the end plugs with sonnax ones and upgraded the boost valve and put the sleeve on the manual valve to correct the oval wearing it had.

New hocley pucks and balls, new type pressure relief valves (the 2 that have springs pushing it up and hitting the plate).

If I htink of any others I will let you know... I have to get the directions out and they are at my house.

Bob W.

 

[BobWeiss]

Update:

Ok this morning when I started the truck it went right into drive and worked flawlessly. Its been fine all day. (went out for lunch).

This is getting stranger as it goes on...although I will take it as long as it is working fine.

I am beginning to think its the vb with a piece of gasket material that fell in and now is dislodged from where ever it was. Does the fluid get thinner as it warms up? (like engine oil). If it does that could explain why it worked after running for a bit, more fluid would be able to get by the obstruction don't you think?

Anyways, I am keeping my eye on it and see how it goes the next few days.

I saw on ebay I can get a used vb for $25 and I could rebuild that one and switch over the soleniods etc to it and see what happens... a cheap way to isolate the problem I think.

Bob W.

 

[dogfriend]

Yes, the trans fluid changes viscosity (gets thinner) as it warms up. I have a stacked plate auxillary trans cooler that works on this principle - it bypasses the cooler when cold, but flows through the cooler when warm.

 

[BobWeiss]

Update:

The truck is still running fine and today when I started it it was around 60 degrees outside which is alot cooler than it has been. I put it right into OD and it worked great. The only thing it did weird was that it took a long time to go into 2nd from 1st. It only did that 2 times in the beginning.

Does anyone know what it could be given these conditions now? I am hoping its all related and narrows it done some.

Bob W.

 

[BrooklynBay]

You might have a sticking governor, bad modulator, stuck valve where the modulator pin goes in, and out of, or a misadjusted intermediate band. Check the vacuum line going to the modulator for vacuum. Make sure that there is no vacuum leak by the vacuum connector (octopus).