transmission issues

[ChildIdenticant]

Vehicle:1994 2wd Auto, 155,000 miles
Issue description:
While parked, running : currently engages in Reverse, neutral, and OD positions with shift lever. Cycling through D, 2, or 1 positions produces no change.

While driving: Feels as though it may be starting in 2 and staying there. Reached 40mph at 3200 RPM, was only able to coax in to 3 with abrupt throttle variation.

Issue history:
My problem started with sticky shifting at various speeds. Sometimes not being able to accelerate beyond 60. But no "slipping". I tested various sensors (mass air flow,vehicle speed, throttle position) and parked vacuum pressures. All produced approved ranges. Found no fluid in the vacuum modulator line so did not replace.
Dropped the pan, about as much debris on the magnet as 8 or 9 pennies, volume wise. no burning smell though.
Removed the ValveBody, some valves were definitely sticky,some galling. Removed all valves , springs and check balls, meticulously bagged and tagged them all with photos. I used crocus cloth to smooth the bores that had apparent issues.
Note:when disassembling the VB there was only 1 puck in there, on the converter pressure relief valve.

I re assembled everything, adequately pre-lubed and attached to trans, brought all bolts to proper torque over many passes in proper pattern (all of my information is from 2006 version of atsg manual). Removed governor which had a tiny amount of internal scoring, also smoothed with crocus.
At this point the only new parts put in , with everything back together were the separator plate gaskets, pan gasket, filter, extension housing gasket.
Filled with 3 quarts (just enough to initially submerge vb) turned on , each position engaged while cycling through with lever, though with some hesitation sometimes. I added another 3 quarts to reach hash mark on dipstick after 20 minutes of idling, and now suffering current issue description. the fluid I put in was castrol transmax dex/merc.
Any suggestion on solutions and what I may have done wrong would be very much appreciated.

And a side note- not one trans shop seemed to be interested in vb rebuild work. Is this common? Thanks.

 

[arco777]

Have you checked that your shift linkage is set up correctly? The shift cable assembly is adjustable, at the bracket near the transmission. There's a procedure to recalibrate it, let me know if you need it.

If it's not slipping, you might indeed have a valve body issue. When I rebuilt mine, I swapped in a lower mileage one from a junkyard X that had suffered head failure at 80K. Seems like once these valves start sticking it is hard to keep them from doing it again. That goes for the governor as well. Clean fluid and frequent changes help, and a high quality filter.

You might want to re-do your valve body with a shift correction kit. I used the Transgo kit in two different A4LDs and an E4OD, all with great results. The kits come with excellent directions, improved valves and springs, and some customizability with the separator plate drilling. I added Sonnax boost valves as well. The kits do specify adding a check ball, which you'd need to source (I used a junkyard valve body to stock up on those).

As for your side note, at least where I live the trans shops are not usually staffed by folks with all their teeth. A hydraulic "brain" is wizardry to them, they're used to the old transmissions with looser tolerances and just swapping friction parts. Valve body work takes time and effort to do right, and the attention to detail is lacking in a lot of people. Also requires a clean workspace. These factors plus the labor times to returns seem to result in shops that don't want to touch valve bodies.

 

[ChildIdenticant]

arco, thanks for taking the time.

Linkage check- Yes. Was able to visually check all positions before replacing the pan, all gears engaged at the proper positions before adding the other 3 quarts. Just with hesitation and not consistently.It still engages just as before for Reverse, neutral and OD, so is there a reason I should suspect that is the issue? I believe I have the documentation on that procedure if turns out to be necessary.

I went to the junk yard once, thinking I had finally read enough to not be surprised anymore by info about this trans. Imagine my surprise when all the explorers on the lot had no 100k spot on the odometer. all 93's with mystery mileage. I'm a bit more determined to fix the one I have now.

I knew of the upgrade/correction kits before taking this on. My thinking on not using them was that this is the first time I have any perceivable issue with my trans, and at 155k the symptoms would be from wear rather than construction. And my governor is freaking immaculate compared to what passed for usable at the transtar warehouse.

Could my current symptoms be caused by a slightly off positioned separator plate gasket?

I admit, having never actually had to deal with this area before I was saying "OH!" quite a bite as I was working on this . But there are many trans shops around here(SoCal, LA county ) and nobody was interested. I also have almost no experience dealing with automotive professionals aside from the required biannual smog cert, so I wonder.

 

[arco777]

Are you certain there's enough fluid? Just getting that out of the way. If you drained the torque converter, then you are going to probably need more than 6qts.

Separator plate gasket should be fine, the bolts usually locate it. Sometimes the gasket kits come with a couple different versions - did you verify it matched your stock one? Did you clean all traces of the old gasket off to avoid cross-circuit leaks?

I'd still suggest the shift kits. They are a real improvement over the factory stuff. I installed them on a couple of high mileage A4LDs (>180k each) and had good results. The truck I still have is at 196k miles and climbing without a rebuild. Granted, the valve body in it only has around 110k miles.

You can also do a line pressure test if you're curious, and check the band adjustments.

 

[ChildIdenticant]

fast forward 4 months....
First, thanks to you arco for advising replies .
I finally was able to solve my problem by:
slightly under torquing the bolts on outside edges relative to the center of the VB during installation. I read this suggestion on a shift kit insert I think.
I also reshaped the solenoid retaining clips so they would apply more force against the solenoids.
I ended up not using the shift kit for the reason I stated above post, and not wanting to introduce more changes that would effect troubleshooting my main problem.
After reinstalleing and kick-down reset,6qts fluid, it works just as it should.