[Sea-J]

Over the winter I replaced the accumulator 0 rings in the A243L trans to cure the shudder shifting 1-2. The fix worked as far as I can tell since I haven't had the car out for a long run yet this year. After the fix I backed out of the garage without issue, about 50ft. and shifted into D and went right back in the garage.
Since the car is in winter layup I start it up once a week to keep everything moving. Since the initial backing out of the garage I no longer have reverse. During the transmission 0 ring replacement all the fluid lines were blown clear to push out the accumulator pistons. Now when I "shift" into reverse I get a slight nudge and then no movement. Forward gears work fine. When I do shift I hear a short "gurgling?", hard to describe. and then it goes away after about 3 or 4 seconds And everything is fine in forward. Sounds like there is air in the lines or pump. Anyone know how to purge the air out or would a long drive to heat things up solve the issue. Checking the websites say to run the car with the transmission dipstick removed to let any air escape. I replaced the recommended fluid, calls for about 8 qts (US). First fill took about 6 1/2 quarts, (stick indicated full) After resting for a few days I had to add another quart because the dipsitck read low. Assumed the fluid is slowly filling in the gaps. I strongly think there are passages that are still airbound.
Suggestions/opins?

 

[sefiro]

I don't have an automatic 5th gen, but have worked on many a transmission. Pulled up the rebuild manual looking for hydraulics flow discussion , nothing. So. . .

• to flush an automatic, you can use the oil pump to pump out old fluid. Disconnect the output oil cooler line from the radiator (could be standalone or integrated into the engine radiator). Connect a hose to the line and point to a 5g bucket. Start the car, run for a minute or so. Off. Refill tranny. Do again. Continue until bright red fluid starts flowing into the Bucket. You'll want to shift thru the gears to get as much out as possible. ThIs will get 95-98%. The remaining is in areas of the valve body that were not "operated" as the ecu did not receive signal that the car was moving.
• as for the no reverse. You mentioned blowing out the pistons. Where these the accumulators or the those behind the solenoids?.The C2 accumulator/clutch controls the reverse direction of the intermediate drive shaft (c1 forward, c2 reverse). ThIs piston might have lost its oring, cracked, broken spring.(fluid is directed on 1 side of the piston pushing it towards engaging the clutch. ) the piston won't move if the oring is gone. If the spring is gone, the assist on engaging/disengaging won't happen or the piston could get cockeyed and stuck.
• outside chance that the shift cable wasn't properly connected so the manual valve won't shift (ie, it is stuck in forward)

Sent from my Pixel 5 using Tapatalk
View attachment 32527 View attachment 32528

 

[Sea-J]

I don't have an automatic 5th gen, but have worked on many a transmission. Pulled up the rebuild manual looking for hydraulics flow discussion , nothing. So. . .

• to flush an automatic, you can use the oil pump to pump out old fluid. Disconnect the output oil cooler line from the radiator (could be standalone or integrated into the engine radiator). Connect a hose to the line and point to a 5g bucket. Start the car, run for a minute or so. Off. Refill tranny. Do again. Continue until bright red fluid starts flowing into the Bucket. You'll want to shift thru the gears to get as much out as possible. ThIs will get 95-98%. The remaining is in areas of the valve body that were not "operated" as the ecu did not receive signal that the car was moving.
• as for the no reverse. You mentioned blowing out the pistons. Where these the accumulators or the those behind the solenoids?.The C2 accumulator/clutch controls the reverse direction of the intermediate drive shaft (c1 forward, c2 reverse). ThIs piston might have lost its oring, cracked, broken spring.(fluid is directed on 1 side of the piston pushing it towards engaging the clutch. ) the piston won't move if the oring is gone. If the spring is gone, the assist on engaging/disengaging won't happen or the piston could get cockeyed and stuck.
• outside chance that the shift cable wasn't properly connected so the manual valve won't shift (ie, it is stuck in forward)

Thanks for the suggestions. Blew out the accumulator pistons. Two came out on their own the third needed the boost. Did get a chance to take it out for a good run today, temps in the low 70's. Ran perfect, smooth shifting 1-2-3, OD. Did manual shift up and down, perfect, kickdown passing gear engaged, no shudder on up shifts, just no reverse. Looking around for a reputable local shop, I'm thinking the new 0 rings and more positive shifting stressed the 269k innerds. I'm not a tranny guy and the accumulators on the A243L are easily serviceable. Right out front. There was a lot of metal dust on the magnets when I dropped the pan.
It did go into reverse the first time I backed it out of the garage after the change so I know the linkages etc. are right. but then never would reverse after that first time.
I'll toss a few bucks at it now so It'll be drivable, Hate looking for parking places where I don't have to back up

 

[Sea-J]

Forgot to mention I will try the flush method, didn't think of airbound radiator cooler.

 

[elliotgofast]

There is usually a breather port on the top of the transmission. Either a fitting with a loose cap or a hose that loops down and doesn't connect to anything. I have never heard of pulling the dipstick out to help purge air as you need some airflow for warm and cool down of the fluid. So you might need to make sure the breather for the housing is working properly. You really need to get the transmission up to temperature to understand fluid level. You can probably idle on the driveway for hours but the goal is to get the fluid warmer than 140F. It might require sitting on jack stands and running it through the gears with no load on the tires. Using a laser temperature gun on the transmission pan will help to understand if the fluid is warm enough to get confidence in the reading. Warm fluid is lower viscosity so it will flow and move easier into the nooks and crannies and running it through each gear including the manual selector positions below D help to fill every cavity. Once your confident in the fluid level, then further diagnostics can be done or hopefully by then, the issue has fixed itself.

 

[Sea-J]

Good advice, thanks.
If the weather changes and warms up in my area I'll go for a longer run at highway speeds and get the rust off the brakes while I'm at it Been a long winter.
Meanwhile if nothing works I'll just be looking for parking spots where I don't have to back up.