is my tranny done???

[fobrnno]

have a 2002 exp. with a 4.0l all forward gears work good no slipping with gear change. its just reverse if i apply too muh gas i get slippage and the o/d light will come on some time. what problem am i look at here worn clutches, bands or solenoid.

thanks for any input.

 

[PopRichie77]

Get the code read, Code has to be pulled with an OBD2 reader that can read transmission DTC codes.

 

[fobrnno]

while backing up a slight incline the rev gear started to slip and o/d flashed as i gave it more fuel to get up the hill.
the codes i recovered is P0720 and P0722.
all forward gears engage good no slipping. its just reverse that is giving me problems.

thanks

 

[PopRichie77]

Both codes refer to the output shaft speed sensor, It may have a bad connection at the plug or it is bad. However it doesn't seem likely it would be causing reverse to slip. Strange that there was no code referring to reverse. You should not backup and make reverse slip as it could burn out the clutch or the reverse band and cause more damage. The sensor problem needs to be fixed. The reverse problem could be a bad reverse servo pistion or the seals, bad reverse band also could be the solenoid block or a bad valve body gasket.

 

[Yankee516]

Good morning... sorry to hear about your woes. There could be multiple causes of the issue. I have rebuild my A4LD before, and believe that you have the next gen 4R or 5R transmission. The reverse band has no adjustment, and is actuated by a servo in the valve body. First thing to check is the manual linkage to ensure that the gear shift is adjusted properly. If it is out of sync, the transmission isn't diverting the pressure right to engage the gear. There are plenty of writeups on the proper adjustment.

If that isn't the problem, I would drop the pan and inspect the valve body to see if the separator plate and gasket appear to have leaks, the bolts are torqued to spec, and check if the cover of the reverse servo gasket is leaking. Might be as easy as replacing the gaskets, filter and re-tightening the valve body and servo cover to spec. See if you can get the atsg manual for the transmission to refer to. Depending on your mileage, you might want to also do a valve body rebuild too to ensure that all the valves move freely and remove the reverse servo piston to inspect for a leak in the seals and make sure that the piston isn't damaged and that the apply pin isn't worn. It needs enough movement to fully engage the band.

If none of the above work, then it could be a worn band or clutch, which would require a rebuild unfortunately. Hopefully some other members will pitch in their advise too.

Please let us know what you end up doing and good luck!!!

 

[fobrnno]

while i drop the pan and found the low /rev band broken and worn. so i removed the tranny and replace all three bands and all of the clutches and steel but it back and it as good as new again. should be good for another 280,000km lol thanks for the help.

 

[Yankee516]

Thanks for the follow-up! Sorry to hear about the reverse band, thought those bad boys were pretty solid! Glad your ride is back up and running!