I own a 2003 GMC Envoy XL with the 5.3 V8 Last week it shifted REAL hard one time and stuck in second gear. but if you leave it sit awhile it goes back to normal, shifts fine until BANG does it again a few miles later, Sometimes its doing it from start up. I did a OBD 2 test and its pulling theses codes.....P1860, P0785, P0753, and P0740 I caught MAY03LT video on youtube and its got me thinking now before pulling the tranny pan !! Can anyone help me with this ? Thank you !!
Transmission Help
- Thread starter kronkus
- Start date
gmcman
Member
- Dec 12, 2011
- 4,656
How many miles does the tranny have? What is the service history of the trans?
Did you by chance flush it with high mileage?
My experience with these transmissions is they can last a very long time. What tends to doom them is infrequent fluid changes and pressure loss caused by a accumulator piston or worn separator plate...not just limiting symptoms to these two scenarios.
If the transmission is not slipping or flaring during shifts, I would check the wiring harness that connects to the trans, make sure nothing is broken.
If that checks out, and your fluid level is fine....check on level surface, trans hot, engine idling, I would then remove the pan and take a look.
My trans developed a 2-3 flare at about 165K miles, a check ball hammered it's way through the separator plate and I caught it early enough to avoid clutch damage.
I would check the filter, see what's laying in the pan. If you find some light silver residue that's somewhat normal if the pan hasn't been removed in awhile.
If the filter looks clogged, try a new filter and see what happens. If the filter pulls out with good resistance, and goes back in with resistance, then I wouldn't worry about the filter seal at this time. You can change it, but it's a slight pita but not that bad.
If you have over 150K miles, I would absolutely replace the separator plate. Get the plate from the dealer, it will be matched to the VIN and setup for your application....also, the new plates have the small filters in the plate as well as the gasket molded to the plate...much easier to replace when all in one.
If you did a flush on high mileage, then it sounds like you may have some material in some of your solenoids and/or valve body.
Hard to say without knowing more. I changed my separator plate, both shift solenoids, a couple of the accumulator pistons, and added the vette servo at about 165K, now it has 289K and the trans is still going....just my motor has an issue right now..lol.
Let us know.
Did you by chance flush it with high mileage?
My experience with these transmissions is they can last a very long time. What tends to doom them is infrequent fluid changes and pressure loss caused by a accumulator piston or worn separator plate...not just limiting symptoms to these two scenarios.
If the transmission is not slipping or flaring during shifts, I would check the wiring harness that connects to the trans, make sure nothing is broken.
If that checks out, and your fluid level is fine....check on level surface, trans hot, engine idling, I would then remove the pan and take a look.
My trans developed a 2-3 flare at about 165K miles, a check ball hammered it's way through the separator plate and I caught it early enough to avoid clutch damage.
I would check the filter, see what's laying in the pan. If you find some light silver residue that's somewhat normal if the pan hasn't been removed in awhile.
If the filter looks clogged, try a new filter and see what happens. If the filter pulls out with good resistance, and goes back in with resistance, then I wouldn't worry about the filter seal at this time. You can change it, but it's a slight pita but not that bad.
If you have over 150K miles, I would absolutely replace the separator plate. Get the plate from the dealer, it will be matched to the VIN and setup for your application....also, the new plates have the small filters in the plate as well as the gasket molded to the plate...much easier to replace when all in one.
If you did a flush on high mileage, then it sounds like you may have some material in some of your solenoids and/or valve body.
Hard to say without knowing more. I changed my separator plate, both shift solenoids, a couple of the accumulator pistons, and added the vette servo at about 165K, now it has 289K and the trans is still going....just my motor has an issue right now..lol.
Let us know.
gmcman
Member
- Dec 12, 2011
- 4,656
The video you saw I assume it was him talking about fuse #47? If so, let us know if the fuse is good. If the fuse is good, then take a look at the harness going into the trans and see if it looks like it has been disconnected and or contaminated.
If that checks out then you could test an ignition switch but I would look at the harness into the trans first.
I would also try to refrain from driving it mainly to avoid possibly a hard engagement which could possibly damage the sunshell rendering an unfortunate rebuild.
I'm assuming you checked the fuse since you watched the video...keep us posted.
If that checks out then you could test an ignition switch but I would look at the harness into the trans first.
I would also try to refrain from driving it mainly to avoid possibly a hard engagement which could possibly damage the sunshell rendering an unfortunate rebuild.
I'm assuming you checked the fuse since you watched the video...keep us posted.
Mooseman
Moderator
I would definitely look into those codes before opening it. We have lots of threads on this:
Transmission with multiple codes
Another Transmission with Multiple codes
More Multiple Codes
Transmission with multiple codes
Another Transmission with Multiple codes
More Multiple Codes
Update......
Ended up being the Ignition Module little box in the steering column, A $20 dollar part that caused all that heartache and time. It actually went out before in the winter of 2017 but i bought a cheaper one from Advanced Auto and it cause this problem. Actually bought a Dorman this time and all is good now !!
Ended up being the Ignition Module little box in the steering column, A $20 dollar part that caused all that heartache and time. It actually went out before in the winter of 2017 but i bought a cheaper one from Advanced Auto and it cause this problem. Actually bought a Dorman this time and all is good now !!