Engine/Transmission (1998.5 - 2002) 47RE shifting problems

[Dt92]

This is my first post on this sight, so here it goes....

yesterday driving on my way to town, my truck was driving and shifting fine. I Shut the truck down and went about my way. When I got back in a few hours later pulling out of the parking lot I noticed that my truck didn't want to shift out of 1st. No mater how high the rpms went it wouldn't shift. Letting off on the throttle I could get it to shift but after shifting, it went through every other gear just fine and the tc locked up just fine. After passing the normal shifting rpm the truck seems to louse power and feels like it's slipping. I took the truck to my mechanic and he hooked his obd2 scanner up and was able to watch my peramaters. I didn't have any crazy codes, but my throttle position sensor was bouncing around between 37 and 48 at IDLE. the scanner was saying my truck was telling it that it was in second gear before it actually shifted when I was moving. I was told that there was static and I needed to re rout the ground wire running on my altanator, and that it could be causing the problem, I know this can cause some problems by causing interference but I had no luck. Fluid level is good and not burnt at all. I am at a loss, any help would be very appreciated! Thanks in advance

 

[Dt92]

Has no one else has this issue and found out what was wrong ??? After doing a lot of reading I have seen a lot of people with similar problems but thing along the lines of a fix or a check list on possible causes. I tryed shifting in to neutral and back to drive after take off when it should shift to second and after it goes back in drive it goes to second gear. Anyone have any ideas ? Any help would be awsome

 

[Joe Mc]

Hate to be a stick in the mud and sorry about your trans shifting problems, but... If you include your truck info folks can have a better idea on how to help, different years and etc. make a big difference. Noticing the above is your 2nd post and you might not yet know where to go to create a signature that will be included at the bottom of each post, just type in the truck info in your next reply for now.

That said, any troubles I've had with shifting, or not wanting to, were related to the transducer or solenoid attached to the valve body. Seems they tend to fail (at least for me) every 3-4 years, even though I purchase high quality replacements. Hang in there someone more knowledgeable than myself will jump in and once they have more info they'll be able to help more.

Oh, Welcome to the TDR!

 

[Dt92]

Thank you for the reply, I believe my sig will pop up now ??still trying to figure the sight out. the truck is a 2001 with a auto 47RE, mostly stock transmission. When I got the truck the transmission had just been rebuilt and came with paperwork but I still have no idea what parts were used. From what I could tell the only "upgrade" was a shift kit if that's even considered a upgrade. After I started to add power I eventually lost my torque converter. This time I have went about 8 months without any problems till this transmission issue. I was hoping to get some other advice on things I could check starting from the cheapest up. I would like to not drop the pan till that's the last option. The only thing my mechanic was able to tell me was that he was watching my TPS sensor (voltage????) go from 37 to 48. And told me that at idle it should not move. Also on his scanner he was watching trends and told me that before my truck ever shifted in to second during the "slipping" his reader was saying it was in second so I'm assuming the truck did think it was in second ?I do have a spare TPS if that really does need to be changed. Fluid level is good and also not burnt. I have seen too many people go straight to dropping the pan and changing the expensive pressure governor and or the solenoid both, and that not be the issue at all. Sorry for the long winded msg but I'm at a loss on that to start to look at I'm by no means a transmission guy and would like to stay as far away as I can from any auto, when this one goes I'm doing a manual swap but I need this one to last as long as it can.

 

[Dt92]

Any possible way I could need a new alternater ???

 

[Dt92]

Also figured out that if the truck is in 4 low it goes through the gears just fine if that help to get info

 

[cerberusiam]

There is no way the TCM can tell if the trans is an gear in auto mode, no sensor for that, the only way it thinks it is in 2nd gear is wheel speed compared to gov pressure and that doesn't make any difference if the gov pressure is wrong. First thing to do if you have no info on maintenance on the trans is replace the transducer and the output shaft speed sensor, gov solenoid since you have it open also and then you know it is done. Those are 3 WORST pieces in these transmissions and their MTBF is all over the board. If you can shut the truck off and make it work right, or, shutting the truck off makes it go bad it is an electronic issue and those are the heart of 99% of the problems. Try that first and see if anything changes before digging deeper.

 

[samsonite01]

I would try unplugging batteries for awhile. Hit the brakes before hooking them back up. Reset the tps. While batts are unplugged clean out the plugs on the side of trans and the speed sensor plug near the back. They may have got some gunk in them when the trans was takin out or moisture can get in there also. They make a cleaning spray for the connectors. Just make shure you blow it out when using it. Before re connecting put a bit of dielectrcal grease in the connecter. Also check the voltage in both batteries separately while there unplugged. They sould read close to the same.

If that dosent fix it try replacing the vehicle speed sensor.

Also its a good idea to periodically clean all the grounds.

These are simple things to start with before pulling things apart.

 

[Dt92]

I figured out today that in 4 low it goes through all the gears just fine, I was told by a friend it could be the transducer?? I already tryed unplugging the battery's for several hours and that didn't help sense it works fine in 4 low I'm assuming it is electrical? And could be the transducer??

 

[cerberusiam]

Problems with the transducer and gov pressure are covered up by the low final ratio in 4 lo.

 

[Dt92]

Shutting the truck off does nothing, I did try unplugging the battery for 5 hours and that didn't help ether. What do you mean 4 low covers up the problem ? Does that mean that is my problem ? And the transmission haven't been out for at least 8 months or so if not longer also could low battery voltage be the problem if that's somthing I need to check ? I'm sorry about all the questions I just want to make sure I cover all all my bases

 

[cerberusiam]

The ratio is so low that there is really no need to look at wheel speed to generate a shifting algorithm and abide by it. At times you are in D well before even the 1-2 shift happens in high range. Not sure on that truck if the PCM recognizes 4 lo and goes to a default shift algorithm like others but it may. The transducer is usually the root of the problem because it does not read gov pressure correctly and report it to the TCM correctly to allow the algorithm to work. When it bounces around shifting suffers.

 

[samsonite01]

If one bat is dead it will cause problems. Clean the connecters and make shure none of them got damaged taking the trans in and out. These are the simple things to check first. There are shifting problems caused by computer electrical interference. The altenator can leak stray ac voltage into the system if the diodes are bad. Do a search on how to test for it, there are some write ups on it. Our trucks have a low voltage interface that controls engine/powertrain/transmission managment. If the grounds start losing connection you can experience wierd problems. Clean the grounds, i do this once a year as regular maintenance. Do a search, there are good write ups on it. There are grounds everywhere. These are the easy things you asked for to check first.

If...none of these things work...

Drop the pan replace transducer and gov pressure. AND speed sensor. I like the GM conversion. You need them anyway. Can buy them in package deals.

Honestly you need more trans upgrades to run that thing with 200hp stikcks and a tunner. What turbo are you running? Did you upgrade to a billet flex plate and input shaft when replacing torque converter? Band, strut, anchor? Upgraded valve body? Who did the work on the trans?

You pay to play! I built my trans before any power upgrades. Mabey good idea to put a couple thousand more before you smoke tha new tripple disc.

 

[Dt92]

Thank you for the information !!! I know what I will be doing this next weekend. As far as the transmission goes I have had this set up for a year now and I am not easy in it. so if my transmission has stock internals I have no idea how it has held up this long.

 

[Cummins Thunder]

If one bat is dead it will cause problems. Clean the connecters and make shure none of them got damaged taking the trans in and out. These are the simple things to check first. There are shifting problems caused by computer electrical interference. The altenator can leak stray ac voltage into the system if the diodes are bad. Do a search on how to test for it, there are some write ups on it. Our trucks have a low voltage interface that controls engine/powertrain/transmission managment. If the grounds start losing connection you can experience wierd problems. Clean the grounds, i do this once a year as regular maintenance. Do a search, there are good write ups on it. There are grounds everywhere. These are the easy things you asked for to check first.

If...none of these things work...

Drop the pan replace transducer and gov pressure. AND speed sensor. I like the GM conversion. You need them anyway. Can buy them in package deals.

Honestly you need more trans upgrades to run that thing with 200hp stikcks and a tunner. What turbo are you running? Did you upgrade to a billet flex plate and input shaft when replacing torque converter? Band, strut, anchor? Upgraded valve body? Who did the work on the trans?

You pay to play! I built my trans before any power upgrades. Mabey good idea to put a couple thousand more before you smoke tha new tripple disc.

I second the above.

Gov. solenoid seems to be the immediate issue. You want this- https://www.dnjcomponents.com/products/d-cf1

 

[IdahoJim]

When's the last time the APPS was replaced? I have a buddy who's truck was acting just like this, and I found out he'd never replaced the throttle position sensor. I replaced it, and the truck ran like new.
Jim

 

[Dt92]

Update
still not fixed but after a little more driving I can now tell that it is shifting in to second I can feel it slightly but it's not grabbing if I put it in neutral and backingear it grabs fine. Still possibly the transducer?

 

[samsonite01]

Yup. Check your shift linkage out side the trans. Either that or accum spring and piston. Those activate the band that grabs the drum activating the shift. Band could be burnt up. Pump could be shot. Drop the pan. A few small aluminium shavings is normal. A large amount in the pan and clogging the filter means new trans. A metallic look to the fluid is a bad sighn also.

 

[DVolk]

It might need a filter change , i just learned these transmissions have a screen and a internal spin on filter

 

[Dt92]

Still can't figure it out, changed the TPS and speed output sensor and still not working. 2 times now I have also had it pop out of reverse, backing up slow it would just quit moving till I put in neutral and then back in to reverse, any ideas anyone??!! *I also have no idea what to look for in shift linkage or how to adjust that, of that could be the culprit? But the reverse thing never happend until the 2ed gear shifting problem but it's definitely still not grabbing in 2ed gear, it's for sure shifting but not grabbing. Also I have noticed that when I'm in 3ed if I excelerate any harder then Normal it goes right in to second and slips, it never used to do this. So still lost*