47RE shift problems

[BigPapa]

Bear with me, I know it’s long but I want you to get the whole story. Tranny has @ 40K miles on the rebuild, done by a good local builder with a Goerend constant pressure VB, Goerend TC, billet band anchor, and billet input.

Just before New Years my tranny started “flaring” the 1-2 shift. It would shift, then “flare” into a neutral/no pull, then gradually pull into 2nd. All other shifts were OK. Then, the next day it started doing this in 1-2 and 2-3. It really didn’t want to shift to 3rd. Temps never got over 170 and actually went down while it was doing all the slipping. Fluid was @ ½ quart low but was nice and red and smelled good. I called Dave and he said it sounded like the filter was possibly clogged, to change the filter and fluid and check the band adjustments. I took off to get some fluid and it got to where it wouldn’t hardly pull at all. It was actually worse with the convertor locked than unlocked. It pulled good from a stop and reverse felt good.

New Year’s Day I changed the filter and adjusted both bands. Both were out of adjustment. Since then it has done great, until today. It started “flaring” the 2-3 shift after getting up to operating temp, 150*. Fluid level, color, and smell is good. I let it cool down for @1 ½ hours and drove it again. It shifted great until I sat idling in line, in neutral, at DQ for 20 minutes. The temp warmed up to it’s normal 150 while waiting, and when I pulled off it didn’t want to shift to 2nd or 2-3. If I get up to speed in 2nd and REALLY feather the throttle, it will shift to 3rd and it’s good until I have to stop or slow down again.

Seems to be temp related. We’ll see what it does in the morning when I take the kids to school. What do y’all think?

 

[BigPapa]

Well, she did fine till the temp got up. Started flaring this morning @ 130-135*. Once in 3rd it was OK and downshifting from OD-3rd was OK. once in OD lockup worked OK also.

 

[LAmiller]

Fluid thins out as temps rise, if for instance, the second gear servo seal is leaking, it will tend to work correctly when the fluid is cold/thick and give you a solid 2nd gear engagement, then as it heats up and thins out the fluid pressure begins bleeding out of servo causing a premature band release on the 2-3 shift, giving you a flare. I would say you have pressure bleeding off somewhere causing your problem, I'd start with the 2nd gear servo since its accessible without dropping the trans.

 

[BigPapa]

Thanks for the help. I changed the solenoid, transducer, output shaft speed sensor (for an unrelated issue), and the filter. The fluid was nice and red and did not smell burnt at all. The magnet had the usual "fuzz" on it but nothing unusual or an excessive amount on it. All was good afterward. We'll see.

I changed the OSS sensor from a tip I read in another thread. Ever since I put this tranny in it has not wanted to do the first 1-2 shift after start-up. It wouldn't shift until I got to @ 20mph and it was harsh. once it made that first shift, it would shift fine until you turn the truck off and then it would do it again, but just that first shift. The new sensor fixed it.