48re No lockup

[GuitarBrian]

48re No Overdrive (3rd gear lock up OK)

Hi all,
First post here... I am pulling my hair out with a problem.

I rebuilt my 48re over the last 2 days. Not a complete disassembly, but I replaced all the friction packs, and the 2nd/kickdown band. Which was the reason I pulled the transmission in the first place. The band was adjusted well past spec, so either wore out or stretched. Turns out it was stretched, plenty of friction material still remaining.

I had a slight 1-2-1-2 shifting problem, so I replaced the governor pressure sensor and the governor pressure solenoid, while I had the valve body off.

Put it all back together... took it for a test drive. Counted, 1,2,3,4 Lockup. All seemed good. It was late, so I parked it for the night.

Got up today, took it for a test drive, 1,2,3,4... no lockup. Got on the interstate, no lockup at the usual 55, nothing at 65, 75... Scratched my head, am I 100% sure it locked up last night? Well, no... since it was late and I wasn't able to drive very long at 60mph... only 5-10 seconds...

Got a pressure testing kit. Hooked it up. On the line pressure seeing 57psi in Drive... rising to about 90 in 3rd. Then jump to 140 psi in 4th(Overdrive). About 100-110 on the the governor pressure port. I think the first run was 1,2,3,4 BUT, on the second acceleration, I only got 1,2,3 Lockup. No overdrive. But, getting lockup now ?? I ran 2 more, confirmed the 1,2,3, LU.


Any ideas on where to start? I already did a switch wire to Pin "7" and at 60mph grounded it. No LU.

Replace TCC and Overdrive solenoids?

Did I put the oil pump gerotor in upside down? I looked at if for a long time, could not tell what side went up/down. Decided it was symmetrical. Now I read that the larger chamfer goes down... Man it looked exactly the same on both sides, but... I could be wrong... Would line pressure be wrong if it was upside down?

I don't have the right computer to check for codes, there aren't any engine codes on the dash. The Tow/Haul, and/or trans temp isn't coming on... Just getting lockup in 3rd, at about 3k rpm, I am just over 60mph.

ANy help would be appreciated.

 

[cerberusiam]

Did you ground it thru a resistor or straight to ground? Without the resistor it should immediately set a CEL. If you don't get a CEL and DTC circuit is bad or power is not being routed to the solenoids. Check pin #1 I think on the trans harness, the larger wire anyway. should have 12V when key is on.

 

[GuitarBrian]

Thanks for the reply. I don't have a CEL. I have been reading and doing more tests...

Took it out on the interstate, 76mph at 3k RPM... locked up.

But, with the pressure gauge on the overdrive clutch port, It jumps from 0 to 32psi... right where I expect it to shift to OD... about 40mph and a little lower under lighter throttle/deceleration.

The book says 78 to 140psi depending on throttle. So I have low pressure to the clutch... Signal is there, solenoid is shifting? But not enough pressure to engage? Or something else??...

It also seems that the TC is looking up at about the same point as before, 55mph under medium throttle. It stays locked up, doesn't pop out erratically.

 

[GuitarBrian]

I am planning on replacing the OD and TCC solenoids and wiring harness tomorrow. I am pulling the VB and doing a through cleaning and then reinstalling. Then test. If it doesn't change the OD clutch PSI... what would be next? Clutch seals? I just replaced them, it was a bit difficult to reinstall the clutch, had to work the seals back in, but I don't think it is leaking excessively.

Every time the OD should engage, I see 30-35 psi at the clutch port.

I am thinking sticky valve or OD solenoid.

Am I missing something? Should I be doing something else before the VB???

 

[cerberusiam]

Sounds like the OD clutch pack has gone south, that is not enough pressure. If the pressure jumps the solenoid should be working, not sure there is anything in the VB that would cause pressure to bleed off the circuit.

 

[GuitarBrian]

Pulled the VB, I forgot to tighten the bolts that hold the 3-4 accumulator cover on. One had fallen out, another was almost out, and the 2 remaining were about finger tight.

Put back in. 1,2,3,4 LU. perfect. Got on the interstate. 70mph@2000rpm. Perfect.

I am a happy man

Thanks for your help and ideas cerberusiam.