48re 2-3 shift issues

Q

quadragin

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Aug 4, 2014
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I have the Transgo shift kit,
Sonnax 2nd gear hold kit and accumulator piston,
BW solenoid, new transducer,
new lockup/reverse solenoid.
so here is the issue, after installing all this the trans shifted great except it would seem to come out of 2nd then shift into 3rd, or at full throttle it would hold in 2nd then shift into 3rd.. Lockup is nice and solid
My new problem is that when the trans wants to shift into 3rd it feels like it falls out of 2nd motor revs. If I play with the throttle I can get it into 3rd, once in third its fine into 4th etc.

If I manually shift it sometime will shift into 3rd with no issues if I time it just right.

Would this be the Borg Warner Solenoid??
 
quadragin said:
I have the Transgo shift kit,
Sonnax 2nd gear hold kit and accumulator piston,
BW solenoid, new transducer,
new lockup/reverse solenoid.
so here is the issue, after installing all this the trans shifted great except it would seem to come out of 2nd then shift into 3rd, or at full throttle it would hold in 2nd then shift into 3rd.. Lockup is nice and solid
My new problem is that when the trans wants to shift into 3rd it feels like it falls out of 2nd motor revs. If I play with the throttle I can get it into 3rd, once in third its fine into 4th etc.

If I manually shift it sometime will shift into 3rd with no issues if I time it just right.

Would this be the Borg Warner Solenoid??
Click to expand...

Does it just rev for a second and then 3rd pics up? Or does it rev until you let off the throttle?
 
It shifting from 2nd to 3rd quick is based off of your PCM and throttle position more than anything.

And if it stays in 2nd and randomly goes to third, I had that happening when my solenoid was going bad. I could move it to neutral and back to drive to get it to move to the correct gear. But that doesn't sound exactly like what you described.
 
CorneliusRox said:
It shifting from 2nd to 3rd quick is based off of your PCM and throttle position more than anything.

And if it stays in 2nd and randomly goes to third, I had that happening when my solenoid was going bad. I could move it to neutral and back to drive to get it to move to the correct gear. But that doesn't sound exactly like what you described.
Click to expand...
No thats not my issue, NOW.
Now it does not want to shift into 3rd unless I play with the throttle
 
Have you tested the TPS? A lot of times they fail closed (0% throttle) and jump back to working, but they don't fail often in my experience.
 
These are the installed Sonnax Parts.
SONNAX BILLET ACCUMULATOR A727, A904 618, 47RH, 47RE, 48RE SONNAX 22841-04K
And
SONNAX Billet 2nd Super Servo Kit A727, 618, 47RH, 47RE, 48RE Sonnax 22301B-01K
And
Sonnax 47re 48re 3-4 Accumulator Spring 46re 46rh 47rh 42re 42rh Transmission

Trans-Go Shift Kit


Everything work OK after the Shift Kit and Sonnax Parts were installed for a few months until the 2nd gear slippage towards the shift point of going into 3rd gear

I have been laid up for a few months , Neck Spine Surgery, I went out and test drove her again to make sure of the symptoms
The truck goes into gear great R and D nice and solid

In D
1-2 shift firm
When she reaches the 2-3 shift point about 25 30 MPH she slips 2nd comes off and she don't want to go into 3rd. Playing with the throttle I get get a 2-3 shift but then it down shifts back to 2nd etc.. if I manually shift down to 2 and get the speed up to about 40MPH manually shift into D it will freewheel, if I let off throttle it will shift into third then it is good to go. with a nice firm 3-4 shift and lock up on.

Manually shifting
1-2 solid
2-3 I have to let off throttle wait for the bully dog to show 3rd gear then ease back on throttle then everything is fine 3-4 and lock up nice and firm.

Down shifting via throttle is fine and manually down shifting for engine breaking is fine.

If Direct Clutch was failing wouldn't all gears slip except OD?

Thanks in advance
 
I agree that it sounds like the direct clutch is slipping. Direct clutch is only responsible for third gear.
 
If direct is slipping, you'd potentially have slippage in reverse, 3rd, and 4th gear.

Overdrive engages a boost valve that increases line pressure so it's possible to slip in 3rd under heavy throttle but hold at moderate throttle in 3rd and any throttle amount in overdrive.

I would adjust the band and see how far it adjusts-in before getting snug to get an idea on band wear. I'd also drop the pan and look for abnormal clutch material build-up in the pan.
 
Mine does this sometimes, after recreating it a few times, I'm pretty sure it's a line pressure issue. Leaking past a seal somewhere when fluid gets too warm. On cold days I don't have an issue, on warmer days, it acts up after sitting at a stoplight or something for too long. Goes back to normal after a couple minutes of constant movement.

Have you noticed patterns of acting up during warmer ambient temperatures?
 
What band would I re-adjust according to the manual I downloaded 3rd gear has no band application.

Here is the manual I downloaded
http://www.brasilautomatico.com.br/downloads/48RE_br56.pdf

If I down shift into 3rd there is no slipping, and it will shift into 3rd if I am at about 40MPH but I have to let off the throttle wait for it to engage then reapply the throttle...

Mine seems to work better after warmed up, thinking about pulling Valve Body taking it apart cleaning and reassembling..
 
Last edited:
quadragin said:
What band would I re-adjust according to the manual I downloaded 3rd gear has no band application.

Here is the manual I downloaded
http://www.brasilautomatico.com.br/downloads/48RE_br56.pdf

If I down shift into 3rd there is no slipping, and it will shift into 3rd if I am at about 40MPH but I have to let off the throttle wait for it to engage then reapply the throttle...

Mine seems to work better after warmed up, thinking about pulling Valve Body taking it apart cleaning and reassembling..
Click to expand...


Down shifting into 3rd is just releasing OD(the direct clutches are already engaged), plus you are just picking up engine RPM.

I am still leaning towards the direct clutches slipping, as you say it slips until you let off.
 
I would try dropping the pan and checking for clutch materials accumulating in the pan. Then refill with a 50-75% mix of universal tractor fluid. ATF+4 is slippery compared to UTF and it's a $50 test to see if you have slipping problems because slippage will go down or possible be cured for a while with the UTF if it's a slipping 3rd gear direct clutch issue.
 
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