48RE Odd First Gear Behavior?

[monkeh]

Trucks come back from the trans shop - With a "Don't come back."

We butted heads over what was "wrong" with the truck sticking in lockup.

After a rebuild on 3rd and reverse gear friction material and a new TC, He told me there is an odd 1st gear issue; he won't address it.

His thoughts, "With the truck sticking in lockup," was not the TC.

Anyway, the issue is 1st gear, when in Drive, will set off like it's slipping, almost like it's in 2nd gear as well as 1st.

However, if you put it into 1, it will usually pull off.

After setting off, it goes through the gears as usual, moving it into 2/D.

I can lay into the throttle, and it will be perfect when the shifter is down.

Transmission has had new clutches, TC, solenoid packs, and adjusted bands.

However, the VB is in stock.

I guess there may be a valve in the VB sticking.

As the sticking lockup isn't happening, another odd problem is occurring.

Any pointers?

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[sootmaster]

Get a second opinion on the fault; you need to test with a tester and PIDs on shaft speeds.

If you think it's SLIPPING, DO NOT DRIVE!

Only 20 seconds or less, you toast the clutches to the fault area or clutch pack.

Do all testing with the wheel off the ground and not weight on the truck.

I suspect that since recent apart and together and NEW concerns, some were tech errors or cut seals.

While VBs do fault with new concerns and the old one disappeared, I suspect internal hydraulic leakage OR cross leak in case of VB or cut pump sealing ring, or who knows till re-tear down to a fault.

Testing PID pressure without driving will see if you can drive, but since your concern is felt and slipped, it may already be toasted.

Without Tapping into pressure hydraulic ports and seeing actual pressures to ECU and data from the scanner on shaft speeds, there is no way to advise.

Trans-sensors are like wheel speed sensors that register rpm very accurately so they can see when slipping or when there are incorrect ratios.

Tow new shop for diag.

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