frightliner cascadia 2016

hiaibox

This sounds like a torque converter clutch (TCC) or transmission shudder issue on the Allison DD12 (or Detroit DD-series with a 12-speed automated manual). Here’s what’s likely going on:Most Common Causes1. Low or Contaminated Transmission FluidThe most common culprit. Check fluid level and condition — dark, burnt, or milky fluid means trouble.2. TCC Slip / Clutch Pack WearThe 9→10 shift is a critical lockup point. If the torque converter clutch is slipping or a clutch pack is worn, RPMs flare and you feel the jerk/jump.3. Adaptive Shift Data Needs ResetAutomated transmissions learn shift patterns. If something disrupted it, the ECU may be commanding the shift incorrectly. A dealer or technician can reset adaptive data with diagnostic software (DAVIE or Detroit Connect).4. Faulty Solenoid or Valve Body IssueA stuck or lazy shift solenoid on that range can cause delayed engagement, causing the RPM spike then lurch.5. Driveshaft / U-Joint SlopSometimes what feels like a transmission jump is actually driveline lash — worn u-joints or slip yoke can snap on engagement.Steps to Take 1. Pull fault codes first — connect to DAVIE or a shop with Detroit diagnostics 2. Check transmission fluid level and condition 3. Check for any active or pending TCM/ECM codes 4. Note exact conditions: loaded vs. unloaded, cold vs. warm, highway speedWhat to tell the shop: “RPM flare on 9-to-10 upshift with a driveline jolt — possible TCC slip or shift solenoid issue, need TCM fault codes pulled.”

john

I would start simple check ups, inspect transmission oil, also inspect your drive shaft u joints especially if truck vibrates

dhulfiqar971

it’s 940k the told me to not touch the transmission fluid

john

@dhulfiqar971 can you check if the oil level is good and the quality as well. There should be an access from under truck, right upper side of transmission.

dhulfiqar971

I’ll check thank u

john

not a bad idea to disconnect batters to reset.

dhulfiqar971

I’ll try this it’s automatic and I just uploaded a video it looks like same as video

jojo

is this truck a manual or automatic transmission?

dhulfiqar971

it’s automatic and I just uploaded a video it looks like same as video

owneroperatorlife

9th and 10th gear and you're only going 25 or 30 mph?  RPM jumps because the valve body is sticking during the shift, start with maintenance by changing the fluid, and probably need to get the valve body serviced and checked for sticky plungers or defective fluid control solenoidsHow many miles/Km on the vehicle/transmission? How many since the last fluid service? What vehicle, engine, transmission? Does this happen loaded or empty?