Detroit DT12 shifting problems

My transmission has not rev up between shifts after I changed transmission oil and about 1500 miles. I made sure to buy the right spec oil for my year of transmission. Had dealer change the oil before and wonder if they used the newer spec oil which I don't think is backward compatible.

 

What oil did you use?

 

Update: Tranny was dropped again and metal filings were found inside. It is worth noting that this unit has 800,000 miles on it. A rebuild was put in from a Canadian firm. 2yr guarantee as opposed to Daimler Rebuilt with 1yr. I tracked the old unit as I had the serial number and got in contact with the rebuilder and asked if they would let me know what they found. The dealer didn't even advise or document the rebuilder. I had the wherewithal to ask.
They did say the split pin was in the casing. Fault the dealer repair. But the play in the input shaft was significant. They said the opening was oblong. The 3rd gear was gone. Replacing might be your consideration as dropping these units out for any service is costly. You don't want to be neck in it in 12 mo. I also replaced the TCU at the time. Around $20,000 in November 2023 and I'd spent $8-9k in Feb 2023

 

Delo Syn-AMT 75W90 for a 2016 DT12. Later models use a different spec.

 

Who was the re builder?
Thank you

 

ULT
ULT Powertrain: Your parts source!

 

That's what I thought. Thank you. If you don't mind it can you send me the pm and explain how the procedure sending the tranny to Canada and may I ask you how much is the full rebuild for the dt12.
Thank you for your time.

 

Sorry, I am not affiliated. Contact the Toronto (Mississauga) branch via the web page and they will respond and direct you. 2yr warranty (Detroit Reman - 1yr)