After overhaul on Cummins ISX CM 870

I picked up my semi with Cummins ISX CM 870 10 days ago from the shop after an overhaul was done

I wanted to ask several question about it.

This overhaul included : head, bearing , pistons , liners , oil pump , dumper , radiator and alternator.

The reason for this overhaul was due to an excessive oil consumption.

Prior to doing the overhaul ,my oil pressure was 38 at 1500, however after the overhaul my oil pressure went down to 32 . The shop used mobile oil . I use only Delo

Is it possible that my oil pressure went down from 38 to 32 because of the different oil or the shop did something to the motor ?

After I took the truck , I drove 1500 miles and the first problem that occurred was with the computer not be able to read the brake and I was not able to turn into gear( transmission done 7 months ago by the same shop)Second problem occurred the same day later when my truck shut off on the hwy while driving with 60 miles per hour. Later I found that the ignition fuse went bad. It was changed by another mechanic and as soon as 2 miles driving the same fuse went bad again . I managed to get back to the shop that this the overhaul, after changing 5 fuses within 40 miles and left the truck to the mechanic to fix all these issues. In the main time , I saw that their was a leak coming from the gear fuel pump and asked the mechanic to change both - the gear and the electric pimps since they were old. He did sent me a picture of the fuel two days after taking back my truck stating that the fuel was very dark (prior to the overhaul) and advised to change it next week.

Would you please provide your opinion on why the oil pressure went down after the overhaul and if the other problems that occurred may be related to the job done by the shop.

I did not have any of these problems prior to the overhaul.

Also I would like to know if you have to put money down prior to the overhaul as I was asked for money upfront before this mechanic started to work on my truck. I have been his client for 10 years and never before I was asked for money upfront.

 

How do I know if he used the OEM parts not aftermarket parts? He was paid to use original parts , however some of the parts that he used were RX parts... even thought he was told to use original parts

 

How do I know if he used the OEM parts not aftermarket parts? He was paid to use original parts , however some of the parts that he used were RX parts... even thought he was told to use original parts

 

Can you help me out to figure if he installed brand new cylinder head . I took picture of the head and the number stamped on the head is 4925774 . However my invoice from this shop reads 5413782.
When I did some research , I could not find any brand new heads with 4925774 but I was able to locate 5413782 as a brand new head.

 

Can you help me out to figure if he installed brand new cylinder head . I took picture of the head and the number stamped on the head is 4925774 . However my invoice from this shop reads 5413782.
When I did some research , I could not find any brand new heads with 4925774 but I was able to locate 5413782 as a brand new head