Using hardware other then original is what I would like to do, But this are leased units and the customer want's to keep them 100% original. Everything electrical mounted in Jungheinrich units comes loose, nut's and bolts fall out, Compared to the competition I would say it's a design flaw they could easily fix.
Other then that there good units.
you can email me at: gunkbegone at yahoo dot com.

Does this seems to be the hardware used? If replace with different bolts nuts etc does the problem continue?

The #1 problem I have with these units and I'm talking about just the electric models is the way they fasten everything together.
Nut's, bolts, retainers and such no mater what you do, seem to fall out, come loose, strip what ever. wp4500 and nr4500
I have never had this much trouble with other brands and I have been doing this for 27 years.

Good to hear. I am soon relocating to Houston to join MCFA as a service engineer focusing on Jungheinrich product. Would love to hear more about failure issues, how customers receive the truck and so forth

We run a lot of Jungheinrich kit both in our rental fleet and customers own. Warehouse kit is the best on the market but can be hard to repair without the diagnostic equipment. We have some reach trucks that have done over 20000 hours and don't give any issues. Controllers can be very expensive as they are propriety items. AC hyd controller for a 3 wheeler is close to £3000GBP!!!! Torque converter IC trucks are good as they run Mitsi running gear but steer clear of hydrostatics they are electronic controlled, hard to repair and un reliable.