Hi I have a E30 BMW with a 1UZ and auto box but as soon as it heats up there are no gears can anyone give me some advice on what the problem can be.

 

Welcome to CL as a brand-new poster.

You mention that you lose the gears when the transmission gets warm. First, is this a conventional torque-converter auto-box with fluid, or a computer-controlled dual-clutch SMG/automanual? Second, does it function OK when cold or before the fluid fully warms up? Cooler fluid is generally thicker and more viscous than hot fluid and can more easily transmit torque. Perhaps, for some reason, the fluid is heating up too much...if so, it will transmit little if any torque. This will usually be more noticeable in the higher gears than in first/reverse or second, because the shorter gear-ratios in those speeds naturally multiply more power.

 

Just went through this with our '05 Accord V6. Honda has had many many problems with the V6 transmissions of late.
Symptoms were identical.
In our case the transmission was shot. Drain plug looked like a snowball with all the filings it picked up.
Get it to a shop & have the fluid & filter examined/changed. Tell tale filings will give you a general idea of what's happening inside.