Hi Boy Racer. This subject has been the topic of may threads in the past. You may care to try the search facility that you will find in the centre of the screen at the top of your post and have a read up. I'm sure they will give you the answers you want, but usually the RV manufacturer needs to supply you a new VIN plate and then depending on which State you are in, follow through on the various processes. Here in WA, it requires a new plate (and you are not allowed to remove/cover the old one) have it weighed and then then inspected by an authorized mechanic (easier) or put it over the Ministry of Transport pits - costs about $200. But some States are much "slacker" in upgrading your ATM

John (OBR) you already have the capacity to get an engineer to certify a heavier rating. Your van already has the 1600 kg axle under it that he is talking about. Did you take the van to him or just quiz him about what needs doing? If he eyeballed the van then he is just a spiv, go somewhere else for advice, preferably the engineer you are getting to issue the engineering certificate.

Our caravan VIN plate lists the Axle Group Load Capacity at 1600kg

That allows you GTM of up to 1600 kg and your ATM can be the expected loaded ball weight above that.

If you have a "Friendly" mechanical engineer sign a piece of paper signing compliance www.ebay.com.au/itm/Boat-Box-Trailer-Caravan-Horse-Float-VIN-Plate-Tyre-Chart-Placard-/332165776474

Pleased to advise I have finally managed to complete the process of an ATM upgrade on our caravan over here in West Australia .

Because our 2004 Avan - Erin VIN plate rated the axle group at 1600 Kg , it was relatively simple once I eventually found the right person to deal with . As advised by him at the Vehicle Inspection Centre , I had to do the following before it could be inspected for the ATM upgrade :-

1. Needed to get a new tare weight docket ( was up from original tare listed as 1185 Kg to 1340 Kg ) from the local registered weighbridge .

2. Had to have a plummer/gas fitter inspect the relevant components on van and obtain a new LP gas serviceability certificate & plate
( this was because our van & original certificate was more than 10 years old ) .

3. Purchase, fill out & install a new VIN plate adjacent to original , showing upgraded ATM and Tare figures etc .

4. Fill out a brake capacity form ( supplied at my first visit by the Vehicle Inspection Centre ) on which a list of questions had to be answered by me as to brake type, brake manufacturer, brake size, brake capacity ( the rating of 1600 Kg for brakes was provided by the Vehicle Inspection Centre from a listing he had ) , tyre size etc etc . I had to sign this form confirming all the information provided was correct .

5. Then make a booking at the Vehicle Inspection Centre for an inspection which also had to include a full roadworthy check of lights, chain size & condition, tow hitch rating, tyre load rating etc costing $97.00 . This figure seemed very reasonable considering the amount of time they spend providing information and then completing the required tasks .

6. I then had to take the supplied paperwork down to Dept. of Transport and have them upgrade their records for our caravan . It will now be slightly more expensive to license each year because of the weight increase , they don't miss you do they .

So I am now a "happy chappy" and hope this information may be of some assistance to other caravaners out there .

Cheers .......oleboyracer .