Hmmm, yeah the car ride sounds promising…. so I wouldn’t give up just yet. Did you do pre-bonding? I agree that it sounds like you just need a better space. Could you try parking your car in the shade and doing sessions there without driving around?
Be very certain they cannot access each other when you are not doing a bonding session (such as through fence bars), as bad feelings can build up.
A friend’s house could also work. The shelter may also let you bring them both back to do some dates there. I did this for the first several dates with my two, as I have a tiny apartment with very little neutral space.
You could also try to “disguise” an area in your home by laying down a blanket or tarp they have never seen, with a pen around it, with the view blocked by more blankets, so they don’t know where they are. You can pop them in their carriers or a box and carry them around outside before putting them in the pen.
Some people also have success with a laundry basket on top of the washing machine while it’s running.
I would keep up the car rides if that is working, and then try to think along those same lines. It kind of sounds like you are just moving a little fast. My first pair took three months to bond, and it didn’t go in slow steady increments. it felt like nothing what happening, and then we would make a big jump forward. Then nothing. Then big jump.
Also, not sure how you are doing your car rides, but if they fight as soon as you bring them in the house, be sure to separate them before bringing them in, so you end the date on a good note.
The progression that usually works (in cases where stressing is helpful):
-start in very neutral, stressful space (so, the car ride, in this case).
-then start a date in a stressful space, and move them to an equally neutral, but less stressful space.
-then start the date in the neutral space, and move them to a stressful, less neutral space (so maybe the bathroom, with you vacuuming around them)
-then start a date in a stressful semi-neutral space, and reduce the stress in that same space.
– etc.
Work up to longer and longer sessions for each step. And before you progress, you want to see lots of positive behaviors (snuggling and grooming) and no fighting. Everytime you move to a less-neutral space, you might take a step backward, so you may need to make sessions shorter so that you can always end on a good note. It’s very important to end the date before they start fighting, as this is all really about building trust.
.
.
.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.