36v EZGO power issues

[Thumper_abn]

I just got an 98 EZGO 36v electric. Not sure of the model. It seems to have an issue with hills. I've had to pull it in from the yard already and I've only had it 2 weeks.
Here's a little back story. I got it in a trade and it looked like I had a pretty good deal. The guy said the batteries were 2-3 yrs old. I checked them and it has 2 trojan 105s, and 4 low end deep cycles/cart batteries. I had to put 1.5 gallons into the 4 off brand batteries. I've spent 30-45 minutes cleaning out the charger(it sat in a barn with the cart). I've checked the voltage of the pack before chg and it was 36.7v. It reads 40.8v after the charger shuts off. Nothing seems hot or abnormal with the charging.
I've taken it out to where I hunt and rode around with the wife and kids. We had to tow it up the hill with a 4 wheeler to get out. It runs fine on the flat ground and slight inclines but any type of hill seems to kill it.
I re-wired the lights to a separate 12v auto battery and redid the switch for that hoping that may help.
Tonight we rode around the yard to check aiming of the lights. Got to the upper side of the yard and I stopped to let the wife and little girl get adjusted. It wouldn't start back up. I tried reverse, nothing. Back to forward and nothing. I went back and forth several times trying to get a response but it never moved. Had to push it into the garage.
Any ideas or advise?