Do not use Jaguars with window motors

[yarden.saa]

My team arm is lifted with two window motors on the same shaft. Because my team is new (2 years) we had only Jags , but the motors had a strange noise when they work together and couldn't lift the arm often. To check the problem we tried the arm with just one window motor and it worked without problems but we wanted two motors because of the strenth, thank to our neighbours team 2630 we replaced the Jags with victors and it is now working.
Why it happend?
I think that the Jaguars are not giving a equal voltage or something so the motors are not in the same speed and opposing to each other.
Does someone have a clear explaination why it happened? because I heard on other teams that it happened to them.