48V TD losing top end in forward, not reverse

[ccqccq]

Hi Folks-

I've been lurking here for quite a while and appreciate all of the expertise offered. It's finally time to ask a question.

I have an older 48v Taylor Dunn cart (B2-48 ) which I have been refurbishing as a project. It has generally run pretty well, but I have been chasing various problems for a while! I finally had the motor remanufactured as it became the source of intermittent problems (short/etc), and got it reinstalled (ugh) and the chain tension adjusted. I also replaced the solenoids last year as they were potentially another problem. My last major thing is to replace the batteries, which are maybe 6 years old but were not well taken care of (ran dry, etc). I haven't done that yet, and may try to avoid it for a while if possible as they seem to hold a charge decently enough.

The problem I'm having now is that the car is running perfectly in reverse, top speed, etc. But occasionally, not always, in forward, I seem to be lacking some torque and top end. Not a LOT (pretty sure it's not a half speed reverse hooked up backwards!), but definitely noticeable. Also, it seems as if it takes more throttle travel to get the car moving when going forward versus going backwards. I'm wondering if anyone has any suggestions?

Things I can think of that it might be:
--Bad forward solenoid even though it's new (there are three that work together on this model)
--Motor problem in only one direction (unlikely?)
--Forward/Reverse switch (unlikely - it provides just signal voltage to the Alltrax controller)
--Maybe just higher friction/wear somewhere in the drivetrain because the cart spends the vast majority of time going forward?
--Some strange battery or lead problem that only manifests itself only going forward?
--Something else entirely?

Anyways, I'd appreciate and insights or thoughts on the problem or ways to test to see where the problem might be.

Thanks again!!