Help finding gear ratios

I'm trying to find the gear ratios for my 5 spd main trans. I have the ratios for the 4 spd auxiliary box. The truck has 3:55 rears on 24.5 tall rubber, and judging by how it rolls down the road I would guess the 5 spot has a drive ratio of around .84ish. Number 4 in main seems like it may be direct drive 1.00 but I would like to find some kind of chart online so I have a better idea. Thanks for any input.

 

Yeah the main trans is a 5 speed PSO series. Can’t get the model number or Vin off the main box, that’s why I’m looking to find a chart on it. The auxiliary box is the AMO1750. Final drive on that is .81. That’s how I’m able to take an educated guess on the main. But it’s still a guess. They are the original boxes from 1986. I appreciate your help on tracking this down b/c the transmissions pre-date any dealer knowledge.
I wish they still made these today as an option for new trucks. It’s a very versatile set-up.

 

I see someone on here put the ratios up for the 6 speed version. I have a feeling this one is very close to that bc the 5 hole is a overdrive up to the dash, not the direct H pattern.

 

Rears are 3.55. Tire rotation is 472 per mile. Speedo is very accurate it’s satellite. I got the final driveline at .67ish. That’s with both boxes in big holes 5 & 4. But I’m having trouble with all the other gears in the main. That’s why I was hoping to just find a spicer chart. Overall it’s all good I’ve been using the 6&4 chart and it seems close enough.