Sluggish trying to climb hills in 1st gear wot. Can only go down the road in 2nd and occasionally 3rd. Failed the pressure test miserably. Found the oil tube not placed in the oiler properly. Reassembled and pressure tests were in specs, but it’s still struggling. The internal clutch parts, pump and TQ appeared (visually)to be in good condition. Anyone have any ideas? Strong shift in forward and reverse, no delay. I’ll do a stall test and check to see if the tires have ballast in them today.
I take it you split her and examined the pump and clutch pack. Did you find any cracked sealing rings around the input shaft and/or did you crack any on reassembly. If you had low pressure and didn't damage the clutch pack, then you may have a T/C problem. You would need to know if you have a low or high stall converter. If a high stall, your shuttle may be operating normally. Stall her against a pile of dirt and see if she moves dirt in 1st gear. 1st gear is absolutely positively painfully slow so if 2nd 3rd and 4th get you moving 20mph+- down the road, that's all you're going to get. The 555, A & B weren't built with a road gear. Life was a slower pace in the 70-s and 80-s.
how long have you had this unit? my 555D was sluggish and seemed to have the same symptoms of you. it was fairly new to me, So I replaced my trans filter and fluid. now it works great. my guess is the previous owner put the wrong type in and it was causing the clutch slip. Maybe the same issue for you? or I at least hope so.. that would make it an easy and cheap fix