Changed fluid and filter. Fluid was thicker than normal, black and burnt smell.Swapped F & R solenoids,no difference.I was able to get forward a few times by revving rpms after a few seconds it would go.Pulled valve control cover,removed F. R. and safety valve spools.Safety valve was stuck.Applied air at forward and reverse ports.Reverse clutch engaged but also bypassed a little air. The forward clutch appeared to engage but it was blowing a lot of air out of clutch pack.Tranny has 800 hours since last service.Total hours on lift 6,210.9 ! Help would be greatly apprecieated!