G'day klancef51.
I think you may be reading that book of fairy tales again!!!!!!!!
If you have a Massey Ferguson 135 With a standard 6 or 8 speed transmission Listen to Dieseltech.
Split the tractor at the CLUTCH /GEARBOX ,drain the transmission oil, remove the clutch release bearing and fork and both shafts,remove four setscrews that hold the input housing in place mark the setscrew that has the copper washer under the head remove the housing ,remove the large circlip/retaining ring and knock the pto splined shaft on a piece of wood to separate,replace the input shaft seal ,then looking inside the pto drive gear there is the Transmission seal,Note before you remove it carefully measure the depth that it is set at so that you can install the new seal EXACTLY the same depth, Use a socket and extension bar as a tool to install the seal ,be careful ,make sure you start the seal square in the housing or you may be doing the job again ,should be able to do the job a lot quicker the second time around .
Happy days.
Hutch.
P.s. Refill with oil.
PPS.
I am not sure that Masseys made a 135 that only has Independent PTO WITHOUT Multipower!!!