Mf 135 leaking transmission fluid through cotter pin at bottom of transmission.

There are probably cotter pins or similar locking devices on the bottom side holding them in place.

I cant give you an exact date but it is from the early 70s. That is when they were yellow. My educated guess on this is 1973. If you go to a Massey Ferguson dealer with your numbers they will gladly tell you what year it is exactly.

need spark plug gap and point gap for MF 135

I found this link about the points gap and plug gap.
"My I&T manual says .021 point gap and .025 plug gap."
There's a lot more information on the MF 135 on the web. Just do a search ' MF 135"; "massey ferguson 135 perkins gas engine point gap"

1971 and appears to be one of these models. Massey Ferguson Model MF-135, MF-150, MF-165, MF-175 and MF-180

Remove the ball joint stud from the lower control arm. Remove the axle nut and remove the axel from the hub. Pry axle out of the transmission. Use a suitable tool to pry or pull the seal out. Clean seal mating surface. Lube seal lip and instal seal in transmission. You may need to tap the seal in but there are times when you can install it by hand. Then install axle, tighten axle nut, and install ball joint back into control arm. And tighten. Don't forget to put cotter pin in and check the transmission fluid.

1) Install or connect the following:

• Lower control arm
• Control arm bolts and nuts
• Ball stud to the knuckle
• Ball stud castle nut, tighten the ball stud castle nut to 22 ft. lbs. (30 Nm), plus 135 degrees

Note: Do NOT loosen the ball stud nut in order to align the ball stud nut slots to the ball stud cotter pin hole. If necessary, tighten the ball stud castle nut in order to align the ball stud castle nut slot to the ball stud cotter pin hole. Ensure that the cotter pin ends do NOT contact the ABS wheel speed sensor, the ABS sensor connector or the drive axle.

• NEW cotter pin and bend the ends
• Stabilizer shaft link
• ABS wheel speed sensor jumper harness to the harness retainer clips
• ABS wheel speed sensor connector
  • Lower control arm nuts, tighten the lower control arm nuts to 71 ft. lbs. (96 Nm)
  • From Chevrolet web site.
    

1) Drain the transmission fluid.
2) Remove the cotter pin going through the axle on the front
of the hub nut with some need nose pliers. You may need to
remove the tire to get the cotter pin out. If so, jack up the car,
remove the tire. Take out the cotter pin, put the tire back on and
lower the car.
3) Loosen the hub nut, you will need I think a 32mm deep socket
thats a loaner tool at autozone. But it may not be a 32mm youll
have to figure that out yourself! You you can the socket and return
it and get your money back. Have someone step on the brake pedal.
Put the 32mm socket on the hub nut, attach a breaker bar to the socket
or a ratchet. Have someone step on the brake pedal for you. Then hit the
breaker bar or ratchet with a hammer, these nuts are really hard to remove
thats why im suggesting a hammer. You can also spray some wd-40 on the
nut and let it sit for a while. Then try to take it off.


4) Jack the front end of the car up and put it on some jackstands.
remove the tire.

5) Detach the nut holding on the tie rod end, it has a cotter pin you need to
remove too before you can remove the nut. After removing the nut hit the
tie rod end soildly with a hammer and it will pop out.

6) Remove the screws/nuts holding the ball joint to the lower control arm.
The fasteners are on the very bottom of the hub behind the brake rotor.
Pry the ball joint away from the lower control arm. Then you can pull the whole
hub/brake caliper and rotor away from the car. Then pull the end of the half shaft
from the hub. Then pry the other end of the axle from the transmission with a
crow bar or something similar, and you are done removing the axle. You have to pry
because there is a retaining ring holding the shaft in the transmission. Its a good idea
to replace that retaining ring on the axle. Be careful not to damage the seals where
the axle goes into the transmisson.

7) Reassembly is just doing all these steps in reverse order.

separate the ball joint and the tie rod from wheel unit and swing it out far enough to slip axle out of wheel, pry it out of trans and replace

Not the clutch... and maybe not the transmission internals...

Since you mentioned clutch, I assume you have a manual transmission and not an automatic transmission.

In a manual transmission, Reverse is the same gear as first gear, it just runs backwards...
... you may not have fourth gear ... sure?

It may be the linkage immediately on the outside of the transmission.
Look to see if any metal bars are "hsnging down from the bottom of the car. If so, re-connect them using a cotter pin.
Also, spray WD40 or Liquid Wrench on the linkage to loosen them up.

It may be the lube in the transmission. There is a plug on the side of the tranny. Open the plug and feel if there is lube inside. If not, then
find the plate on the side of the transmission and remove it (place a pan under it). Spray WD40 / Liquid Wrench to loosen the gears and levers in the tranny. Close it up and add lubricant (lube).

If by some chance, it is an automatic transmission:

1. Check the fluid level, just in case.
2. It may be the vacuum "modulator" ($20) or a leaking / disconnected vacuum hose anywhere under the hood or at the modulator on the side of the transmission.

Post more info if possible, or comment ...
Thanks..

you will still need add the proper type fluid to proper fill level, get under the truck, clean up transmission so you can visually monitor where the leak is coming from. Chock the wheels, emergency brake set, start and idle vehicle check for leaks. If trans is leaking it will probably be a front seal (oil will drip from small hole in the bottom of bell housing), pan gasket, loose cooling line to radiator, or rear tail shaft leak ( where drive shaft enters the trans.) Don't forget to check the lines for pin holes and the radiator for leaks.