Overdrive Installation

[december2021]

I picked up a used overdrive unit to install in my 1977 MGB. The gears look excellent in the gearbox and the gearbox turns smooth through the gear patterns when I turn the input shaft. I will change the front and rear main seals plus O/D filter. There is a cover plate missing from the O/D unit and what I think is from MOSS parts catalog the coil assembly. I’m not sure if its stuck up in there from the pictures or all missing? If stuck how would you remove it? See pictures

Please fill me in on what you know. I can make the cover plate out of aluminum from a new gasket used as a pattern. Throw in any other suggestions.

Oh, is this a drop in replacement for my old 4 spd?

Regards
Fred Mauro
Bethlehem, Pennsylvania

[JohnTwist]

You’ll want to purchase a new solenoid assembly.  It’s available from Moss #80 on page 41 – 466-375.  Remove the remainder of the solenoid assembly with a pair of needle nose or duck bill pliers.  The piece you’re trying to remove looks like a top hat and you’re looking at the bottom of it. 

I’d clean out the overdrive and replace the O rings right now while it’s out. 
Oh – if it’s a top fill gearbox, then it’s probably set up for 1280 turns per mile on the speedo cable; if it’s a side fill gearbox, then it’s probably set up for 1000 turns per mile.  You want the later, 1000 tpm for your car, or the speedo will read 25% fast.
Except for the wiring, it’s a straight drop in.  Make CERTAIN you check the 4th gear switch about 20 times.  After installation it’s the least accessible electrical component in the vehicle.  It’s at the right front of the top of the remote control assembly.

Hope this helps.

SAFETY FAST!
John H Twist
University Motors Online
Cell:  616 307 6737
www.universitymotorsltd.com