The M47 manual gear box is NOT junk.

With care and proper gearbox lube, so long as the M47 is behind a normally aspirated engine with factory power output, M47 lasts.

With neglect, abuse, and lack of fluid checks (and top up) and regular fluid changes, your M47 will go crunch. Search or the article here using the brickboard search feature. Many articles and stories about M47. Turbobricks, like brickboard, includes articles about M47 rebuild. The parts are not so available.

Search for the article by vvpete here and on Turbobricks. vvpete is a member of both forums.

https://www.brickboard.com/RWD/index.htm?id=1537847

You can buy a new M47 II from Volvo for about 1200$+.

Ford "Type F" was a sort of misnomer for M47 gearbox. Yet the technical publications do indicate Ford "Type F." "Type F" fluid presents hydro static friction and it is about a 10W in motor oil viscosity. A slightly thinner then the GL-4 75W weight. The fluid type for M47 is a GL-4 oil. (Never GL-5).

You can use the Volvo lube they offer for M47.

There is the Redline (go to website) offering for M47.
https://www.redlineoil.com/mtl-75w80-gl-4-gear-oil

And Amsoil SuperShift
https://www.amsoil.com/p/super-shift-racing-transmission-fluid-sae-10w-art/

vvpete recommends the synthetic Volvo lube mentioned by Grey245.

NEVER Dexron, Mercon, or the like. M47 says no.

Also, as old as any Volvo with M47, seals fail. The M47 seal are paper thin and can leak.

THe seals inside M47, particularly the selector shaft rod, can fail rather drastically.

With failed shift assembly bushings as these are made of a compliant nylon from the factory. You can still get these bushing. In the performance after market, bronze bushings make for a concise shift. You'll get a little more vibration at the gear shift lever. And the gear shift lever is not a rest for your hand. Use only when changing gear.

https://www.stsmachininginc.com/products/m46-m47-bronze-shifter-bushings-240-740-volvo

The same STS bronze bushing set, yet 10$ more.

BNE https://www.bneshop.com/ doesnot make these bushings.

Finally, use the overfill method to fill the gearbox abovethe level of the fill plug. Read here.

Copy and paste URL:

https://www.brickboard.com/FAQ/700-900/TransmissionManual.htm






--
Beh.

go to this Website

https://ozvolvo.org/archive/

in the search box Type- Trans

download
TP30056-2-MANUAL_TRANSMISSIONS_M45_M46_PDF


THEN Type- M47 into the search box to get 2 more Green Books for the 700 series
TP30941-1 and TP30941-1 Supplement


Then for grins---peruse the Aussie ---Brickboard.

https://ozvolvo.org

Before I would condemn anything internal I'd have a look at where the shifter connects to the shift rod from the transmission under the car. - Dave

Your original 5 speed trans was a M47 and was not too good of a unit unless you changed the type F automatic trans. fluid twice a year or more often with lots of driving.Their junk.
I'm not sure what 4 speed with o/d they installed but what you describe is the stick shift arm coming out of the trans from a very large nut that secures that stick into the trans. that vibrated loose. It's a fine thread large nut. But first you need to place the stick in through both shifter forks inside the trans then carefully tighten the fine thread nut.

Hopefully, the trans they installed is a M45 or M46 trans both are quite robust and can take a good beatin'.

Duck

Your original 5 speed trans was a M47 and was not too good of a unit unless you changed the type F automatic trans. fluid twice a year or more often with lots of driving.Their junk.
I'm not sure what 4 speed with o/d they installed but what you describe is the stick shift arm coming out of the trans from a very large nut that secures that stick into the trans. that vibrated loose. It's a fine thread large nut. But first you need to place the stick in through both shifter forks inside the trans then carefully tighten the fine thread nut.

Hopefully, the trans they installed is a M45 or M46 trans both are quite robust and can take a good beatin'.

Duck