1985 240 Manual Transmission service

I have a 1985 240 DL w/ M46 Transmission (4 speed + od).

I am interested in draining out the fluid and cleaning any strainers
that the tranny might have.

Some questions:

1. Type F or G fluid is what my Volvo manuals call for, with synthetic
fluids as popular as they are today is it ok/better to use a synth oil
in this transmission? If so, what type should I use? Is there any
benefit/drawback to using synth oil as opposed to a Type F or G?

2. Are there any strainers in this transmission? If so, where are they
located and what is the best procedure for cleaning these?

3. Any additional tips that anyone might have when doing a
transmission service on this particular tranny?

Thank you for your suggestions and patience as I am a young Volvo
mechanic that still has lots to learn!!!

 

I filled mine with Redline MTL several years ago. It made a noticeable
improvement in shifting smoothness.

If I remember right, there's one under the pan on the bottom of the
overdrive unit, I washed it out with soap and water after removing it.

Nothing comes to mind, it's pretty straightforward so long as you have a
pump to get the new oil in. Remove the OD pan to drain the fluid from that.

 

To drain the transmission, you have to drain both the "regular" transmission
and the OD unit.
They share the same oil, but you need to open the drain plug on the trans,
and the pan/filter on the OD unit to get all oil out.

I remember I was told some years ago, to change from ATF oil to regular
syntetic engine oil, like the Mobil1 or similar. But someone here might
clear this out ?

Per Mathisen
Norway
-88 780

 

I would use the fluid recommended in the owners manual, or if Volvo
recommends changing to a synthetic then make the change.

Usually not needed. Are you having problems with the transmission?

 

I think Volvo dropped support for this gearbox long before the fancy
synthetic fluids were commonplace. At any rate, the synthetic made my
gearbox shift noticeably smoother.

Changing the oil is recommended on these, the overdrive unit is
essentially a 2 speed automatic transmission stuck on the back of the
manual gearbox so the same fluid change recommendations for automatics
apply here.