Gearbox BW65/BW35

ROVER827

New Member
My P6 gearbox (BW65) has to be repaired now. Last year, I only had 1st and 3rd gear and now
the reverse position is out of order, my car refuses to move back.
I have a second hand BW 35 from an earlier P6 I dismantled 20 years ago and I don't know
if it is a good idea and easy to swap my 65 for a 35...
Has any body done this before or has Harvey spoken about this already ?
jb
 
Going from a 65 to a 35 is easier than the other way around, but it's a retrograde step. The used 35 is an unknown quantity.

The two faults you have sound like servo problems, and they can be resealed without removing the box. If its the bands themselves then the box has to come out.
 
Thank you Harvey for your quick reply. I know it is a retrograde step and maybe not a very good idea to do this.

What do you mean by "Servo problem" ? Can I see something or check sth if I remove the sump ?

Many thanks again for your help ! jb
 
The servos are accessible after removing the covers on the outside of the box. One each side, retained by 4 bolts each IIRC. Then the pistons will pull ot, revealing the seals, which hopefully will have failed. You could drain the fluid to see what comes out before you start.
 
You are very helpful Harvey, thank you very much. I will have a look asap at these parts
and will let you know what I will have found out.
 
If it were me, as you've lost those gears already, I'd dismantle and see what you find. If you find that it is the servo seals, order those with the gaskets, fit and test. If it's the bands themselves then the box has to come out, so order your parts then.
 
Would it be possible that the cause of the problem comes from a wrong type
of oil ? I used ATF Universal, Dexron III, Ford MERCON oil....
 
Any fluid other than M2C-33F/G will cause the box to run permanently hot, and that could possibly cause premature seal failure, it will certainly reduce the lifespan of the friction materials.
 
Thank you everybody. I know what I have to do now..












I also added about 1 litre of same oil in my second Rover P6 that has been stored for 30 years.
The gearbox works very well now (I only made 30 kilometers...) but I know what I have to do now.
I will drain the box and put some ATF 33 in it before it is too late.
 
If it's full of an incorrect fluid, you will need to do at least 4 drain/refills with use in between to change most of the fluid because you can't drain the converter.
 
Hard job, but if it can save my 2nd gearbox, I will do it....
I have to find the correct oil now.
Thank you very much.
jb
 
Back
Top