Customs OD going back together.

Several of you on the HAMB helped me diagnose my problem with my 1950 MERC overdrive. Thanks for that! Now that I have everything that was FUBAB out of the overdrive and I have a replacement planetary cage and sun gear, I am putting it back together. The old parts were so totaled and deformed that I had to carefully use a torch and a grinder to get them off the main shaft. See the pic of the destruction. Anyway, I have put in a new tailpiece bushing and everything else is ready to go back together. I have a question, the mercury manual gives instructions to check the resistance to slipping between the balk ring and the gear plate. The manual says to clamp the gear in a vice and with a spring scale, pull on the balk ring. The scale should read between 3 and 5 pounds when the ring is moving. Well, mine is not the much. It is not a loose fit, but it easily turns with minimum effort. Now for the question, is this resistance reading important? What happens to the overdrive performance when the ring is not as tight on the gear plate as it should be? If it is important, are there any fixes other than a replacement ring and gear?
Thanks

 

Yes, the resistance is important. It acts as a brake to slow down the sun gear so that the overdrive pawl can lock it to the case. It is sort of a synchronizer.

I haven't had an overdrive apart in ages. I don't remember if you can take it apart and "tighten" it up or not. I'm sure I would try.

 

Borg Warner Overdrive Service Manual (oldwillysforum.com) Page 15, paragraph 28. This states that 4-6 lbs is needed with NEW parts (close to your 3-5 lbs), it can go as low as 1 lb with 'thoroughly broken-in parts'. Below that, new parts are recommended. I'd also recommend checking the overrunning clutch rollers for wear, if worn too much it won't engage. There is a minimum allowable diameter for these that I recall seeing. You may have to hunt for the spec...

There are wearing parts in those that do need replacement sometimes.

 

After I wrote this post I read the OD service manual you quoted and saw the explanation of what the balk ring does so I know I can't just put it back in like it is. I also read in that service manual that you could squeeze the ring and reform it a little to make it tighter on the gear as an alternative to replacing the parts. Has anyone ever tried that? I think I'm leaning toward finding a suitable replacement balk ring/gear set but I don't think they are made as an aftermarket part so I'll have to look for a good used set.

 

If the fit between the ring and the balk gear is really loose, I’d suggest getting another set that’s tighter. The parts do wear. If it’s not too loose, you can compress the diameter of the ring slightly to create a tighter fit. It’s a bit of a trial and error process as you don’t want to make it too tight either. I place the ring (edgewise) on a block of wood….on the floor of the shop….and lightly bounce a 5 lb hammer on the opposite edge, then test fit it on the balk gear. If it’s too tight, spread it slightly in a vice and try again. Be sure to oil the groove of the balk gear for the test purpose.

 

There is no movement between the ring and gear, it's just that there is not any drag either, I'll try the hammer/ block of wood fix today and let you know..
Thanks

 

I should have finished out this post long ago but I forgot. I bent the balk ring with a hammer and got it to read in spec with 4.2 pounds of resistance. I re***embled the transmission and now the OD shifts as it should and when I floor the throttle it also downshifts as it should. Thanks to all for your help. I'm ready to go!

 

Everyone loves a happy ending!

jack vines

 

Thank you for posting the outcome! Certainly helps for thosecof us who may have the same issue in the future

 

I have am***ed a half dozen of those balk ring combinations for future use. That said, I've driven one of those overdrives, personally, for over 70k miles and the ring was still good resistance wise when I did a rebuild due to a faulty second gear. When rebuilding, I just chose the strongest resistance of the ones I have. I have read about squeezing closed for more resistance, sounds good to me.
Congratulations on the journey! I bought an overdrive off an auction site and the od was munched, had to use a cut off wheel to salvage what I could. BTW, not as bad as your picture! Great job!