Transmission Trouble in a 3 Speed Overdrive

[Hot Rod Reverend]

Looks like I have synchro trouble fellas. The 55 has a mid-fifties 3 speed R10OD that I rebuilt (that really may be the issue here ). When I took it all apart it was pretty clean in the case with no visible signs of wear. There a lot of photos on my build thread and even more on www.hotrodreverend.com. Anyway, the transmission has been shifting fine, the OD working normal, until today. The shifter wants to now pop out of second gear when I let off the gas while either the OD is engaged or not, makes no difference. Obviously this is more noticeable if the OD cable is pulled out. Once she pops out of gear, even if I let her coast with the clutch pedal pressed and try to shift back into second I hear and feel some grinding.

Is this a synchronizer issue? I did use TSC mineral oil for the gearbox so as not to use an oil that would eat brass. Is there a possibility something else is going on?

One thing, if I hold the gear shift in second there are no problems. Shifting UP through the gears all the way to third are not an issue either, smooth as silk. When downshifting from 3rd to 2nd normally, I do get some grinding on occasion. Has to be a synchronizer right?

What else should I look for when I tear into the case...one more time lol.

[Kahuna]

Hi Dan
A couple of things usually cause the problem you're having:
Either the synchronizers or the end clearance on the main shaft.
Someone else may have some other ideas, but this has been my experience.
Bummer, as I think the trans has to come out.
Oh, maybe it could have something to do with the shift levers?
Best
Jim

[rotorwrench]

If you set the counter shaft cluster gear end play correctly then you can rule that out unless there is uneven wear going on in there. The 2nd gear bushing may have too much clearance on the main shaft which could be either gear bushing or shaft wear. If this is a post 1951 transmission it should have the late gears. Does it have a rectangular shaped side cover or does the cover have a round bottom edge like a T85? I just want to know what we are working with as far as the transmission is concerned.

[Hot Rod Reverend]

It has the rectangular cover, and it is not a T86 toploader. Just the run of the mill stuff. i have some good photos here:
https://www.hotrodreverend.com/in-pr...g/transmission

What gets me in all of this is that I had everything back together and the thing did really well for a few months. Now this. But, to be frank I only did a visual inspection, never checked the brass syncrhos against the cone, never looked at end play, and all the rest. I did replace the countershaft (not the gears, they were good) and the needle bearings. The transmission, I was told, was from a car with no issues... presumably a 55 Mercury but I have no way of knowing. The casing end on the tailshaft is certainly different.

I did talk with Mac Vanpelt today. I am looking at $1500 or so for a rebuild.

Ouch.

I feel confident I can do this myself, just don't want to pull it in and out several times and miss something. I already had it out a second time to repair a leak that wouldn't stop, so we are back to yankin it out again I am sure.

[Dobie Gillis]

'55 Mercs came with the T-85 and R11 OD. Fords with the 6 cyl or 272 had the T-86 and R10 OD. I'm not sure about '55 fords with the 292.

[rotorwrench]

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The transmission you have is likely from a 1954 car. It's the updated version of what Ford was using back to 1949 & back to early 1951 on the Mercs. Some of the parts are interchangeable with the older post 1951 transmissions so they shouldn't be any problem to get. The same problems can happen on the earlier units back to 1939. It likely has the same basic synchronizer assembly. Mac VP will treat you right on parts and he is a wealth of info. If you don't have his transmission book then you might consider purchasing it. It covers a lot of the stuff that crosses over into that transmission. The OEM shop manual for the mid 50s cars should cover the overdrive and the basic transmission works. My 1949/early 51 Merc transmissions are similar to yours as well.

The T85 with R11 is the best one of that era but they are expensive when you find one. I see them on flea-pay now and then. A person should look at it personally when paying a lot of money. They all wear out and owners don't always give you the straight skinny on condition.

[Hot Rod Reverend]

Did you guys see the odd end of the tailshaft? So is that a 54 Ford transmission? The solenoid was 12 volt when I got it but I guess you can swap a 6v and 12v easily so that’s no indication.

[Dobie Gillis]

I couldn't find the pic. I have a trans out of a '54 Ford in my '53. If you can post the pic again I'll have a look at mine for comparison. If I can't ID it maybe someone else can. Mac VP surely could.

[rotorwrench]

The Ford/Borg Warner R10 design and the T-85 Borg Warner R11 design had the same bell housing bolt up pattern in the early to mid 50s and even later on some applications. The Ford/BW designs were all similar after 1951 for both Ford & Mercury cars. I think they all still used the same drive shaft knuckle on the back. The input shaft and throw out bearing set up is where you have to be careful when swapping around. The tail shaft can also be different on some due to mounting changes.

T-85 units were used in Lincoln cars that had Overdrive but a lot of up scale folks were going automatic in that time frame so those early ones aren't all that common.

[Hot Rod Reverend]

Fellas! Been a while since I responded to this issue on the forum but I did want to thank you guys for the advice. The fuller version is found here:
https://www.hotrodreverend.com/singl...d-transmission

But, suffice to say, I discovered that the thick, modern gaskets I installed between the snout and main case, the main case and the OD adapter, etc, had given almost a 1/4" EXTRA end play... CRAZY I know but that was what I discovered. I did put new brass syncrho rings in it since I had it all apart again (the old ones did not seem worn but these are relatively cheap insurance), and used OEM gaskets and light sealer. I am happy to report, no leaks, no runs, no errors. She stays in second like a champ, through thick and thin.

Special thanks to Mac VanPelt as well for his advice over the phone some time back.

[Anteek29]

Sweet! Happy that ended well for you!

[Ford56]

Always good to read how it turned out, and what the problem was. Thank you for the update.

[KULTULZ]

Originally Posted by Hot Rod Reverend

...I discovered that the thick, modern gaskets I installed between the snout and main case, the main case and the OD adapter, etc, had given almost a 1/4" EXTRA end play...

Can you give the source of the OS gaskets and where (and brand) of the correctly sized gaskets?

[Hot Rod Reverend]

Would you believe, fleabay?

Part number B2A-7153-A

Item number 401266404955

[JimNNN]

Glad it's working well now. Congratulations on figuring out the problem. I have a '54 Ranch Wagon with a Borg Warner overdrive, so I might run into the same issue some day...so thanks for sharing info an advice.