Side-Shift Transmission

[bighealeysource]

Hey y'all,
Okay here's an interesting one - the side shift trans on my 100M/BN2 will at times, when I have been driving for awhile and going through the gears up and down, exhibit a tendency to be difficult to get into gear. Guess best way to explain is I'll be in 4th, then look to downshift into 3rd or perhaps into 2nd, and becomes difficult to slide into the selected gear. Clutch adjustment is good BTW. Trans was completely rebuilt about 10 years ago by Healey Surgeons (OD also) and seems to occur after driving for 30 or 40 minutes. Not starting out at all, only when well heated up. When it happens I will get it back into "neutral" and then carefully go into gear and proceed from there. I know enough about transmissions to know not to touch them ! Any thoughts ?
Thanks,
Mike

 

[gonzo]

Shoe choice? I sometimes wear a different shoe on a drive and noticed the joggers, Brooks with spongy soles, don't do a good job actuating the clutch resulting in a difficult shift. A harder sole works best for shifting through gears.

 

[Jack T]

Excellent thought from Gonzo. Shoes could make a difference. My first instinct would be oil level / choice. Once the oil in the tranny gets hot it will lose some of its lubricity. It may be time to top up or refresh the oil.

 

[bighealeysource]

Hey guys,
Wish it was that easy as wearing same shoes and just changed out the 40 wt, non detergent I run in it ! But I will try to be more aware
if perhaps my size 11's are tripping over each other !
Thanks,
Mike

 

[BoyRacer]

As a general rule I do not post anything unless I know exactly what I am talking about. However, I'm pretty sure that the soles of your shoes have nothing to do with it and that oil does not get less slippery when hot.
The symptom you are describing suggests to me that a particular clearance of some sort inside the case is tightening up because of heat expansion.
Is this a new phenonenom, or has it always happened since the trans was rebuilt?
Don't be afraid to open up your transmission. They are pretty basic. Just keep track of the ball bearings.

 

[roscoe]

Somewhere here I've posted about this before. I had a similar sounding problem with my sideshifter. It is difficult to describe because it was so odd and so intermittant. The gearbox worked flawlessly, along with the OD for some period of time and numerous excursions, until it wouldn't. It never misbehaved unless I stopped and went through neutral. Then, on rare occasions it was as if the entire shifting pattern had gone haywire. Sometimes when putting it into gear I couldnt find first or second and the shift lever went places it normally wouldnt be able to move and felt " wobbly". Sometimes I could find a gear but it wasn't first or second and it seemed as though more than one gear may have been selected at once and it was locked up if I tried to release the clutch and would have stalled without moving if I'd continued to release it. Sometimes it would go into a gear but it would be 3rd or 4th and lug from a stop. It had nothing to do with OD use. The weird part is it never stranded me. All of a sudden it would resume normalcy and I could go through the gears and the rest of the trip would be absolutely normal and remain so for weeks. I never could put my finger on it and thought it must have involved the interlocking ball bearings of the detent mechanism on one of the shafts.

The ultimate fix was installing a Toyota 5 speed. It was only a matter of time before it got worse. At this point in my life I'd rather pull all my teeth than pull a transmission by myself and find out I needed a part made from unobtanium. I'm sure someone knows exactly what caused my issue but they didn't come across my post and if they had they probably wouldn't have been a close neighbor. Sorry, not much help here.

 

[Bob_Spidell]

Since we're spitballin' I'll throw mine. Sounds like classic symptoms of worn synchro--'baulk' for the Brits--rings. There are two, one for second gear and one for 3/4. Typically, 2nd wears out first since that's the 'cornering' gear you tend to go in and out of the most (not a hard-and-fast rule, but common). Early boxes had brass synchros and later had steel; I suspect the brass ones wear faster, hence the change (brass may work better until worn due to it being a softer metal, but I don't know for a fact). It's odd that both would wear, but if you have more than, say, 50K miles on the box--HS would certainly have replaced your synchros if they were at all worn, and probably as SOP--it's not impossible. Mileage isn't a hard-and-fast gauge, as 50K 'city' miles is harder on a box than 50K mostly highway miles.

What oil are you using? Engine oil, as recommended by the shop manual, is adequate most of the time, but you might try a modern synthetic oil designed for manual gearboxes just for grins. I've changed out OEM oil in two brand-new Mustang GTs and felt shifting improved (confirmation bias certainly played a role). Both my Healeys get Redline MT-90; I felt shifting improved in my BJ8 though I wasn't expecting it (I wanted the O/D to engage quicker when hot, which it did).

 

[Jack T]

Hey y'all,
Okay here's an interesting one - the side shift trans on my 100M/BN2 will at times, when I have been driving for awhile and going through the gears up and down, exhibit a tendency to be difficult to get into gear. Guess best way to explain is I'll be in 4th, then look to downshift into 3rd or perhaps into 2nd, and becomes difficult to slide into the selected gear. Clutch adjustment is good BTW. Trans was completely rebuilt about 10 years ago by Healey Surgeons (OD also) and seems to occur after driving for 30 or 40 minutes. Not starting out at all, only when well heated up. When it happens I will get it back into "neutral" and then carefully go into gear and proceed from there. I know enough about transmissions to know not to touch them ! Any thoughts ?
Thanks,
Mike

Thinking about it some more, this is a classic symptom of less than optimum clutch hydraulics. You say clutch adjustment is good, but the seals in the hydraulic system could be failing or the fluid is old. And as with any fluid, performance will vary with temperature. You might try giving your system a good flush with fresh fluid and see if that improves things.

 

[Bob_Spidell]

BN2s have a mechanical clutch (though can be retrofitted with hydraulics).

Clutch 100-4

Clutch 100-4

mossmotors.com

 

[bighealeysource]

Somewhere here I've posted about this before. I had a similar sounding problem with my sideshifter. It is difficult to describe because it was so odd and so intermittant. The gearbox worked flawlessly, along with the OD for some period of time and numerous excursions, until it wouldn't. It never misbehaved unless I stopped and went through neutral. Then, on rare occasions it was as if the entire shifting pattern had gone haywire. Sometimes when putting it into gear I couldnt find first or second and the shift lever went places it normally wouldnt be able to move and felt " wobbly". Sometimes I could find a gear but it wasn't first or second and it seemed as though more than one gear may have been selected at once and it was locked up if I tried to release the clutch and would have stalled without moving if I'd continued to release it. Sometimes it would go into a gear but it would be 3rd or 4th and lug from a stop. It had nothing to do with OD use. The weird part is it never stranded me. All of a sudden it would resume normalcy and I could go through the gears and the rest of the trip would be absolutely normal and remain so for weeks. I never could put my finger on it and thought it must have involved the interlocking ball bearings of the detent mechanism on one of the shafts.

The ultimate fix was installing a Toyota 5 speed. It was only a matter of time before it got worse. At this point in my life I'd rather pull all my teeth than pull a transmission by myself and find out I needed a part made from unobtanium. I'm sure someone knows exactly what caused my issue but they didn't come across my post and if they had they probably wouldn't have been a close neighbor. Sorry, not much help here.

Hey Roscoe,
Yep, what you describe sounds like my issue although mine is not as severe as yours. Had a friend who races old LBC's and he said
when it happens to get it out of gear - neutral - and then methodically go through the gears in order. Something about resetting
the innards - my term for trans bits. I almost did the 5 speed fix but since it is a 100M, want to keep original. I've pulled that lug of
a trans before and now that I'm almost 75, not sure I could do it again !
Thanks,
Mike

 

[Bob_Spidell]

"... it was as if the entire shifting pattern had gone haywire ..."

The laygear and reverse gear can only rotate; the others gears slide in and out of adjoining gears but mostly rotate (and not when the clutch is disengaged, in neutral and car is stopped). The parts that could go haywire are the forks and the selector rods; is it possible one of the set screws has loosened on one of the forks, allowing it to wander sideways? They are the only parts I know of that are safety wired (used threadlocker as well). There should be a small pad in the bell housing that prevents the rods from moving too far forward and causing grief, and Magnus Karlsson deepens the notches on the selector rods (not sure what that achieves).

The thought of one of the set screws securing the shift forks working loose and falling into the gears made me real nervous. Doesn't explain the cold vs. hot behavior, though

 

[bighealeysource]

"... it was as if the entire shifting pattern had gone haywire ..."

The laygear and reverse gear can only rotate; the others gears slide in and out of adjoining gears but mostly rotate (and not when the clutch is disengaged, in neutral and car is stopped). The parts that could go haywire are the forks and the selector rods; is it possible one of the set screws has loosened on one of the forks, allowing it to wander sideways? They are the only parts I know of that are safety wired (used threadlocker as well). There should be a small pad in the bell housing that prevents the rods from moving too far forward and causing grief, and Magnus Karlsson deepens the notches on the selector rods (not sure what that achieves).

The thought of one of the set screws securing the shift forks working loose and falling into the gears made me real nervous. Doesn't explain the cold vs. hot behavior, though

Hey Bob,
Might pull the trans tunnel cover and take a peek at the trans but that will wait until Spring ! Been fiddling with the brakes and just got the
wheel cylinders on right front and rear replaced. Determined my power bleeder just doesn't get the job done so going to ask a buddy
to come over and do it the old fashioned way !
Thanks
Mike

 

[AUSMHLY]

Hey guys,
Wish it was that easy as wearing same shoes and just changed out the 40 wt, non detergent I run in it ! But I will try to be more aware
if perhaps my size 11's are tripping over each other !
Thanks,
Mike

When I asked Healey Surgeons what oil to use, Bruce said 30w non detergent. Have you tried that vs 40w non detergent?
Napa has 30w non detergent on sale right now. It's their label made by Valvoline.

 

[bighealeysource]

When I asked Healey Surgeons what oil to use, Bruce said 30w non detergent. Have you tried that vs 40w non detergent?
Napa has 30w non detergent on sale right now. It's their label made by Valvoline.

Sorry, meant to reply to your question on using 30wt vs 40 wt. Might change it out to 30 wt and see if that makes any difference. I have been using the 40 wt since the O/D seems to like it and maybe holds up better under higher temps. But maybe that's the problem with the trans, viscosity when the 40 wt gets hot is the issue ?