Fiesta poor downshift to 1st

[borgward]

The original 5 speed manual in my 2013 Fiesta SE 1.6 DOHC never liked to downshift into 1st. I had to be at a crawl below 5mph. I have read of several complaints from other people. I just installed a used IB/5 Transmission. It has no problem shifting into 1st, even from 10MPH. Very smooth. I don't know if this IB/5 came from a Fiesta, or something else. That transmission was put in the Focus and other cars. Was it only the Fiesta that had this issue? If so did it start at a certain year model?

 

[scotman]

They are designed to NOT be easily force down shifted! Imagine how catastrophic that would be at even just 40 mph. Forced down shifts are not desirable for multiple reasons. The only time that would be acceptable is if the car has lost all brake pressure and the driver is trying to scrub off some speed to not crash as hard. That situation would involve something like a 5th down to 3rd kind of action.
Forced downshifts feed a tremendous amount of torque back through the gearset, timing components and valvetrain. You are basically using engine compression to slow down the car.
But first gear is intentionally designed to not be usable at any speed above a crawl.

 

[borgward]

The idea that you can't shift into 1st unless you are slower than 5 MPH is a bogus idea. I have never had a manual transmission that you had to be that slow to do so. I never had to be that slow with our Escort or any other car that had synchro on 1st going all the way back to the 1963 TR3-B. Somebody messed up engineering the 1st gear synchro on the IB/5 transmission.

 

[scotman]

No, it’s not. It’s common sense to restrict the ability to hit that cog while in motion. Very bad and violent things can happen that will reward you with getting to know a tow truck driver

 

[borgward]

I'm sorry but it is not common sense to not allow a shift to first from 2nd unless you are under 5 MPH. That's ridiculous. Maybe the engineer assumed that the only reason a person would shift into first from second would be for engine braking. There are times when you have slowed down and are in 2nd but need to accelerate but you will be lugging the engine because the RPMs are too low to accelerate so you need to go into 1st to be in a proper RPM range to do so. Maybe somebody is reading a text message behind you and you want avoid being rear ended. This is the 1st car I have ever had w/1st synchro that would not work properly. A lot of people have made this complaint.

 

[Handy Andy]

The poor downshift can be from other factors up to and including a gearbox cable adjustment.

When it happens from day one, the issue may come from a poor quality control issue that was not followed up on by a dealer. IT can mean this could have been something as simple as a bent pivot or a cable length not properly set - even onto the issue of the shifter case assembly being the wrong size or configuration (shift pattern can change when they use a different shifter lever) to multiply force that you see and a longer or shorter throw inside the car as the shifter pattern for the size of the pivot and levers used. A box (the external cover that protects the levers and gimbals from dirt) too small to let the gimbals move without striking the case cover - can make it nearly impossible to shift up or down in some conditions - because letting out the clutch - the gears are still spinning - makes for some gyration - some gyroscopic motion events; and the torque needed to move the levers exceeds the tension the cable can place on those gimbals to move to another gear until it spins down enough to let the lever and the gimbals force the forks of the gear to move.

When you switched to another gearbox, the shift was smoother, so to me it seems the "lockout" the previous transmission had, was possibly damaged or the gear cable needs to adjusted onto the shifter levers - the ones out side that work off those gimbals, needed to be inspected - cleaned up - re-lubed and reinstalled.

The opposite can also be true - that one set of gears on a shaft and it's bearings were loose from the onset, and this was an event only waiting to happen. The gear shaft wouldn't tame down or dampen so the mesh effort needed was greater than the ability of the cable to supply the force needed until it was at a near dead stop.

The (owners manual suggested) maintenance is needed to help bring back that oomph to move the shifter lockout pivot that "sees the 1st gear turning" and holds the fork and it's synchronizer out of the mess until it can spin up that whole set of gears on the shaft letting the synchronizer follow the spline track to let the 1st gear hit the splines to engage that shaft.

That takes some leverage - and that also forces the cables to press down into the gimbals on those pivots.

Problem is; this whole thing is a dealer issue for the required adjustments are specific to the vehicle, it's transmission and so you need an experienced mechanic whom understands the gearbox to do the proper adjustments to make this work

Because the 1st gear is the most radical and radial of the set, it also has the most mass when you try to force a spin-up to match the drive train splines to the engine sides' of the meshing - to do that, it's left to the synchronizer and that is the reason for it's lockout - its gotta' move all those gears and their mass - so if there's issues around the gimbals moving those outside levers to pivot the forks, and the range of the shifter cable is binding on the outer extremes (like 1st and Reverse) - swapping gearboxes solved a condition, but not sure if the condition was due to a bad gearbox, or just bad or poor lubing of the external shifter levers of the original gearbox and that got solved by using a different gearbox.

Let alone internal issues during assembly and prior damage we're not aware of.

There have been issues around bad rebuilds because the case got deformed during the rebuild - which creates another mess in itself - since we don't know the history of that previous gearbox during it's assembly creation onto the install into your Fiesta from the factory - a lot of variables can occur we don't see or aren't even aware of. They are built is various countries and use parts from various sources - so you looking as a cascade of events leading to this disappointment.

 

[borgward]

As for the cables I checked them out and everything was OK in that respect. In fact I made no adjustments to them for the used transmission. You could shift to any gear standing still and the "H" pattern inside the car at the shifter was not misaligned. I think that rules out any cable problem.

What Lockout are you referring to? A particular part, or just the condition? Some people assert that there is a Lockout mechanism and the IB/5 was designed not to shift to 1st above 5MPH but I doubt there is such a part or that it was designed not to shift to 1st above 5MPH.

As for "1st gear is the most radical and radial of the set, it also has the most mass when you try to force a spin-up to match the drive train splines to the engine sides' of the meshing - to do that, it's left to the synchronizer and that is the reason for it's lockout - its gotta' move all those gears and their mass ...", That may be the reason, but I have never had a manual transmission that was not designed to overcome those problems. Our 99 Escort has a 5 speed manual and has no problem shifting into 1st with out having to slow down below 5 MPH. That makes me think it's a design flaw. After all, that was a 4 speed transmission that had a 5 speed tacked onto the end. They should have just designed a 5 speed from scratch.

I would not trust the used transmission on a 4,000 mile round trip. I suspect it shifts into 1st because it has a lot of wear.

As for the experienced mechanic whom understands the gearbox I have not been able to find one. Those guys are just about history. That's why I am rebuilding the original transmission myself.

I will inspect all the gears, shafts and bearings for problems when I disassemble the transmission. I bought the Fiesta new and it never wanted to shift into 1st below 5 MPH and lots of others have made the same comment.

Do you know what the part numbers for the first gear synchronizer parts are?

I don't expect to be able to shift easily to 1st after the rebuild. I will just live with it. The transmission would pop out of gear from starting from a standstill sometimes and I was afraid that the whole thing might blow up on me on a long trip.

Any advice about rebuilding the original transmission would be appreciated.