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.

 

[Handy Andy]

There is a small "feather" key the rolls along - skims - the 1st gear that lifts out and prevents the 1 gear sync from letting the two gears mesh unless it is below a given speed...

The problem is - how is that speed determined?

Simply put, the gears churn oil as they work, as long as 1st gears are moving they pull oil up and over themselves - so the feather key is a simple lever that is lifted up and prevents the synchronizer from letting 1st fall into place - 2nd gear is not affected by the feather key position. The key is lifted by the gear oil pressure and simply blocks the 1st gear side from engaging - but does not keep the synchronizer from operating 2nd gear.

The spin of the gears turns the key but the pressure of the oil lifts the key up out if it's keyway - the missing piece of the puzzle, when the gear lube skims over the gears teeth - throwing the lube into the keyway keeps that key from letting the synchronizer to fully seat into the gear set - but lets the synchronizer press the gears into a mesh pattern but is locked out because the key is lifted and turned towards the groove the synchronizer would use to finish the throw action onto !st gear - due to the dynamics-of the required torque and spin rate - the feathered key and it's design keeps the meshing from completion until the pressure or spin has dropped and the key can then set into keyway - freeing up the groove to let the mesh drop into place

You can experience that during the downshift, you should be able to hear the whine from the over-spin as the synchronizers pull/push the gears to meet - happens in every gear. However, as you may try; if you try to mesh 1st - remember the output pinion and ring gear ratios - they affect and become multiplier of the spin rate - making matter worse is they went with a 4.12 to 1 Pinion to Ring gear ratio - versus a lower ratio of 3.8x to 1 to help reduce the multiplied spin that the pinion is not making 1st Gears try to spin up to to meet - it's not just the engine side, it's the drive-shaft that adds the spin to this mess.

The gears are massive compared to something like Toyota - where they remove some of the useless mass in the gears to help them spin up and down faster with to less inertia and momentum working against their synchronizer.

Not sure if you had time to verify oil levels - for the IB5 is kind of fussy in that - both in viscosity - thinner oil when its warmed up lets the key fall faster - and less oil churn (foam) that helps keeps the key submerged in fluid not made buoyant from foam or thicker fluid volume amidst pressure from excessive oil levels in the case; making some simple changes can offer some help in letting the 1st gear engage faster.

You're talking to a guy that got stranded from a small plastic clip that broke in the cable box at the transmission - a yellow clip came off the Gear Selector Fork cable - making it impossible to shift the car in or out of gear while driving - immediately puts me on the side of the road and unable to figure out how to get it towed without damaging it further let alone what the hell went wrong with it.



Had to have the transmission replaced due to the amount of damage that happened - the above is my older transmission gearbox selector lever cover showing the two gimbals - before the clip broke.

What does the clip do? Keeps a set of serrated teeth on the Fork selector cable - your side to side motion - to help the forks line up to engage the gear you push or pull into - engaged on the lower gimbals. When the clip is gone, that part of the shifter forks alignment is shot - you're at the mercy of the gearboxes own floating selector rod and its forks shifting into whatever they want.

So, I'm no expert but the reason why I wanted to post in here was to help you find options that may help you enjoy your transmission better without having to have it torn apart and figure out what you really wanted - was a new start and work with that.

Basically, the Fill Plug shown in the photo - is really a level check - if fluid drains out - you've got either too much fluid or you have oil churning which increases the volume of the fluid and both affect how the 1st gear syncro and key will work together,

I've done up a copper wire from an old House wiring cable - using the white wire, and use a convenient length to reach the fill plug and made a L-shape of 1cm or about 1/2" inch on the end so when you stick it in; with the L portion on there down - you can use the L portion as a dipstick to tell you how much fluid is really in there. If it touches the lower tip - you're all set but if it comes up some distance of the L you may need to use a turkey baster and some vacuum tubing as a means to suck out extra fluid to help with reducing the foam, or changing / displacing some fluid to add in modifiers so you can change how the fluid acts in the gearbox.

Another thing too, so we are on the same page, run your VIN. Because if they had to change the Gearbox to meet specific sensory needs like speed sensor or Traction Control - they did make up a Limited Slip Differential gearbox option for Fiestas.' - so if you find out on your VIN you have a LSD - it may explain the reason for the difficulty in having to downshift - for LSD differentials and traction control on icy pavements when you're trying to downshift into first - can damage the LSD from it trying to take up slack from the syncros trying to spin down and the resulting torque hammering on the drive-train due to it.

 

[borgward]

I did VIN lookup and LSD was not even an option. The car did come with an electronic BS traction control which is difficult to turn off permanently. The used transmission I installed has 2.5 quarts of fluid in it which is more than the recommended 2.2 quarts. Never came up to the fill port. It will downshift to 1st from 10MPH easily.

As for not rebuilding the original I do not think that is an option as it pops out of 1st when taking off. There were no cable or shifter problems.

Is there a picture and/or P/N of that feather key?

 

[Handy Andy]

The forums here have some "talk" including my own - the feather key - I call it that by it's nature but the lockout is by Motorcraft standards is integrated into the 1st Gear synchronizer.

​

See this thread for example...

https://eco-torque.co.uk/blogs/news...bc13DMD6e0VjqCHbKw1MgzXEMATISZIE_vwJJDeSyFc8p

Battered teeth is usually the result of too much torque from the fork - applied...

 

[borgward]

Thanks for the good info. Too high fluid level would tend to lift the key, and too low level would tend to not lift the Key? I will check the fluid level tomorrow. If there was no key the 1st gear synchronizer would engage at higher speed with the resulting crunch?