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Discussion Starter · #1 · (Edited)
Max Transmission RPM? Will it blow?

Hi folks. First post but I have learned alot on this forum.

Just converted an 84 Ford Ranger to EV. It has an AC51 motor 144volt with manual 4 speed tranny.

Drives great and I usually leave it in 2nd or 3rd gear and do not bother shifting.

However, I have a question about the tranny and max rpm.

Lots of discussion about manual transmission, clutchless vs clutch, etc. I know the electric motor can run at higher rpms but what about the tranny?

I notice my transmission tends to get really noisy about 2500 rpm and above. Before with the ICE the revs were always kept around 2000-3000 rpm while up and down shifting. In that range it is not too noisy.

SO isn't the tranny designed for this narrow range? Isn't it bad for the tranny to not shift up and down with the electric motor? At higher rpm (3500-5000, say) the tranny is making alot of noise.

Cheers!

PS changed the oil in the tranny already to see if that would quiet it down but did not make much difference.
 

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Discussion Starter · #3 ·
Let's put aside the noise. I am more curious about the operating range for the transmission.

Can you run the transmission at 5000 rpm for long periods at a time?

Is it made for that?

So for example if I put the truck in 2nd gear and leave it in 2nd gear and drive around town at 50 mph it will be running around 5000 rpm.

If I put the truck in 3rd gear and leave it in 3rd gear and drive around town at 50 mph it will be running around 4000 rpm. That still seems to me too high.

Cheers!
 

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why does 4000 rpm seem to high? because of the noise? Normally I wouldn't give sustained 4000 rpm on a gearbox a second thought, provided it wasn't complaining. I can't simply say "It's ok" under these circumstances though. But if you don't want to discuss it or look into it then I guess thats that.
 

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Assuming the motor/transmission alignment is right, then is the noise just gear whine? You are always going to hear more of than in an EV with a transmission just because the engine isn't drowning it out.

You didn't say what you changed the oil to. I like redline superlight shockproof. Its a lightweight full synthetic that does not have the friction modifiers used in most gear oils for posi differentials.

If you have any way to monitor gearbox temperature, that might be an indicator if something is wrong. If the gearbox is getting hot (assuming you have enough range to drive 30 minutes to an hour at freeway speed) that could be an indicator that it is overspeeding or otherwise having problems.

You can look at changing the rear end gear ratio to allow yourself to run in higher gears (e.g. go from a 4.10 to a 4.77 rear end) and that might allow you to run in a higher gear more of the time. Not sure what the standard rear end in an older ranger is or what others are available but sure the info is out there.
 

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Let's put aside the noise. I am more curious about the operating range for the transmission.

Can you run the transmission at 5000 rpm for long periods at a time?

Is it made for that?

So for example if I put the truck in 2nd gear and leave it in 2nd gear and drive around town at 50 mph it will be running around 5000 rpm.

If I put the truck in 3rd gear and leave it in 3rd gear and drive around town at 50 mph it will be running around 4000 rpm. That still seems to me too high.

Cheers!
If the Trans. and the motor are properly aligned and assembled with the right oil in the box, the trans. should be fine. Without photos and/or an explanation of the separate parts and how they're put together, we really can't be much help.
 

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Not sure which version trans you have, toyo ktogo, mitsubishi, whatever. Gen 1 thru 3 were constant mesh and they have straight gears that whine. Mine makes enough noise to be used as a warning device in parking lots, particularly in 4wd low. It wont whine in 4th 2wd hi because that is direct drive. As far as max rpm I don't know. I try to gear it for running at 3000 rpm as that keeps the motor coolest. It is splash lube on the bearings so I suspect they wont like lots of sustained running at 5000 rpm.

This is old tech. Good enough back then, not so much today
 

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Discussion Starter · #8 ·
Thanks everyone for your replies.

Sorry, I guess I should have maybe made this two posts - 1) 4speed transmission rpm and what is it designed for

and b) my tranny noise.

So for the first one I was thinking like this:

The ICE engine and 4 speed tranny are designed to work together. The ICE motor has a different power band than an electric motor and needs the gears to operate within it’s rpm power range. The rpms can spike a bit but usual driving hovers around 2000-2500 rpm.

Cruising speeds around 50 mph the rpms are maybe 3000 rpm. So the tranny never really runs for long periods at 4000 rpm or 5000 rpm because that is not what the ICE runs at.

But now I have the AC51 connected to a tranny designed for the ICE. The AC51 can cruise at 4000 rpm no problem.

But is it good for the transmission?

Is it built for higher rpms for long periods at that rpm?

I have read on the forums that many people just leave the vehicle in one gear and drive without shifting. That would be my preference.

If I leave it in 2nd gear it is better around town in traffic but 3rd gear seems better at higher speeds. So if the rpms are not an issue for the transmission I would leave it in 2nd.

If it is better for the transmission I can reintall the clutch pedal and just shift up and down like before when it had the ICE.

Cheers!
 

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Discussion Starter · #9 ·
Not sure which version trans you have, toyo ktogo, mitsubishi, whatever. Gen 1 thru 3 were constant mesh and they have straight gears that whine. Mine makes enough noise to be used as a warning device in parking lots, particularly in 4wd low. It wont whine in 4th 2wd hi because that is direct drive. As far as max rpm I don't know. I try to gear it for running at 3000 rpm as that keeps the motor coolest. It is splash lube on the bearings so I suspect they wont like lots of sustained running at 5000 rpm.

This is old tech. Good enough back then, not so much today
It has the Toyo Koygo. I have should have been more clear when I said noise. It just sounds like gear whine.
 

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Discussion Starter · #10 ·
Ok sounds like the consensus is the trans should be fine at higher rpms.

As far as the noise, when I bought the truck I drove it a few months and the truck in general was noisy. The motor was loud and it squeaked a bit and rattled etc plus it is a 33 year old truck. I don't think I could hear much of the tranny over the engine.

When I installed the AC51 it was so quiet, it was an amazing difference. So later I started noticing the transmission sounds which I think is just the gear whine.

It runs fine at higher speeds - no vibrations or anything. There is not much sound dampening insulation either so that maybe part of it. I am going to change the oil in the gearbox again with some Lucas oil and see if that helps.

Unfortunately where I live there isn't anyone else with an EV conversion that I can test drive or listen to so I am just on my own. Thanks for your feedback.
 

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When I installed the AC51 it was so quiet, it was an amazing difference. So later I started noticing the transmission sounds which I think is just the gear whine.
OK, this is a clue that something is wrong with the transmission-probably related to how it was put together with the electric motor. If you are willing to accept that and not that the problem is related to the design or limitations of the trans., we can probably help you. Properly mating an electric motor to a trans. is more difficult than most people realize.

If you want some help, please let us how you put the trans. and motor together.
 

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Discussion Starter · #12 ·
OK, this is a clue that something is wrong with the transmission-probably related to how it was put together with the electric motor. If you are willing to accept that and not that the problem is related to the design or limitations of the trans., we can probably help you. Properly mating an electric motor to a trans. is more difficult than most people realize.

If you want some help, please let us how you put the trans. and motor together.
Sorry what I meant was the truck ran much quieter with the new electric motor compared to before.

It was then that I could hear other sounds because the ICE wasn't covering them up. The gearbox didn't start making new or louder whining sounds.

Not trying to dismiss potential problems with the motor/tranny but just trying to eliminate variables and understand the design limits of the gearbox. I do appreciate the help.

The motor was mounted using a kit from CanEV. First I mounted a coupler on the shaft, then an adapter plate, then aligned the tranny to the motor and slide it into position. Slipped in pretty smooth I thought. Spun the motor/tranny by hand, no real resistance or weird sounds. Tightened up the adapter plate.

Cheers.
 

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That's a good start for mating the motor to the trans. Did you use the alignment dowels? Does the coupling provided have something to support the end of the trans. input shaft where the pilot bearing would normally ride? The splines alone, without this support, sometimes are a loose fit that might not support the end of the input shaft well enough.

Does this sound like a harmonic noise that has peaks at X RPM, 1/2X RPM, 2X RPM etc.? Have you eliminated the drive-line(drive shaft) as the source of the noise? Does the trans. have a lot of miles on it?
 

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No, noise is normal for a kyogo. :mad: they have straight cut gears. They have mesh whine. It aint an alignment problem or a bearing problem especially because of the can ev adapter. No synchro effect as they are constant mesh so they don't speed shift.

If you aren't shifting you can use 70w multi viscosity weight gear oil and it will quiet down some but be a bit stiff cold and use more watts. Im running a 50/50 mix tranny gear oil and that helped a bit.

The real issue is that the v6 was so noisy that is all you heard.
 

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Discussion Starter · #15 · (Edited)
No, noise is normal for a kyogo. :mad: they have straight cut gears. They have mesh whine. It aint an alignment problem or a bearing problem especially because of the can ev adapter. No synchro effect as they are constant mesh so they don't speed shift.

If you aren't shifting you can use 70w multi viscosity weight gear oil and it will quiet down some but be a bit stiff cold and use more watts. Im running a 50/50 mix tranny gear oil and that helped a bit.

The real issue is that the v6 was so noisy that is all you heard.
Awesome. Wasn't sure, now I know. Thank you.

So if I leave it in 2nd gear for city driving but occasionally cruise at 50mph that would mean 5000rpm. Would you say that the kyogo gearbox will be ok with that?

Sorry if I keep repeating this theme. It is just I have worked on alot of cars and driven alot of cars and just can't wrap my head around driving down the street at 4000 or 5000 rpm.
 

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No, noise is normal for a kyogo. :mad: they have straight cut gears. They have mesh whine. It aint an alignment problem or a bearing problem especially because of the can ev adapter. No synchro effect as they are constant mesh so they don't speed shift.

If you aren't shifting you can use 70w multi viscosity weight gear oil and it will quiet down some but be a bit stiff cold and use more watts. Im running a 50/50 mix tranny gear oil and that helped a bit.

The real issue is that the v6 was so noisy that is all you heard.
Are you sure this trans. has straight cut gears? I haven't seen a trans. that didn't have helical cut gears(except for the reverse gears and racing versions) for many moons now.
 

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"Constant mesh", "straight-cut gears", and other transmission characteristics

The working assumption here seems to be that the transmission is a Toyo Kogyo (Mazda) TK4 (manual 4-speed), which would be normal for a 1984 Ranger. It was used in many Mazdas and Fords, including the small pickups, related SUVs, and even sports cars (Miata, RX-7).

This is a constant-mesh transmission, like all automotive transmissions built in my lifetime. That only means that each gear stays in place and engaged with its partner gear all of the time... they're not slid along shafts to engage and disengage with each other. Shifting is instead done by sliding dogs (and synchronizers, in the case of a synchro box) to engage and disengage one gear of each pair from the shaft. Of course this is a synchro box; we're talking about the 1980's here, not the 1940's. ;)

While the gears of a non-constant-mesh transmission must have straight-cut teeth (parallel to the shaft) to allow shifting, a constant-mesh transmission can use straight or helical (spiralling around the shaft) gears. So saying that this is a constant-mesh transmission says nothing about whether the gears are straight-cut (noisy) or helical (quieter).

As electro wrks said, straight-cut gears have been rare (other than for the reverse gear) in production cars for many years, although they are still used in many racing transmissions. Which does the TK4 have? I did find an exploded view (from The Ranger Station's manual transmission page); although the gears appear to be helical, the image is so poor in quality that it is hard to be certain. My guess is helical, but I don't really know. I suspect the noise problem is not due to straight-cut gears.
 

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Starting in the 60's everything is helical cut, except for reverse. The expensive cars like BMWs had helical gears in reverse. The noise difference is huge. Think of the whining noise many cars make in reverse.
 

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re: straight cut and constant mesh. According to this
http://www.drivetrain.com/parts_cat.../ford_3_4_5_speed_reference_material_v26.html

some ford had a straight cut first/reverse sliding gear till 87, and some part of that may be spinning meshed (or viscous coupling). Don't know how the noise relates to load though. (actually with an idler gear, some straight cut part HAS to be meshed, no?)

But we are just reading tea leaves at this point, drive it and cross your fingers, or tear it down and inspect/repair.

TK4, mazda, no mention on that page though.

bit if it IS a tk4, they have an overhaul kit:
http://www.drivetrain.com/parts_cat...ts/toyo_kogyo_4_and_5_speed_overhaul_kit.html
 

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Oh I'm sorry, I just have one and have been inside it to rebuild it. I didn't google it to see how it works, I use the correct ford service manual. How obsolete.

The gears are cut on an angle, there is no helix curve to the cut. Hence my comment straight cut. Cheap mod to make the gears stronger learned from german WW2 submarine transmission. Since they are constant mesh, you dont care how the shift properties are, that isn't what is changing.
 
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