RPMs limited in 4L reverse?

[Limestone]

While off roading in the snow today, I had to reverse in 4L up a long hill. I noticed that the truck would not rev any higher than 3500 rpm, and when I let off on the accelerator a bit and then tried to increase the rpms, the truck was limited to 2500 rpm. When I returned home I was able to replicate the same event on my driveway. Has anyone else noticed that the rpms are limited in this way while in reverse in 4L. I searched the owners manual and used the search function for this forum but could not find any information about this.
2021 JTR
Automatic Transmission
5 position transfer case

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[Almost]

Don’t have answer for you, but I could certainly see there being a limiter. Helical gears ran in reverse are not as strong so they maybe limiting power for those reasons in 4L. This is why you should never tow in reverse and winch with your brakes on.

Straight cut gears can be ran either way, but are rarely used today in passenger vehicles and mostly used for race applications. The only vehicle I know with straight cut gears are Hondas which is why they make that higher pitched sound in reverse - that is the sound of straight cut gears. Why they only use it for the reverse gear I have no idea.

 

[ShadowsPapa]

Don’t have answer for you, but I could certainly see there being a limiter. Helical gears ran in reverse are not as strong so they maybe limiting power for those reasons in 4L. This is why you should never tow in reverse and winch with your brakes on.

Straight cut gears can be ran either way, but are rarely used today in passenger vehicles and mostly used for race applications. The only vehicle I know with straight cut gears are Hondas which is why they make that higher pitched sound in reverse - that is the sound of straight cut gears. Why they only use it for the reverse gear I have no idea.

Sorry, been dabbling in machine shop, worked on transmissions for years, and have had to study different gear types.
Your info is quite flawed (and I know the reasons they only use the straight cut gear for reverse - having rebuild many dozens of transmissions)

They are as strong either direction - it's just that the thrust is in different directions (the AXIAL loading varies)
The thrust may be forward in one case, and the gear thrown back on the shaft in another.
But there can't be any difference in strength because the teeth are identical on both sides.
Check the machinery handbook for the details.
Helical gears are STRONGER. There's actually more surface area, the load is spread out.

Here - from the experts -

And here is where they are used - and why -

They handle higher loads and greater speeds.

Planetary gears can be used in any direction with the same torque handing ability either way - as long as the thrust surfaces are the same on each end.
I don't know where the never tow in reverse comes from......

Straight cut gears are still used for reverse gears in manual transmissions.
Automatics use helical gears.

This shows reverse in one of the transmissions I worked on, plus the helical gears inside.

 

[Limestone]

While off roading in the snow today, I had to reverse in 4L up a long hill. I noticed that the truck would not rev any higher than 3500 rpm, and when I let off on the accelerator a bit and then tried to increase the rpms, the truck was limited to 2500 rpm. When I returned home I was able to replicate the same event on my driveway. Has anyone else noticed that the rpms are limited in this way while in reverse in 4L. I searched the owners manual and used the search function for this forum but could not find any information about this.
2021 JTR
Automatic Transmission
5 position transfer case

 

[Limestone]

Interesting discussion about gears and all, but has anyone noticed or can confirm that this rpm limiting in 4L while in reverse is “normal” for all gladiators?

 

[ShadowsPapa]

Were you on off road + mode?
It changes the pedal calibration -

 

[ShadowsPapa]

Interesting discussion about gears and all, but has anyone noticed or can confirm that this rpm limiting in 4L while in reverse is “normal” for all gladiators?

I was just pointing out it's zero to do with gears......... sometimes there's a lot of random guessing - stuff tossed at the wall to see what sticks. Gears was a wild one.

 

[Limestone]

Were you on off road + mode?
It changes the pedal calibration -

Yes, it was in off road+ and both axles were locked. The rpms were limited to about 3500, then 2500 even when the accelerated was floored. I had the same situation on my level 500’ gravel driveway later that day.

 

[Limestone]

I was just pointing out it's zero to do with gears......... sometimes there's a lot of random guessing - stuff tossed at the wall to see what sticks. Gears was a wild one.

Thank you for your response and taking the time to help.

 

[ShadowsPapa]

Yes, it was in off road+ and both axles were locked. The rpms were limited to about 3500, then 2500 even when the accelerated was floored. I had the same situation on my level 500’ gravel driveway later that day.

The pedal is "de-gained" meaning when you floor it, it won't 'open the throttle' as much, so that may be it.
OR+ in 4H seems to put it more in a sport mode where in 4L it dulls the responses of the throttle.
It's supposed to help with pedal jerking while in rough ground - as the vehicle bounces, so does your foot on the gas pedal. This dulls that effect and likely limits RPM.

 

[Lunentucker]

Try turning off traction control. I have seen some mention that it's what's causing the issue and not a reduced RPM rev limiter.

 

[ShadowsPapa]

Try turning off traction control. I have seen some mention that it's what's causing the issue and not a reduced RPM rev limiter.

RPM was limited - I guess traction control can do that.
This is one of the other effects of OR+

I noticed that the truck would not rev any higher than 3500 rpm, and when I let off on the accelerator a bit and then tried to increase the rpms, the truck was limited to 2500 rpm.

 

[Limestone]

RPM was limited - I guess traction control can do that.
This is one of the other effects of OR+

Try turning off traction control. I have seen some mention that it's what's causing the issue and not a reduced RPM rev limiter.

I believe traction control is turned off in 4L.
The pedal is "de-gained" meaning when you floor it, it won't 'open the throttle' as much, so that may be it.
OR+ in 4H seems to put it more in a sport mode where in 4L it dulls the responses of the throttle.
It's supposed to help with pedal jerking while in rough ground - as the vehicle bounces, so does your foot on the gas pedal. This dulls that effect and likely limits RPM.

This wasn’t a muted response.

 

[Limestone]

This wasn’t a muted response.

If someone could try 4L in reverse in their truck and report on the response it would be appreciated.

 

[Lunentucker]

I'll try tomorrow if I remember.
Meanwhile this is what I see when the resident genius posts detailed themes on some subjects.
Makes my head hurt and I get nose bleeds.

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