Manual Shift option wears out transmission

[Maximus Gladius]

Now that’s a pretty bold statement to make and post this thread saying it but now that I’m just past 4000k kms on my warranty replaced 4th auto transmission, …I decided to try driving this one a little differently to see if the manual shift feature, (I used a lot only for slowing down) had a significant roll in bringing about my third transmission’s demise and pump failure at only 32k kms.

As it was becoming apparent that the third transmission was experiencing problems and noted by the oil analysis lab to change the oil and filter because the IRON wear was too high, I had much time to critically think what could possibly be causing it’s failure. The 4th tranny was put in and I decided to not use the manual shift to assist in slowing down (which my brake pads benefited from) greatly and I wanted to see what impact this would have on the transmission in the wear department.

The first oil analysis proves the transmission is healthy right out of the gate and the second report was done at 3950k kms, pretty much at the same kms the third transmission report was done and we can see a HUGE reduction in wear not using the manual shift.

I’ve thought long and hard about this and the numbers don’t lie. Cause and effect law applies here and we can see this. I’ll be pulling samples and getting analysis reports at the same times as the third transmission to see if this theory holds true.

My conclusion is this 850RE transmission should not use the manual shift feature for slowing down if we can see expedited wear as a result. Now that said, I would use it if I’m coming down a mountain pass and I don’t want to burn the brakes out so there’s times it’s needed but it was far to easy for me to use it often in the city to slow down. It’s a cool feature so I used it. But I have also been able to not use it and be ok too. I figure brake pads are cheap andI’m still on my first pair at 80k kms.

(first image is 4th tranny)
(Second image is 3rd tranny)

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[Mr._Bill]

In all your posts, and your original saga on the replacement, this is the first time you have mentioned that you regularly subject your automatic transmission to this type of abuse.

 

[Maximus Gladius]

In all your posts, and your original saga on the replacement, this is the first time you have mentioned that you regularly subject your automatic transmission to this type of abuse.

You’re right, I never mentioned using this feature. Never thought using it was abuse. Now I can say my wife never used it cause she doesn’t know how. She just drives it.
Explain your rationale to say using something it comes with is “abuse”.

The dealership blames “Covid” as poor QC.

 

[ScottBeach]

We still wouldn't know if the 4th trans is working because of use change or lack of downshifting

I use manual mode. 50k miles. Still working fine. But. My shift is concurrent to brake use. Are you shifting down. Then braking. Or braking and shifting down.

 

[whysoserious]

I just read through all of your trials and tribulations with your vehicle... and it begs a question... have you thought about mass transit as your mode of travel?

 

[Maximus Gladius]

We still wouldn't know if the 4th trans is working because of use change or lack of downshifting

I use manual mode. 50k miles. Still working fine. But. My shift is concurrent to brake use. Are you shifting down. Then braking. Or braking and shifting down.

Braking and shifting down. The feature was used to assist braking.

 

[chorky]

In all your posts, and your original saga on the replacement, this is the first time you have mentioned that you regularly subject your automatic transmission to this type of abuse.

But why would that be considered abuse? I guess maybe if your downshifting at speed and the engine takes a huge jump in RMP as a result - but I use the manual option all the time when off highway to regulate RPM/MPH. Never even occurred to me that it would be considered abuse?

 

[Maximus Gladius]

Well, I pulled out my book and it definitely doesn’t mention using this feature is considered abuse. In fact, if the system detects the rpm’s would be too high by shifting, it won’t do it.

We are also very proud of being able to drive it hard and take those RPM’s up past 5000 - 6000 rpm with no problems. We say the 3.6 shines at these levels. Well if the engine is going there, it’s taking the transmission with it too. Is that abuse?

This term is Bill’s. It’s not in the book how I was driving.

 

[Mr._Bill]

The manual option is intended to give you more control in towing and other non-typical driving conditions. To regularly use it as a braking mechanism during normal driving I consider to be abusive behavior. Maybe it's not, but I think it's really hard on the transmission internals to drop it into a lower gear at higher speed and expect it to do the job the brakes are meant for.

 

[Maximus Gladius]

The manual option is intended to give you more control in towing and other non-typical driving conditions. To regularly use it as a braking mechanism during normal driving I consider to be abusive behavior. Maybe it's not, but I think it's really hard on the transmission internals to drop it into a lower gear at higher speed and expect it to do the job the brakes are meant for.

I used it to assist in braking. My vehicles before this one were manuals. I had always downshifted with the clutch while braking. That wasn’t abuse. You would probably write the book differently but for now the authors don’t care if it’s used.

 

[NotSo Bright White]

If it is abuse, then I too am abusive. I have driven my 7.3 liter Ford diesel this way for almost 30 years. The owner’s manual even states upshift and downshift RPM’s. And driving fire trucks for over 30 years, you would not consider going down a grade without downshifting or you would not have any brakes left to stop.

 

[IPRoutes]

The worst abuse that can be put on automatic transmission is shifting gears while backing out in reverse and shifting it to D while the vehicle has not completely stopped. Or vice versa. I see a lot of people do that.
Not saying the OP has that habit, but IMO statistically this bad driving habit probably is the biggest reason for AT failure.

 

[Maximus Gladius]

Not saying the OP has that habit, but IMO statistically this bad driving habit probably is the biggest reason for AT failure.

It was only used going forward and slowing down with the brakes.

 

[ShadowsPapa]

There's thousands of guys who modify automatics with manual valve bodies and shift completely manually - just without a clutch.
Think of those who have installed paddle steering wheels and the sport shifting of automatics.

All I can think of is you are downshifting too soon and putting a big drag on things.
Iron is going to be from the planetary gears for the most part.

To regularly use it as a braking mechanism during normal driving I consider to be abusive behavior.

Naw, not unless downshifting too soon at too high a road speed. Thousands of people have used the paddle shifters, or converting older automatics to a full manual valve body.

But why would that be considered abuse? I guess maybe if your downshifting at speed and the engine takes a huge jump in RMP as a result - but I use the manual option all the time when off highway to regulate RPM/MPH. Never even occurred to me that it would be considered abuse?

Only if shifting down too soon, or using it instead of braking.
You'd have to downshift and really feel it pull back to be abusive.
The TF998 has been turned into a racing transmission forever - manual valve bodies, hammering with 500Hp - so unless a person downshifts and really causes a hard drag on things, it shouldn't be a problem.
Iron indicates gears.

The problem comes in downshifting too soon, driving in too low a gear and then you have a sort of back and forth force on the planetaries.

But the transmission people out there even confirmed my belief - it's not bad unless you do it wrong (like I described above)
Using downshifts instead of braking is bad - but manually shifting isn't harmful. It's just when you drag the vehicle back too much by dropping down a gear before you really should.

There's a lot of info out there on it. You can shift if manually all you want - it's when you drop a gear and feel yourself moving forward in the seat - you are stressing things then.

Shift manually all you want - but temper how you do it. Manual shifting will not hurt the transmission.

 

[Mr._Bill]

I used it to assist in braking. My vehicles before this one were manuals. I had always downshifted with the clutch while braking. That wasn’t abuse. You would probably write the book differently but for now the authors don’t care if it’s used.

I did that too, when I was driving vehicles with a manual transmission. With the automatic, I let off the gas, use the brakes, and let the transmission do its job. I'm probably more careful than necessary with this transmission that is not intended to be serviced.

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