Car transmission ?

[David Ragan]

Is it hard on a car transmission to put it in drive while car rolling in reverse, w/o coming to complete stop?

[Ken Fitzgerald]

Manual or automatic transmission?

[Ken Fitzgerald]

Your car or mine?:eek::D

[Bruce Page]

It's not good for the transmission or the axle housing.

[David Ragan]

Auto. My wife and i always come to a stop
my BF-brilliant USAF mechanic says no big deal (perhaps cause he can fix himself)

[Kent A Bathurst]

Guys, guys, guys.......Buncha sissies............:p

Getcha a solid, German-engineered, manual tranny..........a little roll back when you pop the clutch simply lets you leave more tire on the road as you launch.

Don't slip the clutch - let it pop as you slam down your right foot.

You're good for 200k miles and counting.........Tires go a bit quicker, tho.:D

[Steve Peterson]

It is never good to force something to go a different direction than it is already going. The damage is going to be proportional to the severity of the change in direction.

I am assuming that you are talking about an automatic transmission.

It would be pretty hard on the transmission (and drive shaft and tires) if you slam it into reverse at highway speeds. The torque converter may still provide a level of protection and the car may still run just fine as long as you only do it once or twice.

If you are going forward 5mph and shift into reverse at 5mph, then it is probably about the same stress on the driveline as quickly accelerating from 0mph to 10mph. In other words, there is minimal risk.

If you are rocking your car out of a snow bank, then the forces are fairly small. The car has no momentum other than the small mass of the spinning tires.

Steve

[Bob Turkovich]

Auto. My wife and i always come to a stop
my BF-brilliant USAF mechanic says no big deal (perhaps cause he can fix himself)


Driving a little early after that knee surgery, huh, David?:p

Depends on how fast you were going in reverse. Need a few more specifics (Speed, FWD/RWD/AWD, vehicle brand & type, fully loaded or only one or 2 pass. etc.) For most vehicles, if it's a one-time event you should have no problems with it.


Guys, guys, guys.......Buncha sissies............:p

Getcha a solid, German-engineered, manual tranny..........a little roll back when you pop the clutch simply lets you leave more tire on the road as you launch.

Don't slip the clutch - let it pop as you slam down your right foot.

You're good for 200k miles and counting.........Tires go a bit quicker, tho.:D

This coming from the same guy who started a thread pooh-poohing elitist tool purchases...:D

Kent, let me tell you a couple of German Engineering stories. Years ago I had a Dodge Omni with the A-412 manual tranny. It was purchased from VW and was the exact transmission used in the VW Rabbit. I had to repair the tranny twice in 60K miles for the exact maneuver we're talking about. Each failure was after one occurence. Tooth would break off the ring gear. That, in itself, wouldn't be so bad but the path the broken tooth would take would go into the differential and cause collateral damage. Car sounded like a tambourine in a garbage can.

The second story is more recent. Had the responsibility for adapting a Mercedes production driveline part into a Chrysler driveline. We started out using the identical part used by Mercedes - made by the same supplier on the same tooling and assembly line - and had been in production for a couple of years. Late in pre-production testing we developed a problem due to excessive wear. We asked Mercedes if they had seen the issue since their application was putting more load into the part than ours. Nope - no warranty issues at all. Couldn't figure it out. Finally we developed a revision that took care of the problem. Asked Mercedes again - nope, they don't have the problem. Asked if they were willing to accept the change anyway. Nope, cause it added cost to the part. As a result, the supplier then charged us even more for added complexity.

I had to go in front of the top management of the company and explain why we couldn't figure out why our application was failing the part. Couldn't explain it. Got my backside royally ripped for that. Got doubly ripped for the added cost. Management finally agreed to the change but had Engineering take the financial responsibility for it. The vehicle cost was tracked accordingly.

The week before the change went into production, the supplier stopped by. Good news! Mercedes went back and found they actually did have the problem in the field and now wanted to make the change as well. As a result, the cost for added complexity was being dropped and the cost of the change itself was reduced to pennies due to economies of scale.

Later on,to add insult to injury, Purchasing got credit from Finance for pulling the cost back out as a result of a "negotiated cost reduction.":mad:

So if your touting German Engineering, it better be Brand B.

[Jim Matthews]

There are so many things that can go wrong with this, where to begin?

"Bump" starting any clutched vehicle puts tremendous
instantaneous torque on the mating plates, followed by the
a lurching of the engine as it turns over.

For those of us that haven't been under a vehicle in a few years,
there's a lot less room to maneuver. My last car required
that the entire transaxle be dropped to get at the clutch housing.

My mechanic recommended removing the engine and tranny together,
to avoid damage to the mating bodies. He said they go in that way,
and should come out in the same manner.

Given that the spec on my current Triptronic transmission is $8k just for the rebuild,
I'll start when the vehicle is parked, thank you.

[Kent A Bathurst]

So if your touting German Engineering, it better be Brand B.

Dude. The Ultimate Driving Machine.

[Bob Turkovich]

Every OEM should have some type of rock cycle testing as part of its endurance testing. It should simulate a driver trying to rock their way out out of a stuck condition and then suddenly hitting dry pavement. For example:

Load vehicle to 95% GVWR and place on high coefficient friction surface. Set throttle to 30%. Place vehicle in R for x seconds. Without braking, shift into D for x seconds. Repeat 10 times. Come to stop for y minutes to allow transmission to cool down. Repeat this entire sequence 10 times (i.e, 100 total cycles).

I may not have the numbers exactly right (I've been fully retired since 2012 and I've never been good at remembering numbers) but every drivetrain at Chrysler for the last 30 years had to pass this type of test.

Re: My earlier comment about being vehicle specific. In the 10 years prior to my retirement, we used to annually run competitive vehicles side-by-side with ours thru endurance testing. Most - but not all -competitive OEM's could pass this type of test (and, no, I'm not saying who wouldn't.).

[David Ragan]

Now, that is some expert reply. Wow.

Thanks guys-everyone.

I was so glad when my wife got rid of her Benz. She has for the last few years, driven new ones-in warrantee. When this last one came out of warrantee and she had to pay for a simple oil change-$$$, she sold. Got a Honda Pilot-for her small stature-we call it The Bus.

[Chuck Wintle]

Is it hard on a car transmission to put it in drive while car rolling in reverse, w/o coming to complete stop?

my opinion is the car should be at a dead stop before shifting from reverse to drive. This will put much less strain on the drivetrain components such as the constant velocity joints for front wheel drive, the engine and transmission mounts, and the transmission internal parts.

[Larry Edgerton]

I like Kens line of reasoning, if it can't take it buy a better car. My wifes Mazaspeed3 suffers occasionally at my hands, and it loves it!

The new automatic will not let you do reverse slams, which is the proper term for such shinanigans. If you are rolling backwards it will just drop to idle until it is stopped, then move forward. My 2014 Ford 150 is this way as was my 09 Chevy Silverado

The thing I hate the most that totally messes with my need to occasionally be irresponsible is anti skid control. I need to get sideways once in a while!

Larry

[Phil Thien]

My wife had a Dodge Omni with an automatic when we met. I liked that car quite a bit.

A "friend" did a neutral drop in a parking lot and the transmission thudded badly when shifted thereafter.

He also screwed up my Honda (bike) when I told him to take it easy because the chain was a little loose and I needed to snug up the tensioner.

I come to pretty much a complete stop when changing directions. It isn't a perfect complete stop, but it is close enough to count.

[ken masoumi]

my opinion is the car should be at a dead stop before shifting from reverse to drive. This will put much less strain on the drivetrain components such as the constant velocity joints for front wheel drive, the engine and transmission mounts, and the transmission internal parts.
Absolutely right.
I would also add,a car would have less wear & tear in steering components,linkages,hydraulic pump.rack & pinion if in motion while steering rather than from a stock still/ motionless.

[Scott Ticknor]

Rentals, now there's a car that can go from forward to reverse at any speed. Company vehicles come a close second . ;)

[Myk Rian]

I let my truck roll slowly when I put it in drive. Keeps the U-joints from getting torqued on take-off.