Shifted into reverse by accident (going forward) Help.

My son was driving my 1994 Jeep Grand Cherokee Laredo 5.2L AWD last night. He was traveling forward at about 40mph when he accidently knocked the shifter into neutral. He noticed his mistake when the engine reved so he let it return to "normal" and then shifted it into reverse instead of drive. The transmission obeyed, shifted into reverse causing a sever decelration. The tires did not skid but the engine quit and he coasted to a stop. He restarted the engine and immediately noticed the power steering was out.

I looked at the vehicle this morning and made the following observations.

The cast aluminum, triangular power steering pump bracket broke shearing the inner bolt. The tensioner appears to be bent and there is a slight bend in the tensioner bracket (I was able to bang this out easily). I believe the torque resulting from the transmission going into reverse at speed caused the engine to rotate excessively in its motor mounts where mechanical interference may have caused the powersteering bracket to break. I've yet to find evidence of an impact but I can't imagine what else would have broken it.

I also noticed this morning that there is a crack in the lower center portion of the windshield. This implies that the frame was twisted too as a result of the torque.

So, a few questions:

1). What inspection procedure should I follow to identify other areas of the vehicle that could be damaged? - some ideas are: - spider gears in front and rear diff for missing teeth - motor mounts for possible tear

2) Could the frame have been bent as a result of the? Should I get the frame inspected, if so where would I have this done? It seems that this is a rare scenario and not many would have experience with what to look for.

3) What possible problems might result in the transmission? Axle shafts? Other drivetrain component?

4) One mechanic suggested this might qualify for a comprehensive insurance claim, Is that true?

Thanks in advance, re5513

Reply to
re5513
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I have a question ... were you in the jeep when this happened? On another vehicle, I once accidentally tried the same manouver and the transmission did not shift into reverse ... it just did nothing until I got back into drive ... hmm ... good design work I thought at the time. So from personal experience I find it suprising the shift into reverse happened. But then we're talking jeep here :-)

Reply to
bowgus

Ya, I am having problems with the damage description too and I am a Jeeper....

My first impression was the Jeep was airborne and the shifter got knocked on the first or second landing bounce....

I would figure at least one engine mount tore allowing the PS pump to hit something and break. Man it takes some 'serious' shear to cut bolts or bend parts, 'No freaking way' torque did that, that had to be impact. same goes for frame flex enough to crack the windshield.

Jeeps have a 'really' strong full frame under with the body welded to the top of the frame on the Cherokees. I 'think' the Grand is the same, just go look, if you see frame rails, it is the same... They call them 'unitized' or 'uniframe' bodies and are real strong and flexible at the same time.

If the frame twisted enough to crack the windshield, wellll.... It 'sure' wasn't due to locking the 2 wheels up or the engine turning backward.... *(if you have lockers or limited slip front and rear, 4 wheels could have locked, but the same statement stands)

I would ask the 'little shit' just how far he flew before touchdown when he isn't expecting the question and watch how red he goes.... LOL! I have a 19 year old and he has only flipped my CJ7 on it's side once.... I was there in the passenger seat. He gave a 6 point turn on a 55+ deg down hill to up hill 'Y' intersection, glass ice trail too much gas on the 3rd turn and we slid off the side of the trail and flipped on his side. The look on his face was priceless! It was even better when he realized I was laughing my ass off. No damage, there was 3' of snow off the side.

I have flipped it too in snow and 'he' was the passenger....

Kids, including me when I was young, seem to have a lead foot eh....

Meanwhile, you seem to have a good idea on what to check, 'if' it was a reverse issue and not a hard bounce issue....

Good time to get the kid acquainted with tools in my book....

Buy the Haynes or Chilton manual for it and have him pull the diff covers to check them and change the fluid and have him check and if possible grease all the u-joints while he is under there.

Go for a 4 wheel alignment, if it is bent enough to need a 4 wheel setup and if it is out of spec for one, then yes, it is a 'write off' or an insurance claim that if fixed will never be a good handling vehicle again...

You are 'so' describing a 'really' hard bounce issue....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

bowgus wrote:

Reply to
Mike Romain

I agree 100%, that story about bumping the shifter is pure BS. I'm almost positive that the tranny in a 94 Jeep won't actually go into reverse at any kind of speed, even if it did it wouldn't cause that kind of damage. Bob

Reply to
Bob

No, I was not in the vehicle.

A Lot of the rice burners do not allow this by design. The Jeep GC has an A518 tranny which has been used in mopar pickups over the years. I also held the opinion that this was not possible (as in trying to shift into park at speed). My brother is a master ASE tech and he had no problem with the scenario predicting a high liklihood of motor mount failure. Like you, I am not even half convinced that the whole story has been told. No underside evidence yet found of off road or bottoming shenanigans. The kid was on his way back from work with a coworker so his schedule/routine is easily verifiable.

Accidentally shifting into reverse while going forward while uncommon does happen. In cases where the tranny actually shifts into reverse, the engine always is killed though some have been quick enoug to realize their mistake and get it back into drive and to keep going. In 2WD vehicles the tires often skid. I've not yet found another report of a 4WD or AWD vehicle put into this situation.

re5513

Reply to
re5513

Sorry, you're wrong. There is nothing mechanical or hydraulic to prevent engaging Reverse in a RH Torqueflight at any forward speed. The pre'66 Torqueflight, that was operated by an internal cable hookup, had a Reverse lockout, none after that did. John

Reply to
John Kunkel

touchdown when

reverse at

damage.

Many years ago when my friends and I were adolescently insane we used to shift into reverse at speed just for the hell of it. If you kept the rpm's up the back tires would start burning and you could loop the car around like an e-brake turn. Sometimes it wouldn't go perfectly and you'd end up in the ditch. These were rear-wheel drive cars, of course.

Ken

Reply to
Napalm Heart

A 94 Jeeps tranny is controlled by a transmission control module and I seriously doubt that it would allow a shift into reverse at speed. I do admit I have never tried it since I don't own a Jeep and would never subject a customers vehicle to such potential abuse. Let me ask you this: Do you believe the kids story, or is he trying to cover his ass for some more serious abuse?

Reply to
Bob

My guess would be the sudden lurch more than twisting. Like jumping off a curb or something. I would suspect something else happened to the vehicle he's not telling you about as it seems like a lot of damage. Another thing would be something like running over one of those parking "bricks" they put in parking spaces.

The damage sounds like running into something with the front wheels at too high a speed to be honest.

My friend did the same thing years ago in his Chevy Luv and it did squat to the truck. Shredded the syncros and tranny, but nothing else. Literally half of the transmission on the road, but the truck fixed up just fine.

Likely not if it is a real frame. Unibody is another story.

Any and all of it. Good auto shop/mechanic should look at it. Tell them you have no insurance and not a lot of money - and just want it to work. That should keep the padding down a bit.

Reply to
Joseph Oberlander

Good to see they are learning from their past designs :).

Reply to
Joseph Oberlander

Another option would be throwing it into 4-low at 40mph.

Now I *know* that doing that is possible and would mess up the drivetrain pretty badly. It also seems far more likely an occurance. Bump the wrong lever and suddenly everything comes to a very fast halt.

Check with a Jeep technician and ask about this control module. Then if it won't allow that type of behavior, inform your son of the fact and get the real story(cause something smells a bit off).

Reply to
Joseph Oberlander

Giving your son the benefit of the doubt and putting aside my suspicions of alternative explanations.... :-)

The A-518 might go into reverse at any speed, I've never tested one ti find out. Its just an A-727 with an overdrive unit added, and being a fully-hydraulic transmission its not designed with a bunch of idiot proofing (its been in production since 1957, but mechanical idiocy is a lot more common now than in '57). That being said, it might not go into reverse at speeds over, say, 15 mph because you can monitor governor pressure and lock out any gear.

If it DID go into reverse:

1) the weakest link is the reverse band. If it survived, then you probably didn't break any rear-end gears, any motor mounts, or anything like that. If it didn't survive, then you woudln't have reverse gear right now, so it would be obvious.

2) the PS pump tensioner may have been broken by the "slack" side of the belt suddenly being turned into the "tension" side by the sudden reversal of the engine. I see no need for the engine mounts to have shifted in order to break the tensioner and maybe the PS mount, but you SHOULD check the mounts just to be safe.

3) When aircraft engines experience similar things (propellors striking concrete, for example) a complete tear-down is usually required, and quite often micro-cracks are found in connecting rods and crankshafts. But being that this is a 318, it'll probably survive even if its life is shortened somewhat. Micro-cracking of a 318 crank isn't always fatal because its so lightly loaded relative to its overall size and ruggedness.

4) Cracked windshield? Nuh-uh. That points to "something else" besides just bumping it into reverse.

I guess my advice would be to fix the little things and then drive it with intense suspicion for a little while. Anything else that's going to die as a result of that event would probably do so within a few thousand miles at most.

Reply to
Steve

IIRC, the A-518 transmission (he said this is a 5.2L Jeep, not a 4.0) didn't get a TCM until around 1998. Prior to that, the engine computer controlled torque convertor lockup and O/D engagement, but reverse and gears 1-3 were controlled EXACTLY the same way as they are in a '66-up A-727 (because the front 2/3 of the transmission IS a '66-up A-727).

Reply to
Steve

Update: I located a new PS pump bracket from the dealer and installed it on monday along with a new tensioner. I had a slight problem with the alternator on monday night and sheared off one of the small bolts that connect to the alternator charge sensing circuit. I disassembled the alternator enough to fit it with a new stud but had to wait til tuesday to find an appropriate nut. Last night I buttoned up the whole thing and went for a ride. The bottom line is it seems to work OK so far. It shifts, goes into reverse, has 4WLo both forward and reverse, OD locks up and unlocks automatically and via the manual OD lockout switch.

The only significant hiccup so far is that the PS pump pully seems to be about .250" closer to the block (based on belt wear patterns on the idler pulley). The net of this is that the serpentine belt rides too close to the block and rubs. The PS pump pulley itself runs too close to a 1/2" pipe coming off of the block and interferes slightly. The obvious answer would seem to be that the new PS pump bracket is thinner than the old one. Maybe, but I did a visual inspection and it looked pretty close if not identical in thickness to the old broken casting. The design of the bracket though has changed with the new one semmingly less prone to cantilever stress related to where they put the major mass of the casting (center versus block side). After a brief call to my brother (ASE Mechanic), he felt maybe a shim of sorts would be a quick fix to get the thing back on the road. It could be that the pulley seated itself further onto the shaft of the pump as a result of the bracket failure. I'm going to pull the pump and bracket later this week and look at them both more closely.

Great advice. I appreciate everyones' responses. I'll be doing more later this week as work permits.

re5513

Reply to
re5513

I should have said, "... drive it with intense suspicion AND A CELL PHONE HANDY..." :-)

Glad it seems to have survived. Keep an eye on it.

Reply to
Steve

Approximately 8/14/03 11:50, Steve uttered for posterity:

And a chase vehicle... or a small ATV stuck in the back.

Reply to
Lon Stowell

Update #2: Saturday my son arose at 7AM and spent a few hours on the Jeep as per the suggestion of some. I had him replace the oil in the front and rear diffs. The rear was pretty dirty and probably needed to be changed anyway. What's with the Dana diff plug being a rubber stopper??? If found this odd since the front plug is a conventional threaded plug. I can't help but believe that simple rubber stopper leaks both ways without some help and attention. The front was still pretty clean. Neither front nor rear had metal of substance. I also had him do a flush/fill/filter on the tranny. Aside from the usual fine metal buildup in the pan there were no chunks or pieces. The glass guy thought the crack was from an impact but no one's talking or remembers a stone hit. It could have been there for a while and it just grew when the vehicle decelerated. The alignment came out as follows which seems OK.

L R - - Caster 6.8 6.3 Camber 0.0 -0.2 Toe 1/16 1/16

So far so good, 1 week and I've yet to have to call a tow truck :).

re5513

Reply to
re5513

I've also had a cracked windshield on a rear impact. The crack was on the opposite side as the impact. My car was parked on the street and a woman was looking over her shoulder at her kid in the backseat and ran into my car. It hit it so hard, my car bounced up onto the curb.

The bitch of it was, I had just spent over $300 on a new windshield (1985 dollars) because my car ('76 Caprice Classic) had the radio antenna inside the windshield. If I had just waited a few more months....

Tony

Reply to
Tony

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