Transmission Slam Issue…Nov. 15th, 2016 – April 2018

After purchasing the Saturn back in June of ’16, I noticed an occasional slam when the car upshifted. From 2nd to 3rd, and sometimes even 3rd to 4th. Not very often though. And sometimes when I’d start the car and shift into R I’d get a slight slam. I learned to take my foot off the fuel pedal when I’d put it into R so that didn’t happen often. Did some reading and found that this is called a Reverse Slam. There’s a bit of confusion because of the name since it covers a plethora of issues not always related to shifting into reverse so I’ll just call it the Tranni Slam or just Slam.

The slam was fairly mild in the first 5 months I drove it while racking up 3,000 miles. So I didn’t really worry about it. And then, a few days before I did the Intake Manifold Gasket job, it started slamming all the time. And instead of the slam being occasionally, it changed to just having a ‘normal’ shift occurring occasionally. Not happy about that. Some of the slams caused the car to shudder too. That was new to me.

Went ahead and did the gasket job hoping that having the battery disconnected would clear the computer and improve the slam situation. Just the opposite. It was worse. So, went back to do more reading and decided to do the ‘Reverse Slam Cure’ by Wolfman.

What was obvious back in ’03 when that was written, isn’t so obvious in ’16. Finding ‘conventional’ ATF wasn’t easy as many auto part stores only carry synthetic these days. But, whatever, I found the oil and filter at Napa. And I bought the suggested Prolong online at Amazon because NONE of the area auto parts stores carry it and I wanted to use the product recommended by Wolfman.

Than I had to find a video of how to access the tranni filter in a Saturn. The filter can’t be removed from underneath the car I guess and you have to remove a bunch of stuff from the engine compartment to get to it. Which is OK because that allows inspecting, cleaning, and perhaps testing the electrical connection on top of the transmission. (I forgot to bring my informational sheet of which pins are which so I couldn’t do that this time.)

Here’s the things that have to be removed:

1. Remove the plastic air intake assembly from the air filter box and the throttle body intake, by loosening 1 clamp screw, also remove attached hose;
2. remove the air filter box, two bolts, sometimes corroded and needing some PB Blaster;
3. remove associated air filter box assembly that’s attached to the middle of the radiator, 1 snap in plastic clip;
4. remove battery clamp, 2 bolts, 1 nut;
5. remove battery, 2 side bolts;
6. remove the battery holder, 3 bolts, almost always rusted and corroded, where one of the bolts, more like a long screw, comes in from the wheel well but can be reached with long extension w/o removing the tire.

Here’s a pic of the battery clamp bar, battery, air filter manifold and pipe, all which need to be removed. The fuse and relay center can be left in position.

This is an additional air box that’s loosely connected to the air filter box with a plastic pipe. The push pin there in the middle of the box holding it to the cross piece is pried up and pulled out, than the entire box is lifted up and away from the cross member, which detaches the plastic pipe going into the air filter box. No clamp or anything holds it there. 

At this point you have access to the tranni filter which is under the air filter box, the tranni electrical connector on the top of the tranni, and if you’ve a mind to, the top cover bolts that allow you to remove and replace, or work on, the tranni control, named the ‘Valve Body’. It has 5 solenoids inside. Note that removing the cover requires that the master brake cylinder is loosened and moved a little out of the way.

There’s some tests you can do here, but I continued on with the procedure to drain the ATF, replace the oil filter, and adding conventional ATF. As preventative maintenance and to visually inspect the contacts, I did remove the electrical connector and used contact cleaner spray on the contacts.

Reverse Slam (Tranni Slam) Repair Procedure:

1. Set the parking brake, jamb chocks in front & back of the passenger side drive wheel and driver’s side rear wheel to prevent movement;
2. jack up and place a jack stand under the drivers side, remove the tranni drain plug, draining the tranni of approximately 4.2 qts;
3. inspect the drain plug washer for damage, clean and replace the oil drain plug;
4. remove the tranni filter from the front of the tranni;
5. remove the magnet, if present, from the business end of the filter, clean and attach to the new filter (experts tell me you’re suppose to throw the magnet away after the 30K mile oil change);
6. reinstall new filter;
7. add Prolong 8oz, and 4 qts oil (see below for amounts in other situations);
8. drop car to ground, make sure brake is set and tires still chocked;
9. start car, check for leaks, and that parking brake is set strongly, than shift into reverse;
10. run car in reverse 20-30 minutes with hood open. This will not harm the car in any way. Do not leave the car unattended.
11. Allow tranni to cool. Done. Road test.
12. Drain out dino oil and replace filter at the next regular tranni service, replace oil with synthetic.

There are three ways of draining the oil, one which drains out 4.2 qts, another which drains out 5.5 qts. And finally, a rebuild which loses 7.5 qts.

1. Remove drain plug and drain. Replace and tighten drain plug. Remove tranni filter and dump into pan. Put on new filter. Amt removed = 4.2 qts
2. Remove drain plug, then remove tranni filter. Let drain. Amt removed = 5.5 qts.
3. Take the tranni out of the car, then pull apart. Amt spilled = 7.5 qts.

I did oil drain procedure #1. I had high hopes for the tranni slam repair procedure as my symptoms were mild up until a week ago. But, alas, no, the symptoms have been worse since I did this job. There’s a slim possibility that the computer just hasn’t adapted yet to the computer being unplugged for so long, but that doesn’t seem likely.

More to come…

On Edit: Nov. 22, 2016

I’ve still been experiencing the tranni slam but have discovered that if I am careful, accelerate slowly from a stop, that I can minimize or eliminate the slam in 2nd, 3rd, & 4th. Usually it over revs just before shifting into 3rd and if I let off the accelerator when it does, it quietly shifts into 3rd.

If I need to accelerate quickly, I’ve found that it will almost always slam. So I try to avoid that. It’s difficult here in Southern California with everyone driving like a teenager but so far so good. No gunshots yet. I printed out a nice big sign for the back window:

SLOW DURING

ACCELERATION

IT

CAN’T BE HELPED,

WORKING ON

TRANSMISSION.

So that should prevent people from getting too angry anyway. Before I put up the sign, I’ve had them get right up on my tail driving aggressively as I’m trying to get going on a 4 lane arterial and I’m boxed in by traffic.  Dumb ass drivers down here. My brother is one of them. They’re nuts, and everyone is in a hurry in SoCal. Since the sign, I’ve had a noticeable number of people thank me, give me a thumbs up, or be less aggressive when they see it.

UPDATE: DEC. 10th, ’16

While driving around here in the Imperial Valley, I was experiencing quite a few ‘slams’ as the car upshifted from a stop. Gears mostly involved were 2nd and 4th with 3rd occasionally doing it too. That hard slam can’t be good for the car and it really bothers me so I was considering taking it to a shop. But then 4 days ago, I was on a long shopping trip looking for plumbing parts for my RV and the slams were particularly harsh. And in stop and go traffic, unavoidably often, even when I feathered the accelerator. UNTIL I realized that, hey, I can do the shifting where I want instead of having the computer do it. So at the next stop light, I downshifted into 2nd gear. When the light changed, I accelerated up to 25 MPH, removed my foot from the accelerator, and then manually shifted up to 3rd. And it slipped into 3rd nice and smooth. Not a bit of hesitation, no unusual change in RPM, and not even a minor slam. Then accelerated up to 45 MPH before shifting into D. Again, smooth.

So that’s what I’ve been doing since. Driving the car like it’s a manual tranni without a clutch. A new habit is forming and I’m rapidly getting use to shifting that way. And it has worked every time. No slam at all over four days and a couple hundred miles of driving (I took a tour yesterday and traveled 120 miles around the Salton Sea as a test of the tranni).

What this method does is give me time to enjoy my RV traveling, without having to worry about the tranni on the car going bad simply because the slam damages it. I don’t know if it would in my case, other than the experts say that to many slams can cause the shaft nut to get loose, and if that happens, the tranni will be ruined if it’s driven too far. But with this way of gentling the slam, I can pick and choose when I want to work on it.

Update: March 2017

Using the method of minimizing the tranni slam as noted above worked well with just a few times where I’d forget to upshift or downshift. Worked particularly well in San Felipe, Mexico because the town’s roads are in such bad condition, I’d be able to drive all over town in 2nd gear and never get above 25 MPH. And then one Saturday, I went north of town and waited for a friend to join me so we could go to the Blues Festival. Unfortunately, she thought I meant Sunday, so I sat there waiting with the Saturn idling and the AC on. After an hour of that, when I left the parking lot, I found that it would now slam hard, even though I was using my upshifting method and shift points of 25 MPH and 45 MPH. Nothing I tried differently helped. So, I just did my best to not drive in the 2 weeks I had left staying in Mexico. My plan was to work on it when I got back to the US on March 27th.

Update: April 2017

Did my best to minimize my car trips after arriving here at Gila Bend, Arizona to avoid the slam and was successful for the most part. I did have an empty refer, and my pantry was fairly thin looking too so I did have to make a couple shopping trips. Once I had a few days worth of food, I got right to testing the transmission. And to do that, I needed to pull those engine compartment parts mentioned in text above when I did the filter and oil change.

The air filter assembly is removed first…

This air overflow box is then removed…pull up on the push pin and it pulls out, which releases the box from the radiator cover, then the box can be gently pulled out of the air filter box.Than the battery is removed, followed by removing the cables from their snap clamps which allows moving the bundles of wires or cables out of the way.And here’s the snap on connector that goes to the air flow sensor that’s integral to the air filter box pipe. Wanna make sure you get that unplugged so you don’t pull on it too much. I used a long pair of needle nose pliers. Squeeze the sides a little and the connector pulls right off.I followed this youtube video for most of this work: Changing Tranni Solenoids.

After most of the plastic pieces are removed, then the battery tray is removed. There are two obvious bolts in the bottom of the tray, and then a not so obvious long bolt accessed through the driver’s side wheel well. With those three bolts removed, and the electrical bundles detached, the battery box is pulled out and you can see the top of the tranni. I pulled the AC hose and electrical cable up and lashed them out of the way. Then the tranni solenoid electrical connector bolt is unscrewed and the connector can be pried off the tranni cover and its mating connector. At this point, using a digital ohmmeter, measure the resistances of the tranni solenoids, they should all be in the range of 4.5 to 6.0 ohms and here were my readings:

A-B 3rd gear: 5.2 ohms; C-D 4th gear: 5.4 ohms; E-K TCC: 5.3 ohms; F-G Line: 2.0 ohms; J-H 2nd gear: 5.5 ohms.

And here’s a drawing I made up afterwards to help with the testing and identifying solenoids:

So, the line solenoid is bad and needs to be replaced as it only read 2.0 ohms. The line solenoid works the hardest out of all the solenoids at maintaining the line pressure. Went ahead and ordered that online, cost was around $70. Than using a brush and my shop vac, cleaned the area where the cover edge is so none of the grit there will end up inside the tranni when I work on it again. My engine has few oil leaks so cleaning it was fairly easy using a vacuum.

Replaced everything temporarily while waiting 3 days for the part. When that arrived, quickly pulled everything back out and got to work. This time, also loosened the two bolts holding the master brake cylinder and the single bolt holding the ABS manifold. This gives an inch of freeplay which allows the top of the tranni case to be removed a little easier.

Cover bolts for the first protective cover are all the same style and length so as I loosened them, I’d pull them out with my magnet and put them in the magnetic automotive tray I have. After they were all removed, thumped the cover a couple times with a rubber mallet, pried on it a bit with a flat blade screwdriver and removed it. Cleaned the machined surface where the cover gasket goes. The gasket looked fine, didn’t see a need to replace it, the mating surfaces did need cleaning though.

Than it was time to remove the solenoid cover, which is under the 1st cover. Despite the relief I got by loosening the ABS manifold, still had to do some gyrations to get at all the cover bolts. Luckily, they aren’t very tight so smaller tools are usable.

As I removed those bolts from the 2nd cover, the cover that protects the solenoids and electrical area, I jabbed them into holes I’d made in a piece of cardboard where I’d drawn an outline of the cover. I left the two shown still in the cover, after they were loose.After that cover is removed, there’s another plastic cover over the solenoids that has electrical push connections that mate to the two terminals on the tops of each solenoid. No tool needed to remove other than hands gently pulling straight up. The solenoids than need to be twisted a bit, and then pulled straight out to remove.

From left to right, the coils are 1-2-3-4-5 with #5 being the one furthest right and lower than the others in this picture. At this point I remeasured their resistances again and the #1 was still 2.0 while the rest are still within tolerances so I removed and replaced #1 with the new coil. It measures 5.4 ohms. I just twisted and tugged straight up on the coil to remove it by hand, no tool needed. It came off easily.

Here’s how I supported the master cylinder and ABS manifold while working on the tranni. The cylinder doesn’t need to be removed, just loose so it wobbles out of the way a bit.

After the bad solenoid was replaced, it was just a matter of reversing the procedure to get the covers back on. The top cover bolts I held with a magnet tool as I helped align them with the bolt holes before tightening. Didn’t lose a one. That black rectangle on the cover is the electrical connector. You can see how easy it would be to measure the resistances of the coils there.
After the tranni covers where back on, jacked the drivers side of the car up a foot, put a pan under there and drained out the old dino oil. Removed and replaced the old filter with new. Removed the magnet from the filter I’d left in there before I’d done the ‘Reverse Slam Cure’ mentioned earlier. Added 4 quarts of synthetic ATF. Replaced all the removed parts, reconnected the electrical, and we’re done. Not worried about mixing the synthetic oil with the dino oil. It’s fine for that. The job took 3.5 hours at a relaxed pace, not counting the hour I used to get in there and measure the coils so I’d know how many to order.

Testing Apr. 4th, ’17:

I immediately drove the car after replacing the line pressure solenoid. With new filter, and new tranni oil, and most of the symptoms were gone. Shifting into reverse first to back out of the space, it smoothly slipped into gear with no delay. After backing, I shifted into drive directly…instead of my usual procedure of shifting into 2nd, accelerating to 25 and then shifting into 3rd, then drive. And I get a thump as it automatically upshifts from 2nd to 3rd. It’s not suppose to do that. From 3rd on, the shifts are nice and smooth. No over revving of the engine.  Much different than the symptoms I had before replacing the solenoid. Much better performance. But not fixed. Gah!

Since the battery was disconnected for so long, my forum reading has told me that it’ll take around 50 miles of driving for the computer to relearn the shift patterns, and I think that’s been accomplished after the 140 miles I’ve put on it since the solenoid replacement. Whether or not that’s made any difference I’m not positive but it does seem to shift nicely at the correct RPM points into 3rd and 4th. And when downshifting too. It’s just when it up or downshifts into 2nd that it thumps.

Unfortunately, I can’t find an explanation online of what my symptoms indicate. I have found a nice work around though. If I remember to do it.

If I am accelerating from a stop, I start with the shifter in 2nd and just upshift from 2nd to Drive after I reach the 15 to 20 MPH range. When slowing, I downshift into 2nd after I’ve slowed to less than 20 MPH. Each of these actions guarantee a smooth shift transition. If I forget either one of these actions, I get a thump. Sometimes conditions are such that the thump is more of a slam, and that’s not good at all, luckily it’s rare. All the other shift points are smooth.

In any event, I have this workaround for now and I’ll stick to it until I learn what might be causing the 2nd gear thump.

One obvious benefit to changing the solenoid was that before, my around town shifting caused a decrease in mileage to 24 MPG, because it’s difficult to consistently hit the right point to upshift. After the solenoid change, and only upshifting from 2nd to D from a standing start around a speed of 20 MPH, the automatic is taking care of the shift points properly after that more of the time than I did so my mileage has jumped up to 26-30 MPG. And that’s with occasional AC usage.

More News-April 20th, ’17:

After I got use to upshifting from 2 to D to prevent the mild thump I was getting from the tranni, it was time to get back on the road and head north to cooler climes. So I headed for Beatty, Nevada. A little town with little going for it but that it’s at 3300 feet so tends to be cooler. Oh, and it has a great little bar with excellent chili!

That longer than normal trip…8 hours…seemed to deplete my car battery because when I tried starting it after towing it all those 440 miles, all I got was a clicking sound from the starting solenoid. So I connected my charger, got it started and drove a few miles to let the alternator complete the charging. The next couple trips (it was back to starting normally) I still would start out from a stop in 2nd, then at between 15-20 MPH I’d upshift to D to minimize the thump. When decelerating, I’d downshift when I got to below 20 MPH. I didn’t notice anything different.

And then the inevitable happened…I forgot to put it in 2nd at a stop sign, inadvertently left it in D. And when I accelerated, no thump. Huh. So I tried it several more times…still no thump. And no thump when decelerating either. Well, this is looking better. It seemed to be fixed! So I kept driving like a normal AT is suppose to be driven, with the gear shift in D.

And after having driven it over 100 miles since, I’ve found that it does not thump at all any more. It cured itself. What I guess happened is that there’s a bug in the firmware that controls the tranni shift points that was causing the thump, and when the battery dropped down to 10.8 volts, it reset something so that it shifts properly.

I now consider the tranni fixed.

Update – July ’17:

The tranni performed better and better after leaving Beatty.  The slam and/or thump is completely gone, and the shift points when accelerating moved into the correct places. I now always shift directly into drive when accelerating from a standing stop and always leave it in drive. It seems as though the computers tranni ‘Learn’ process takes a little longer than most forum posts I’ve read would suggest. I also determined the battery had died so I replaced it.

Update – March ’18

And now I don’t even think about the tranni most of the time. I do naturally downshift to reduce the necessary braking to extend the brake pad life, but generally, I just drive this automatic tranni like a normal driver. And it is always nice and smooth no matter how much stress I apply. Never a clunk. So I guess that’s telling me that the computer needed to relearn after all those years of that bad solenoid being in place. Now that it’s learned it, it’s smooth as silk.