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15yearsaturnguy, Saturn master tech
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Experience:  25 years automotive experience, 15 years with Saturn
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2001 Saturn: automatic transmission..intermittent slam shift behavior

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2001 Saturn SL (SL1? 1.9 litre engine) electronic automatic transmission fault codes showing up along with intermittent slam shift behavior: could this be as simple to solve as changing the shift solenoids? Need to change the valve body? Other things or sensors to check first? Or would the best advice be to change out the transmission for a rebuilt unit?

Saturn transmission codes:
PO732 Incorrect gear 2 ratio
P0333 Incorrect gear 3 ratio
P0766 Shift solenoid D performance or stuck off
P0783 3 to 4 shift problem
P0789 Shift timing solenoid intermittent

Is this a common fault of the S-series vehicles? Is there a serial number range or manufacturing date range or some such of S-Series transmissions that were known to have manufacturing/assembly faults? Any updates to the transmission that correct the problem when remanufactured/rebuilt? Any service bulletins that address this issue? If the best advice is to replace the transmission, what should I be looking for to get a reliable one?

On the latest occasion when it did a slam shift, it now refuses to shift down into 1st gear. I notice those times when it won't shift down that there's a faintly noticeable low-pitched whine to be heard when not moving and shifted into the forward gear positions.

There's never a problem in reverse, as I've seen in other posted complaints.

Some history/description:

Purchased the 2001 Saturn SL 1.9 L in November, 2011.

In early December drove the car 1 1/2 hour trip one way, parked the vehicle for about 1 1/2 hours. Came to time to leave, began to move the shift lever to drive and the engine roared and revved like a stock car racer about to take off from a standing start (the vehicle was not in motion). Rammed it into park and it quit revving and seemed to be ok after. Perhaps related to the intake manifold gasket issue? (see more below).

Around Christmas drove another 1 1/2 hour trip one way. On slowing for an intersection, there was a "bang". i.e. it seemed to be a bang, much like if one were braking on ice and suddenly you hit bare pavement and the wheels gripped. Except there was no ice. Seemed to be ok, and drove another quarter mile into town and parked. About a half hour into the return trip, on slowing down for a stop sign it did the "bang" again (slam shift). Stopped at the stop sign. Found it would not shift down into 1st gear. Let it labor at the take-off and carried on home. Car would not shift into first gear the rest of the trip home.

Took it to the shop in early January and wouldn't you know it wouldn't reproduce the problem; seemed to shift fine, but there were the fault codes. Had a trans-vac carried out to flush the transmission oil, changed the filter and refilled with Dexron III.

Had some rough idling show up, which I thought was spark plugs and/or wires. Rough idling showed up again. Took it back in where the problem was traced to a bad intake manifold gasket (folded and sucking air on one cylinder). Engine ran great after the gasket change. I don't think this would have any bearing on the transmission shift issue?

Still occasionally doing the slam-shift thing. Added half a can of "Sea-Foam" trans-tune treatment to the transmission. Noticed a marked improvement in the shifting pattern, especially the shift-up points seemed to be more normal and not so high as before. Did notice that on coasting to slow down for stop signs or turns at intersections that there was a fairly noticeable down-shift bump at about 60 kilometres per hour (just below the 40 mph point). Shifting seemed to be really good for quite a while, then periodically did the slam shift thing again.

As noted earlier, its most recent slam shift it again refuses to shift down into 1st gear. I notice according to the user manual that it says if the transmission is shifted into 2nd gear that it will NOT shift into first. It's almost as if the transmission is stuck in 2nd gear mode?

I notice those times when it won't shift down that there's a noticeable low-pitched whine to be heard when shifted into the forward gear positions.

Also noted that sometimes after it exhibited the won't-shift-into-1st behavior that sometimes it wanted to rev very high before shifting up (into 3rd?).

15yearsaturnguy :

Hello and thank you for your post. I am a master certified GM tech, with 15 years Saturn experience,and can help you to resolve your issue.

15yearsaturnguy :

this is a lot of info to digest

15yearsaturnguy :

the thing to know about these transmissions is that all or almost all of the issues we see are either due to a bad valve body, a bad connection at the valve body, a loose input shaft nut or a bad prndl switch on the back of the trans

15yearsaturnguy :

the codes you deem to have tell me that you may have a bad connection at the valve body (inside the valve body under the cover)



15yearsaturnguy :

the solenoids are in teh valve body and occasionally the buss plate (black plastic connector plate) can get loose connections at the terminals where the solenoids snap in place

15yearsaturnguy :



What's a "prndl" switch?

15yearsaturnguy :

the transaxle range switch

15yearsaturnguy :

(neutral safety switch)

15yearsaturnguy :

we usually use a scan tool and make the solenoids "buzz" while wiggling the connector on top of the trans

15yearsaturnguy :

if the buzzing starts and stops when doing that then we know the connector is bad

15yearsaturnguy :

the loss of 1st gear combined with teh whine from teh trans tells me you probably have a loose input shaft nut


Re. transaxle switch - makes sense. What do you make of the fault codes?

15yearsaturnguy :

the codes all point to conditions related to the solenoid connections being loose


OK on loose nut.

15yearsaturnguy :

you may also have wiring issues leading to teh trans

15yearsaturnguy :

not so common in 2001 but can happen

15yearsaturnguy :

wires can be chewed by a rodent or rub on the a/c line or something


Solenoid connections is what it seems to suggest to me.


The tranmissions 'til now has acted solid except for the shift issue.

15yearsaturnguy :

without using my $3500 scan tool to diagnose this...based solely on your symptom...I would remove the end cover and replace the input shaft nut (if it's loose) and then remove the top cover, remove the bus plate and see if the connections are loose

15yearsaturnguy :

if they are, replace the bus plate

15yearsaturnguy :

if they are not, replace the entire valve body



15yearsaturnguy :

these issues affected every single S-series car regardless of year or engine type


I have a good mechanic, but I think he's concerned about spending a lot of time to diagnose and then still end up having to replace the transmission


OK on issues affecting all S-series.

15yearsaturnguy :

but the p0789 code didn't come around until 2000 and that is almost always teh bus plate


How likely is the slam shift to damage the transmission itself?


What about the incorrect ratio thing?

15yearsaturnguy :

as far as replacing the trans, it is rare for these trannies to fail but it can happen

15yearsaturnguy :

the slam shifting is usually what causes that nut to loosen up

15yearsaturnguy :

the incorrect ratio thing is caused by the shift solenoids


Going to call my mechanic and see if he has questions... Just a moment...

15yearsaturnguy :

they can also be caused by a bad pressure regulator in teh valve body so the vb may still be bad but if you have no reverse delay or bang then I doubt the regulator is bad

15yearsaturnguy :

it is part of teh valve body


OK. He says we need to check your suggestions before we go any farther.


What do I do now. I'll click accept and we'll come back if we have any more questions?

15yearsaturnguy :

ok. so do that and let me know how you make out

15yearsaturnguy :

if he has a scan tool that can buzz the actuators in the trans (solenoids) have him do that while wiggling the connector in teh top cover. not the connector that bolts to the cover, the plastic piece that pokes through the cover that the bolt on connector bolts to


OK. Thanks for now...


He has a scan tool, but don

15yearsaturnguy :

wiggling that will cause the buss plate to shift from side to side and can cause the buzzing to start and stop indicating a bad connection


....don't know if it can make them buzz. I'll check...

15yearsaturnguy :


15yearsaturnguy :

good luck



15yearsaturnguy :

my pleasure

15yearsaturnguy and 4 other Saturn Specialists are ready to help you

if you need me again you can post your info or question here even after you click accept.

thank you and good luck.

I am here if you need me

Customer: replied 4 years ago.

Long hiatus for various reasons but finally getting in to the transmission. Report on status:

Word from the mechanic this morning is that resistance reading on all five solenoids is within range of 4.8 to 5.2 ohms: 2nd=5.1, line pressure=5.2, TCC=4.9, 4th=5.0, 3rd=4.8. I believe those are measurements made through the connector with buss plate still on.

He says the input shaft nut is not loose.

Next to check the prndl switch.

Currently the transmission is stuck in 4th gear; it won't shift down into 1st.

Question that comes to my mind is how do I know the proper signal is getting to the solenoid in the first place?

Other than that, it looks rather like there is an issue in the valve body.

at idle all of the solenoids get 12v and the ground is pulsed on by the trans computer

this cannot easily be tested without a scan tool or lab scope

if you have 12 v at pins J, E, A, C and G then the powers are ok

if it is stuck in 4th gear, be sure the battery voltage is above 12.6

a bad alternator can cause the stuck in 4th gear symptom if battery voltage is too low

otherwise, I would think the valve body is bad

of course any codes stored will lead us to what needs to be checked. are there any codes?

if you have a p0731, p0732, and p0733 then the vb is most likely bad


Customer: replied 4 years ago.
Yes, there are codes, noted at the top of the original post, Namely:

Saturn transmission codes:
PO732 Incorrect gear 2 ratio
P0333 Incorrect gear 3 ratio
P0766 Shift solenoid D performance or stuck off
P0783 3 to 4 shift problem
P0789 Shift timing solenoid intermittent

These were recorded back in April or earlier of 2012 and it has not been driven since then.

Thanks for your help. Will see what mechanic says at day's end. Am sending him a copy of your suggestions.

and replacing the valve body will cure both a bad connection at the buss plate as well as a faulty valve in the vb assembly so either way the valve body will fix this unless the computer is bad which is unlikely

I'd be pretty certain of a valve body on this one


Customer: replied 4 years ago.

Re. 2001 Saturn SL (SL1? 1.9 litre engine) electronic automatic transmission fault codes showing up along with intermittent slam shift behavior:

Mechanic has had valve body and buss plate out. Buss plate is good. Took valve body apart and one valve a bit scuffed, which he polished and replaced. Other than that no problems evident with the valve body. The valve body has been replaced relatively recently. It's a Trans-Tech valve body. That explains why the buss plate looks good. Transmission oil is very clean (mechanic was impressed). So somebody has done a lot of work on this transmission for that very problem and evidently didn't solve it.

The PRNDL switch was working when he took it apart. But perhaps it is intermittent? Will check it again.

Wiring didn't show any evidence of rodent or other damage, but need to check the wiring harness again.

Assuming PRNDL and wiring pass repeat check, now what? Could be an issue with the PCM (power control module)? How to test/verify that? Perhaps some funny interaction from the BCM? Computer has corrupt firmware? Are you aware of any firmware updates (Can it be updated)? Any service bulletins on this?

Re. the transmission codes that showed up, is it significant that there are no codes for 1st gear? You would think that there would also have been a 1st gear code. Codes that showed up were:

  • PO732 Incorrect gear 2 ratio

  • P0333 Incorrect gear 3 ratio

  • P0766 Shift solenoid D performance or stuck off

  • P0783 3 to 4 shift problem

  • P0789 Shift timing solenoid intermittent

The mechanic is a troubleshooter. I believe he thinks the slam shift is happening as a 3rd to 2nd shift.

ok. the lack of a 1st gear code is not unusual, 1st gear is not controlled electrically, it is always on when the engine is running
the trans uses a sprag to allow it to over run when the other gears apply
the codes are usually caused by a bad connection at the bus but you have eliminated that, and the solenoids all measure OK
the next step is to use a scan tool that can turn the solenoids on one at a time so you can see if they "buzz"
this is called a solenoid audible test
if they ARE turning on then the valve body is mechanically faulty but if they are not then either the pcm or the wiring is at fault.
I have never seen these codes caused by anything other than a bad valve body, a loose bus plate or a broken wire between the pcm and the trans
there aren't any firmware or software updates that will fix this
so a scan tool is definitely needed. one that can "buzz" the solenoids
thats your next step
Customer: replied 4 years ago.

Thanks again. I see I must have transcribed the one code incorrectly. I believe it should read, "P0733 Incorrect gear 3 ratio" instead of P0333

I knew that. I just didn't bother to correct you.
Customer: replied 4 years ago.

Report back on 2001 Saturn S-series with 1.9 litre engine re. electronic automatic transmission fault codes showing up along with intermittent slam shift behavior:

Looks like the sticking valve he shined up was the prime issue. So the issue was indeed in the valve body. Mechanic had a scope on it to graph the solenoids during a test drive and all solenoids including TCC working positively with no fluttering. He said even a human hair would be enough to make the valve stick. It wasn't seized (as in frozen) before he took it apart and cleaned it, but it was very sluggish, he said.

Shifting is beautiful now and very smooth. Has never shifted so good since we got it.

Best part about it is that now we have our own local Saturn expert :-)

Thanks for your input.

Great. Glad to have helped.congrats on the fix
Customer: replied 4 years ago.

Transmission buzz, another mis-shift:

Don't know if the mis-shift and the buzzing are related. Buzzing is faint and most evident when the heater fan is off and can be best heard with the door open and/or the hood open. The type of buzz makes one think of the solenoids but don't know why they would buzz. Buzz is there (continuous) when the shift selector is placed in neutral, and also when placed in 2nd. When shifting into Drive, 3rd, Reverse, and Park there is a brief buzz and then it becomes quiet. Is this buzzing normal? Service manual mentions the PCM pulse width modulates the solenoids for the Torque Converter Clutch (TCC) and Pressure Control (PC) solenoids, but why would I only hear that in neutral and 2nd?

Had a mis-shift "hiccup" again yesterday on the transmission with codes:
P0732 Saturn Gear 2 Incorrect Ratio
P0733 Saturn Gear 3 Incorrect Ratio

Can't say 100% what it was like because my son was driving, but from his description it's like it shifted out of 1st into 3rd, then didn't like the combination and abruptly shifted to 1st, then shifted up again. Fault code light came on, which were the P0732 and P0733 codes. I cleared off the codes and no reoccurrence yesterday evening and this morning. Speculating if there may have been some condensation causing erratic behavior? Temperature was about -6C (21F). Might have something to do with the transmission fluid temperature sensor? Last evening took it for a 12 mile highway run out an then back again. Prior to yesterday's mis-shift I had noticed a couple of fairly abrupt down-shifts on deceleration at about the 60 km/h range (between 35 and 40 mph). Other than that the transmission shifts as smooth as silk, barely noticeable if one isn't accelerating hard.


the buzzing is normal
if it is setting a p0732 and a p0733 with the new valve body then the body is either bad or the input shaft nut is loose
this is common after installing a new vb because the erratic shifting can shock the nut loose
to tighten the nut you need to remove the side cover (which requires a new gasket and a tube of loctite flange sealer (gasket eliminator)
the cover gets torqued to 21 ftlbs and the input nut (closest to front of car) is replaced witha new nut and torqued to 111 ft lbs
you need a chain wrench to keep it from rotating or just use a 1/2" gun and get it tight (this is not the reccomended procedure but it works)
2nd and 3rd gear are both on the input shaft so if they are setting codes I suspect they are out of alignment due to the loose nut
if the new nut doesn't fix it then you have to do the vb again
rebuilt valve bodies are sometimes faulty like that
Customer: replied 4 years ago.

Will convey your suggestions to the mechanic.

Mechanic said input shaft nut was not loose, but not sure how he gauged that. Could be that it needs to be re-torqued, but it seems to me I've seen somewhere that it must be replaced with a new nut.

Valve body was not replaced now, but has been replaced in the past, being a Trans-Tech valve body. Mechanic disassembled the valve body and shined up the sticking valve. Not sure which valve was the sticking valve. The valve was scored a bit, he said. But maybe needs to polish the valve with polishing compound on a buffing wheel and not just clean with fine sandpaper.

I'm speculating if the valve were still sticking a bit and not quite completely returning, that it might buzz against the solenoid if the PCM is pulse width modulating the PC valve?

yes a new nut is the only way to know if it was loose. The old nut is heavily coated with loctite so just checking the torque on the nut is not an accurate way of gaging if it is loose
the loctite will trick your torque wrench
the buzzing is totally normal
but the fact that the vb was not replaced tells me that your issue is internal to the vb (likely...not definitely)
the valves hang up even a tiny bit and they start dropping gears
for a while, saturn started rebuilding the part of the valve body that houses the actual valves (it was called the upper valve body assembly) and we had sooooo many come back with repeat failures that they stopped rebuilding that part of the valve body and started replacing that part with a new section and just rebuilding the rest of the assembly
there are kits available to sleeve the bore and replace the valve for the line pressure regulator
that seems to be somewhat successful as the line pressure valve is usually the reason for the loss of gears and the codes to set
I have never used this kit but it is available on the market as well as rebuilt valve body assemblies that have had that sleeve installed
I only speak of this as a spectator as I have never used one
but people say that it works
maybe your vb had that sleeve installed (called a sonnaxx sleeve kit)
I don't know but I am betting you have either a loose nut or a bad vb again
Customer: replied 4 years ago.

Four questions:

1) Where can I locate an input shaft nut? So far not having success locating a supplier for the nut. Can you recommend a supply source? Can you give me a part # XXXXX the nut? Is it the nut only, or is there a kit with washers/spacers or some such?
2) Can the existing nut be re-used if it is removed and cleaned up? Or do they get damaged in the process of installing/removal?
3) How much play is tolerable? The mechanic said that when he had the side cover off that there was no movement at all in the gear behind the nut. Can shift faults be created if the nut is imperceptibly loose? Or are there other components behind the gear that are affected?
4) Might the input and output speed sensors be suspects in this case?

My thought was to replace the nut and make sure we have that base covered. The mechanic suspects it's not the nut but still some issue in the valves.

the nut is a dealer only part.a Chevy dealer should be able to help you find the correct nut
Sorry but I no longer work at the dealer so I can't provide you with the part#
the input shaft nut is treated with loctite and is actually a fluid seal in itself so a new nut is the recommended repair, if your tech checks it for tightness, it gets tightened to 111 ft lbs
if it is loose, it can cause issues where the gears are not lined up properly inside the trans.
Cleaning the threads and installing new loctite may not provide a good seal so it is not the proper way to fix this
you CAN replace the output shaft nut but it is not a requirement for this repair.
there are no parts except the cover gasket required to replace this nut. No washers or shims etc...
no play is tolerable. Should move like a few thousandths of an inch at the most.
speed sensors will cause codes but rarely a sympXXXXX XXXXXke this
I would think not your issue
Customer: replied 4 years ago.

2001 Saturn SL1 (1.9L) saga:

Thought I'd give you an update on the ongoing saga of the Saturn 2001 SL1 Transmission:

Thought we had it solved with shining up the sticking valve, but not so. Was good for a short time, then began "bumping" on the down shift, I suppose 4th to 3rd, such as when letting of the gas and coming into town off the highway, when it would downshift at about 60km/hr. Then got another slam shift on acceleration from a stop sign.

Mechanic took the valve body apart again but this time when back together and he took it for a test drive he got a slam-shift, but now there was no 4th gear. Well, at least now he experienced it firsthand himself ;-)

Decided to take it in to Trans-Tech for road test/diagnostic. Road test concluded it looked like the transmission itself not the problem. They took the valve body apart twice and still not solved, though did find some gasket issues. Evidently it's the transmission. So had the local mechanic remove the transmission and shipped it in to Trans-Tech for a rebuild. I understand they found the input feed tube was bent or constricted or some such. Of course now all the clutches are rebuilt too and whatever else they do. Should work perfect, right?

Transmission back in the car, but now 3rd gear only. Trans-Tech wants it back to check it again with their breaker box. Only this time will have to get it hauled into the city because too hard on the transmission to take off without 1st gear. Seems strange it's still giving issues because Trans-Tech would have tested it on their dynamometer.

I don't know what fault codes are showing now. Forgot to ask. Will inquire and report back.

Ok. Thanks for the update
Customer: replied 4 years ago.

Stopped back at the garage and inquired about the Saturn SL1 fault codes. They are the same ones that I reported back in April 2012:

PO732 Incorrect gear 2 ratio
P0733 Incorrect gear 3 ratio
P0766 Shift solenoid D performance or stuck off
P0783 3 to 4 shift problem
P0789 Shift timing solenoid intermittent

They will have tested it on the dynamometer before they shipped it out, so it seems highly unlikely that the transmission itself is the issue now, but I suppose it's not hard to leave something amiss on an item that complex. The shop foreman told me he would be rebuilding it himself.

It actually sounds like something electrical to me this time. I understand they did replace one solenoid. Have to have the car hauled in there for them to check it out 'cause it's not driveable now.

Anyhow, thought you would like to know. Will let you know when/if we do finally resolve this. I'm sure it's probably quite valuable on its own merit by now as a unique case study :-)

Maybe the PCM is bad? I never trust rebuilt valve bodies on these but the valve body. Would cause the p0732-733&734 and 789 codes but some of the others I'm not 100% sure on
I'd put a new Chevy dealer valve body, if still sets the codes, go from there

That's my advice
Sorry it stinks
Customer: replied 4 years ago.


Car is back and working fine.

To make a long story short, this last time around with the rebuilt transmission back in and only had third gear, the problem turned out to be the connector (10 wires or so in the connector). Tech I spoke to said someone somewhere had back-probed the connector incorrectly from the rear and in doing so opened up the connectors so they didn't grip the pins correctly. He said it's easy to miss. Apparently the connector has also been updated so it doesn't have the issue of water getting in. He said we shouldn't have any more trouble with that transmission.

Other than that, the feed tube was broken when the transmission came in (I believe that's internal). The first time I took the car in for testing they had taken the valve body apart twice and found issues with gaskets, but exactly what that means is another question. So, good that they found and corrected some issues there, but evidently that wasn't the main issue.

I guess the moral of the story is do the homework and look after the basics before one starts into exotic repairs. Unfortunately not many mechanics are also electrical experts. I felt all along that it seemed like an electrical issue, but you've got to have some place to work to tackle that yourself, especially in winter - and I don't.

Thanks for your help and advice.

well, I'm glad its fixed
have a great day! and summer!
Customer: replied 3 years ago.

Another update on this Saturn SL1 (range switch saga): All still not well despite the rebuilt transmission. P0706 code showed up. Concluded it's the range switch. Installed an aftermarket switch, all seemed fine, then within a day the P0706 code back. Took it back, readjusted switch, all seemed fine and reliable after considerable testing. Next day P0706 code back! Concluded switch faulty; got a replacement, installed it, and within a day P0706 code back (seemed susceptible to cold). Got an OEM (AC Delco?) part, installed it, and so far so good. Looks like we finally have a reliably functional vehicle as of Nov. 22, 2013, nearly 2 years after the trouble started! Makes me wonder if the first range switch on the vehicle was the primary problem all along; it's gone in the trash by now so can't check if it was OEM.