Transmission Shudders... Easy Fix?

The car only has 68k on it and doesnt have a misfire but i do plan on doing plugs/wires/fuel filter to pretty soon just because i dont know how long theyve been on the car.

Now that i think back to when i got my regal it had a similar problem that was solved with a filter change/lucas oil so ill try that to. BTW im a skeptic of most of these "miracle in a bottle" formulas but Lucas is the real deal as is solved alot of transmission problems in my past cars and when i was working at advance all the people i recommended it to had nothing but good things to say about it.

I notice that if i let off the gas a little when its about ot shift that it doesnt shudder so im hoping its nothing TOO big. The car is in GREAT shape and drives like new so worse comes to worse i would end up dropping it and having it semi-rebuilt.

What does the trans fluid look like now? 1997 Riv with that many miles is great but if the previous owner didn't do much with the fluid in that time, it might be kinda ugly looking. Definitely pan drop and filter change while using Dex VI as replacement and go from there. Bad wire could make the same symptoms as wells as a bad plug.

Hope it's something simple.

Im hoping for the getting my school finacial aid check ($1200) within the next 2 weeks and the plan is:

-Trans flush with dex VI/Lucas
-Plugs/Wires/Fuel Filter
-3" DP or possibly SSAC Headers
-3.5 pulley (with headers, intake, a REALLY good tune and factory duals I think i shouldnt be getting any kr)
-Aeroforce Interceptor in the driver door air vent. (tons of gauges, plus a DIC make it worth it.)
-20% Tint
-Black out headlights, tint the rest.
-Get it debagded, buffed out and waxed professionally.
-Dual dual exhaust tips
-Pioneer D3, 2000rms system
-Call it a day and drive it till the wheels fall off

Rick i dont know if i asked you yet but what do you got planned for your riviera again?

Forget the Lucas...

I would change the order to:

-Plugs/Wires/Fuel Filter
-Trans flush w/ DEX VI

That way, you'll know it wasn't the transmission if the wires fix it, and you can forget the Lucas. Otherwise, you could end up like this guy from Hotrodders.com:

"bought Lucas Oil "Transmission Fix" as it advertised it would free sticky valves and I figured it was a reputable, quality product.

I poured it in slowly with the trans fully warmed up and engine running. Was surprised how thick it was. I let it run awhile to help mix it in, then tried it.

Was dismayed to find it would hardly go in gear and, when it did, acted like it was slipping big time! Tried going from reverse to drive & back several times in an effort to work it thru the valve body and mix it in better, but no luck."

Hello Guys,

I have yet another question. By the way, thanks for the help on my previous questions. I beleive this problem to be common, but I am looking for some advice (I apologize for not having the mph stats). Just a disclamer, I haven't had too much expereince with transmissions.

Issue:
Normaly as I drive down the road at 75 kms the trans shifts, when I hit close to 80 kms the trans shifts into OD. As I drive at a clip of 80 to 87 kms, on slight inclines the car will shrudder. I keep the car speed very steady and drive for higher gas milage. From my understanding it is a TCC lockup issue. I have read about tapping brakes and changing driving style. Most of my driving is on country roads, however, I drive in town for 10 minutes before I hit the country road for my commute.

I have just moved out of the country, so I get in my car and drive 85 to 90 km per hour down a road with no stops for miles and miles. It is presently cold, as we have snow. What I have just noticed is that the car does not shift into its final OD until I get a mile and a half down the road. it just keeps the RPM up to 2000-2200 rpm until I hit that 1 1/2 mile mark and the goes into OD and down to 1500 rpm.

Questions:
Is this normal, or do I have a problem?
Is there any longterm consequences of the late OD lockup in cold weather?
Is there a component I can change out to help with the TCC lockup shrudder? (I have searched through sites, but I have been unable to find a straightforward answer)

I do not know when the last time the filter/fluid has been changed. The fluid is still red, but is a little darker then fresh fluid. I will change out fluid/filter, but will not do a trans flush. Since I will be taking off the pan, I am looking for advice in case there is a part I need to change when I am in there. I would hate to have to pull off the trans pan twice.


Some history on my car:
The car is a 1996 Supercharged Riv, all orginal with no mods. It has 215,000 kms on orginal trans/engine. I have owned the car for the last four months and have driven 7,000 kms in it. I have been chasing problems/fixing things on the car since I bought it. It sat for a year before I bought it. I have replaced the following: plugs and wires (AC delco), air and fuel filter, intake manifold gasket, valve cover gaskets, Throttle body gasket, Supercharger coupler. Changed out injectors due to plug injector. Cleaned TB, cleaned IAC, cleaned MAF, traced/checked wiring, cleaned all grounds, replaced worn out vaccum lines.

Thanks for any help,

Rod

Well, it could be a few things. A fluid/filter change may help, but that "shudder" is usually caused by a clogged/failing TCC solenoid (PWM solenoid) inside the transmission. This causes the TCC to engage/disengage when it's not supposed to, especially right around 44-47mph. Quite a few of us have had the pleasure of having this solenoid replaced. A trans flush may help also. I've seen the screens on this solenoid get clogged with debris. This part CANNOT be changed simply by removing the pan. This LINK provides more info.

Why will you not do a trans flush? I'll assume it's because you've heard of catastrophes because of trans flushes....it's old school thinking. When done properly, and with the right machine, it won't hurt a thing. Simply doing a filter change DOES NOT remove all of the old fluid......

When cold, it's normal to see a delay on the TCC lock-up (at least my '98 has always done it). I believe the TCC is enabled once the trans is warm. Disabling the TCC when cold helps to more quickly warm up the trans, imo.

The shudder you describe is a very common complaint with 3800 transmissions. My solution was to re-tune the PCM to more easily release the TCC under load, as I prefer it for performance reasons anyway. The software costs about $300 to custom tune all of your drivetrain parameters, or you may have it done by someone with a tuner.

AA wrote:

When cold, it's normal to see a delay on the TCC lock-up (at least my '98 has always done it). I believe the TCC is enabled once the trans is warm. Disabling the TCC when cold helps to more quickly warm up the trans, imo.

The shudder you describe is a very common complaint with 3800 transmissions. My solution was to re-tune the PCM to more easily release the TCC under load, as I prefer it for performance reasons anyway. The software costs about $300 to custom tune all of your drivetrain parameters, or you may have it done by someone with a tuner.

Maybe, but a properly functioning transmission without tuning doesn't shudder. If you have to tune out a shudder, you have a malfunction.....

You can tune your "shudder" any way you want, but a failing solenoid is gonna come back and bite you "you know where". I'm sure this shudder he's describing isn't something to "tune out"....

No, you're right. Maybe it's not the best solution to get back that soft, smooth, low-RPM thrust that many Buick customers are looking for. However, I got 150k+ miles out of my first transmission, a good portion of that time with the TCC tuned to "relax" with a lower throttle threshold. The result is better throttle response, and if you have the vibration problem at low RPM, it goes away because the torque converter clutch is under a lot less load. My new transmission did not have the shudder, but I used the same tune anyway. 65k+ miles so far on the new unit.

does your car shudder at other speeds ? What you call "final OD" is your TCC locking up in 4th gear (OD).

It is normal for it not to engage TCC lockup when cold.
You describe climbing hills at 80km/h which is the lower end of the TCC lockup speed range. Your engine is seeing a substantial load, but you're intentionally keeping it a hair above the speed at which the pcm would command TCC unlock. The riv has, IMO, a very high TPS position trigger for its trans settings. That's why you can go to almost 50% throttle in the hill and keep it in 4th with the TCC locked up, which isn't necessarily a good thing. Some people can associate the high engine load/ low speed/ tcc lockup with a shudder. When Aaron modified his tune, he changed the %TPS at which the PCM commands TCC unlock/downshifts, and possibly mph triggers too.

IDEALLY, you should check the PCM with a datalogger or good scanner (tech2, Powrtuner, etc) to see if it is commanding the unlock and relock. If is is, check:
1. Intermittent false-on signals from brake switch and/or cruise control release switch.
2. TPS for spikey output (this is a guess)
3. Programming may have TCC lock/unlock setup with improper hysteresis at the speed you're driving. Generally only happens with custom tunes.

If it's not the PCM, check:
1. TCC enable solenoid may be sketchy. Follow Abbadon`s link to change.
2. Converter clutch material may be just about worn away. This requires torque converter replacement.

Like Abbadon mentionned, the EPC solenoid tends to get clogged up with debris. This is because it has the finest the transmission and will catch things that pass the pan filter. Maybe someone here can post a scan of the shop manual page that shows the location of the filter so you can clean it out. Then basically hope it`s only clogged and not torn from a massive accumulation of debris. The shop manual SHOULD also have a diagnosis procedure to allow you to Ohm the solenoid. Maybe some gentle soul can scan that for you too...

Finally, if you are feeling up to it, you could also install the Transgo 4T60E shift kit which will address your issue. Seeing as how this would require you to take stuff apart you could check your solenoid and filter at that time.

Guys,

Thanks for the quick responses. Abbadon, you are correct with my thoughts about trans flush. I have heard many horror stories about improper trans flush. I don't have a shop/mechanic that I know as I have always done my own work. It’s getting harder since this car is more complicated than previous cars. I was hoping a trans fluid/filter change would suffice. Thanks for the link on your TCC change.

Jason, the car only shudders when I am above 75 kms. I can pretty much recreate/feel the proper scenario to create the shudder. It really only does it as I get up to speed through though the 75 to 80 kms per hour range. The TPS voltage is good and I do not think it is the brake switch as it only happens as I get up to speed (but to be truthful, I never thought/knew about this). I have recently replaced the intake manifold as it was giving me some driving issues such as surging and slightly erratic idle. The LM gasket seems to have solved some problems. But this surge at the specific speed when I am driving for "mileage" is still there. I also noticed the car shuddered yesterday at a little higher speed (85 kms).

Some more Questions:

1. Is the screen that sometimes clogs, is it on the actual TCC solenoid?
2. When I open up the side of the case and separate it from the rest of the trans, do I have to install a new gasket?
3. I have looked, but cannot find ohm resistance figures for the TCC solenoid, if anyone knows these I would appreciate the information?
4. Just double checking, as noted in Abbadon’s link, since I have a 96 Riv is it possible for me to change TCC solenoid and check TCC filter screen without dropping the engine cradle?

Thanks for the help guys; I would be lost without the site. I will probably rip into the TCC solenoid in the coming days.

Rod

Rod, you stated:
"when I hit close to 80 kms the trans shifts into OD. As I drive at a clip of 80 to 87 kms, on slight inclines the car will shrudder. I keep the car speed very steady and drive for higher gas mileage

Is it possible that what you're feeling is 'surging' and not 'shuddering'?

It sounds to me like you're describing something that my car has always done, except that it's the engine, not the tranny.

My car will shift into OD and lock up the TCC at 42MPH. At any speed from there up to 50+MPH, if I take a moderate hill and "drive for economy", my engine will surge from the 'lugging' of the engine and the spurts of knock that make the PCM yank out a bunch of timing, then restore it, then yank it again. Something that someone else might describe as shudder...

If I lean into it harder and provide Power Enrichment, or tap the brake or release & reapply the throttle to disengage the clutch, the problem disappears. Before I opened up my intake & exhaust plumbing, it would even do it at higher speeds on one certain hill on the freeway.

I have Californicated 91-octane swill, so I wasn't surprised - this symptom will also disappear when I mix up a tank of 93.

Does this sound like it might be what you're experiencing? Also, what octane are you running?

Hey Rod, mine does the same thing your describing, it hangs at around 80km then struggles there until I give it more gas. I had dealers and independent shops look at it and they said it required a pricey overhaul. But I am pretty sure that its the TCC solenoid that needs to be replaced. I have the same year Riv, and I would be interested to know if it is possible to remove the side cover on our car. If you do try it, let us know or even better, maybe you can post some pics.

sigh...the post got moved between typing the reply and hitting send so it disappeared. So here is a brief summary.

Read what Eldo said. That's what I was getting at in my previous post.

I only have a 98 G-body svc manual, so I don't want to give you inaccurate info wrt your questions. I used to have the 96 gm trans rebuild manual at home. I can look for it if no one chimes in with the correct info from the 96 g-body manual. If you replace the solenoids, be sure to stick with GM replacements as transgo has pointed to a rash of problems with replacement solenoids.

I don't believe the screen is built into the solenoid itself, but I will look it up in the manual. Here is a link to a friend's write-up of the installation of a transgo shift kit on a 4L60E. It isn't the transverse mount 4T60, so the point is only to give you an idea of what you are looking for. Scroll down to 3a.

Jason wrote:

sigh...the post got moved between typing the reply and hitting send so it disappeared.

Yep, I had the same thing happen when I was previewing my own post... Had to rewrite a shorter version before I forgot what I was saying.

Good thinkin Eldo and Jason. You are both dead on about the "surging" during lock-up and pulling timing and what-not. Every 3800 car I've driven does that to some extent. As far as removing the side cover on a '96. Yes, the trans needs to be lowered like the Write-up. As far as I know, and from what Steve posted, the Series I is the only one that can get away with simply moving the cover aside. All Series II setups are the same.
As for the screen on the PWM solenoid, it is literally located in the nose of the solenoid. I don't think an Ohm check of the solenoid itself will help find anything......this issue comes about with no SES light, nor any "failures" you may find electrically. You could follow the flow chart top to bottom and everything would check out ok (like mine did). Only difference is, I had intermittent launch shudders, delayed 2-3 shift, and in-and-out of lockup at 44-50mph. It was annoying as hell. All of these symptoms were totally intermittent, except for the lockup problem at cruising speed.

Jason and Eldo,

I thought about that and it may be the situation. But when I experience the surge/shudder I just don’t expect a car to drive like this, it is very pronounced. My wife even notices it.

These are my thoughts; please correct me if I am wrong. If the engine is surging, I would expect to see the RPM fluctuate. However, the rpm stays consistent as the vehicle surges/shudders. Granted the surging/shudder only lasts a few seconds. I have experienced surging before and it seems to be different. But I have been chasing down problems with this riv since day one and all the time behind the wheel dealing with issues is starting to melt together in my mind. So to be honest I cannot confidently say surge or shudder, but I am leaning hard towards shudder as it feels different than the surge I sometimes got with the LIM leak.

Jason thanks for the link. I will try to attempt the fix in the next few days while I am on vacation.

Forgot to mention, I am running 91 octane from Shell.

Thanks,
Rod

IF you are going to be going through the trouble of lowering the trans, I would install the transgo shift kit. It will address the issue permanently. PWM has been responsible for a lot of the issues you mention on 95+ GM cars.

If you're out my way, I can also help you load an upgraded tune into your car.

Rodman wrote:

Jason and Eldo,

I thought about that and it may be the situation. But when I experience the surge/shudder I just don’t expect a car to drive like this, it is very pronounced. My wife even notices it.

These are my thoughts; please correct me if I am wrong. If the engine is surging, I would expect to see the RPM fluctuate. However, the rpm stays consistent as the vehicle surges/shudders. Granted the surging/shudder only lasts a few seconds.

Thanks,
Rod

Of course I can't say for certain without being there, but I would say that everything you just said are things that I would say about my surge... It really should not be doing it, it IS noticeable to the point that passengers would pick up on it, it only lasts as long as I stay in that narrow zone of load & lug, and the tach doesn't move much because the clutch is locked up, and thus the wheels will drive the engine during that time. I should think that if the TCC was shuddering/chuggling/etc during steady driving, that is when the tach would move, and the motor would race a little bit...

I would also think that a TCC problem would only get worse with speed and rising wind resistance... I suppose the real test is what it sounds like - When the lug/ping/retard sequence hits, the engine & exhaust sound rather like you're starting to suck air from the fuel tank.

As was said, if your car is on an incline going about 41 to even 50mph and the TC is locked, you'll get some surging on a worn trans. If it's stuttering/bucking really bad, I assume worn or malfunctioning TCC solonoid. These cars (esp the L67 powered ones) have a pretty crazy FDR which causes a lot of load on the motor when the TC initially locks in 4th gear. If you're on a decent incline, it will cause this surging. I've noticed this in 5 3800 powered cars to date. My solution? I let off the gas for a tic and then get back on the pedal far enough where the TC will not lock up until I've finished the incline or whatnot.

A fluid change couldn't hurt as well for the time being unless it's bad enough where you think parts need to be changed.

HTH

I am almost positive GM called this "hunting" not "surging" and they had a TSB on this that had a Tech II flash for the PCM. Or was it that you were supposed to have the PCM "un-learn" the lockup point by disconnecting the battery for a couple hours? I can not check that though, maybe someone else will.

Albertj

Quote :

I let off the gas for a tic and then get back on the pedal far enough where the TC will not lock up until I've finished the incline or whatnot.

This is exactly what adjusting the PCM program does, except it happens automatically - you don't have to physically let your foot off the gas.

AA wrote:

Quote :

I let off the gas for a tic and then get back on the pedal far enough where the TC will not lock up until I've finished the incline or whatnot.

This is exactly what adjusting the PCM program does, except it happens automatically - you don't have to physically let your foot off the gas.

I still think Rick is describing the same KR symptom that Jason, Scott and I were, not a worn tranny...

BTW, mine did it from the time I bought the car at 69,000 miles.
BTW, again: What does FDR stand for?

albertj wrote:

I am almost positive GM called this "hunting" not "surging" and they had a TSB on this that had a Tech II flash for the PCM. Or was it that you were supposed to have the PCM "un-learn" the lockup point by disconnecting the battery for a couple hours? I can not check that though, maybe someone else will.

Albertj

Actually, there are no Bulletins regarding this issue for a '96 Rivi. The only Bulletin I could find related to this issue was this....'97-'99. And yes, there is an option for "hunting" when searching for a trans TSB...