Transmission shudders at 50mph

[human]

Just got two tubes of Dr. Tranny on eBay for $8.99 w/free shipping. I'll let you know how it works. I'm not a big believer in magic bullet snake oil remedies, but at that price, I don't see where I have much to lose by giving it a try. Still, I have to be realistic. The car is 15 years old and has 109,000 miles on it. I realize no tube of anything is going to fix worn out parts, but the stuff did get rave reviews on a Ford owners' forum (still searching for GM data), so I have reason to hope.

[human]

Yesterday, I took the car in for some minor maintenance--oil change, new air filter, new serpentine belt--and since then, the car has been running rough. The overdrive shudder is still there, but the engine also seems to be misfiring. I had the same problem last fall with my Cadillac and corrected it by replacing ignition coils. So far, I haven't gotten yet a "Check Engine" light.

Are the coils for a 3800 the same as for a Northstar? I've got one left over from that repair and would like to use it here, if possible. I'd do the plugs and wires also, if I could see how to get to the rear bank. Does it require loosening motor mounts and raising the engine as it did with my '91 Cutlass? If so, I'll leave that operation to the experts.

The whole thing is kind of frustrating. The car ran and drove great when I tested it and for the first few days thereafter, but it's been downhill since then. If the car had performed a week ago as it does now, I would have walked away from it, but now I'm stuck with it and have very little means to cover these repairs.

I miss being able to pull up trouble codes on the DIC as I can with my Cadillac. I see inexpensive OBDII scanners all over the place, but I think my '95 model has OBDI. Those seem to be much harder to come by. Will an OBDII scanner work at all with an older OBDI equipped car?

[willwren]

If you lost a coil, it would take out two cylinders. You'd know it. Granted a weak coil can affect 2 cylinders a bit, but the long and short of it is that if you have a misfire, it's most likely plugs and wires.

How old and what brand are you running right now? Misfires under load in OD lockup above 48mph can also very commonly be caused by mild misfire issues.

[Mike Sessei]

When I did my plugs and wires back around April, although they weren't super old, the wires on the front bank put up a bigger fight than on the rear bank, and literally broke apart in my hands at the boot. The rear bank is a little more tricky.
There are many opinions regarding how to get to the rear bank. Two that I found very helpful were these: remove the maxi fuse cover, and (optional) remove the strut tower bar. Lots of folks here have done it successfully without removing the bar, but that's what I did because I thought I'd need the room to be able to get enough leverage to pop the wires off after fighting with them on the front bank. The rears ending up being a dream.
My biggest recommendation before doing the plugs and wires is that you get a spark plug wire puller tool. You should be able to find it at any place that sells car parts for about $5. Also, I found it a little difficult to do without compressed air, but using a bottle brush or equivalent to get in around the spark plug before you pull it to clean the area up should help get dirt and debris off before you pull the plug and blindly try to thread a new (and clean) one in.

[skregal]

When I had my transmission replaced about 8 years ago at 110K miles,
the new transmission did the same shudder going into overdrive. It was
real bad, and did it right off the bat when I picked the car up from the
shop. I took it back and the guy said he knew exactly what was wrong
and they fixed it immediately, and it was fine.
I don't know what they did, however, but it's starting to do it again, 70K miles
later.

[enslow]

A few (I think on this board) have said that disabling the TCC will kill the transmission in the end. If the torque converter is never alowed to lock up, too much heat will build up in the torque converter and kill the transmission.

After doing a basic tune up, drop the tranny pan, change the filter, and refill. Add a bottle of Dr Tranny Instant Shudder Fix as recommended before. While it does not correct the source of the shudder problem (wear in the TCC solenoid bore), it does aleviate the symptoms, and probably reduces further wear.

I did this on my wife's 97 LeSabre (I used GM's shudder fix instead), and it's been fine.

[human]

You're probably right. The misfire isn't that bad and seems to be weather related. The damper it is, the worse it is, and it's nowhere near as bad as the Cadillac was. I have no idea about the plugs. I talked yesterday with the dealer I bought it from and he said he thought the car may still have the original factory plugs, which 109k miles would be well beyond the point of replacing. I'll pull one tomorrow and see.

He says he bought the car from the original owner, drove it himself for a while, then sold it to a friend who bought it for his daughter to drive to college. He said they traded it back on a Honda because the Bonneville was too large to maneuver comfortably on campus. Of course, the real reason they traded it back could well have been the problems I'm experiencing now.

How expensive are plugs and wires for a 3800? I know they're outrageous for a Northstar. You can't touch those platinum-tipped plugs for under $200 a set and wires run about $150.

If you lost a coil, it would take out two cylinders. You'd know it. Granted a weak coil can affect 2 cylinders a bit, but the long and short of it is that if you have a misfire, it's most likely plugs and wires.

How old and what brand are you running right now? Misfires under load in OD lockup above 48mph can also very commonly be caused by mild misfire issues.

[human]

I have no intention of disabling the TCC. It's designed to work the way it does for a reason. I just want to make it work better than it is presently. What you propose is exactly what I have in mind to do. I'm just waiting on my shipment of Dr. Tranny's to arrive.

The transmission fluid is nice and pink, but I have no idea what kind of shape the filter is in. Probably wouldn't hurt to have it serviced, just so I'd know for sure.

A few (I think on this board) have said that disabling the TCC will kill the transmission in the end. If the torque converter is never alowed to lock up, too much heat will build up in the torque converter and kill the transmission.

After doing a basic tune up, drop the tranny pan, change the filter, and refill. Add a bottle of Dr Tranny Instant Shudder Fix as recommended before. While it does not correct the source of the shudder problem (wear in the TCC solenoid bore), it does aleviate the symptoms, and probably reduces further wear.

I did this on my wife's 97 LeSabre (I used GM's shudder fix instead), and it's been fine.

[enslow]

I got my 1999 Lesabre this summer with just 100000km (not miles). It had a bad misfire so I decided to change plugs. As I removed the wires, one of the wires broke right off, and there was a ton of corrosion on several of the plugs. I'm surprised that the engine ran as smoothly as it did.

Plugs and wires weren't all that expensive. I didn't bother getting the iridium ones. The only benefit is a longer lasting plug. Platinum tips were cheap enough, and wires were under $100. And that's Canadian, so yours should be even cheaper.

Just remember to put some dielectric grease in all the boots before installing.

[LeSabre in Buffalo]

Wires are $30 for a lifetime warranty set. Plugs are $12-15 or so for copper plugs. Under $50 with dielectric grease.

Take the strut tower brace off to do the rear bank. It's so much easier dealing with the OEM plugs with it off.

[human]

That sounds financially do-able. Thanks for the info. That's the only part I hated about the Caddy. Anything it needed, you had to add a zero to the price, compared to a regular car.

Is the strut tower brace that bar that runs between the two inner fenders between the engine and the firewall?

Wires are $30 for a lifetime warranty set. Plugs are $12-15 or so for copper plugs. Under $50 with dielectric grease.

Take the strut tower brace off to do the rear bank. It's so much easier dealing with the OEM plugs with it off.

[LeSabre in Buffalo]

Yes. It's the big black bar running across the back of the engine bay.

[enslow]

Yes. It's the big black bar running across the back of the engine bay.

Now why didn't I think of that? Might have saved on bandages. However, I'd still use my leather work gloves when removing those rear wires.

[repinS]

I leave the bar in... but then again I also stand on the motor

[renchjeep]

Just got two tubes of Dr. Tranny on eBay for $8.99 w/free shipping. I'll let you know how it works. I'm not a big believer in magic bullet snake oil remedies, but at that price, I don't see where I have much to lose by giving it a try. Still, I have to be realistic. The car is 15 years old and has 109,000 miles on it. I realize no tube of anything is going to fix worn out parts, but the stuff did get rave reviews on a Ford owners' forum (still searching for GM data), so I have reason to hope.

With only 109k, that tranny should be just fine, unless neglected or abused. You say the fluid is nice and pink, so I would say it must be in decent shape internally. My trans went out at 187k. I bought the car (actually got it for free!) at 160k, original trans, and it was not really well cared for. Plus, my right foot is quite heavy!

I think the "Dr. Tranny" fix will work fine for you.

Please do keep us posted.

[human]

My tube of Dr. Tranny came today, so I poured it into the transmission and took the car out for a little 15-mile jaunt. While it definitely shifts more smoothly, it still shudders going into overdrive, just not quite as bad as it did before. I'm going to take a little bit bigger jaunt later this evening down to my parents' house about 100 miles away. I'm hoping that trip will give Dr. Tranny a little more of an opportunity to do its thing and further smooth that shudder, but for now, I'm not terribly impressed. As I said earlier, I'm enough of a realist to understand that no bottle of anything is going to cure worn parts.

On another note, I was out running errands earlier and the car started idling very rough at stoplights and eventually started missing a bit at slow speeds as well. It felt like the Caddy did when the coils were going bad, so I stopped at NAPA and got some plugs and wires. They had standard AC plugs for $1.70 each, so I got six of those. Curiously, when I got back into the car and started it up again, it ran just fine. It'll probably be early next week before I get those put in, but I'll let you know how it goes.

[enslow]

Did you change your tranny fluid also? Even though the fluid looked good on the dipstick, there was a lot of black powder in the pan. No metal flecks, just powder. Changing the fluid definitely helped cure the shudder. In fact, on my old '92 which used to shudder really badly, it wasn't until I had a tranny flush to clean the torque converter did I get rid of the shudder.

If you haven't changed your fluid, I'd change it now, then once again 6 months later or so.

[blazerk5drew]

This Is most likely a problem with the torque converter and/or valve body. No Additive or "placebo" will fix anything IMO. If a transmission is acting up that means that some component is malfunctioning and needs to be fixed. I had a similar problem with my olds 88 (same transmission). The issue is a worn TCC apply valve caused by improper factory tolerances. The update needs to be done by somone who is familiar with taking apart a transmissions valve body and making modifications. If the tq converter shutters too much, the friction materials may be worn. I would replace the converter and have the updates done. It may be time to investigate a rebuild as the problem is only going to get worse. Also make sure that the transmission cooler and lines are not plugged. I had the trans rebuilt in my car with a shift kit and a 3000 rpm stall converter along with the valve body updates. It ran me about 900 and I pulled the trans out myself. The stall converter will wake this car the H*LL up! fyi

Also, listen to the other advice in here and make sure all of your preventive maint. is done. You will be amazed how much they can restore a car.




Refer to the topic below for some help with TC problems



viewtopic.php?f=19&t=14338&start=0&hilit=1870

[enslow]

While an additive or fluid change may not cure the source of his problem, it can reduce it significantly as it did in my wife's Lesabre. Certainly there's no harm in trying. I'd agree that if, after a fluid change + additive, there is no improvement in the shudder, he'd best have the source of the problem fixed.

[Bugsi]

I didn't remove the strut tower bar to replace my plugs, I just reached back there blindly and did them. Somewhere there is a classic photo of Bill standing on his engine to get to the back plugs. (Anyone? Anyone?)

You said you got AC plugs for $1.97 each. That seems amazingly inexpensive to me, I'm wondering if the plugs you bought are going to be okay for your engine or not. Anyone else worried about this? There are many many plug threads on this forum. If you search, you'll find recommendations on which plugs to use and not use.

(I just wanted to raise a red flag on this before you install them; just get some confirmation here that the plugs you're going to put in are okay.)