Bad tranny @ highway speeds

[stsbank]

I recently bought a 95 sts and the motor was swapped to a 98 N* by a previous owner. When i was changing the tranny fluid i found a small piece of clear plastic. It looked like scotch tape some red debris(maybe from a gasket). On the way home before doing the tune up, it drove well on the highway but a few days later it did not want to change into gears while on +40mph. The revs kept climbing so i drove home slowly in fear of doing more damage. I've been told the transmission was on its way out and needs a rebuild/replacement. My question is... can it be an electrical problem, mechanical, or should i just replace the tranny? I will post needed codes later.

[BodybyFisher]

Post codes we can not do anything till we see codes

I do not know how you got a 98 engine into a 95, it should not be possible at all as its OBD2 vs OBD1, ISC vs Idle Air Control to mention a few things

[KHE]

Post codes we can not do anything till we see codes

I do not know how you got a 98 engine into a 95, it should not be possible at all as its OBD2 vs OBD1, ISC vs Idle Air Control to mention a few things

I think '95 was the first year of the plastic intake so the 98 engine should be a direct fit - it would be a huge task if the car were say a '93 or '94. I think the change to IAC came in '95 also but am not sure I know the '96+ were IAC.

[BodybyFisher]

Thanks Kevin, this is the first I have heard an OBD2 engine put into an OBD1 vehicle, plus the possible accessory bolt issues

[Cadillac Jim]

If the 1995 intake manifold and fuel injection were used, the OBD I sensors and control should be OK. I don't know about the accessory mounting. There might need to be some work with a mounting hole or two.

My Jasper invoice gives the part number as the engine for the 1995-1997 model years so I suspect that there is a motor support or accessory mounting issue that would need to be resolved to use a 1998 engine in a 1995. The Jasper requires that you use your old cam covers and intake manifold. Or perhaps the engine is a 1997, not a 1998.

It sounds like the transmission isn't going into 4th gear. The codes will tell the story.

[BodybyFisher]

OK stsbank, sent me this in a PM, so I am posting it here

Hi i am new to this forum. I recently bought a 95 STS and had to replace the spark plug wires, fuel injector wiring, serpentine belt and "plastic tubes connected to the engine" all chewed off by rats that once lived there. The car is finally running but i have codes... po15...po41...i032...a012 and s061 all current. The car runs Great but am having problems with the tranny. $700 to replace but im in college and dont have that kind of money. The STS runs well until i hit the 40mph then the revs drop and run high. Could it be the shift solenoids or something worse?

P015 (E015) ........................................ Open Coolant Temp Sensor Signal

P041 (E041) ................... No Cam Reference Signal from Ignition Control Module

I032 .......................................................... Loss of ABS/TCS Data

A012 ........................................... Low Side Temperature Sensor Circuit

S061 ............................................. Right Front Position Sensor Fault

Lets see what our members think about this. I dont see anything that indicates a tranny problem

[stsevillests]

I also have a 95 STS. When I first got the car the battery was having problems. After replacing new battery a few days later I was driving 1 day and it would not shift out of first gear. I narrowed it down to the positive cable on battery was loose. After buying new battery bolts it worked fine for another week. Then it happened again. I checked the positive battery cable bolt and it was tight, but I could twist the positive cable with my hand even though the bolt was tight. I went to local hardware store and bought a big star washer and put that on the battery side before connecting the positive cable. We have 2 positive cables sandwhiched together with a longer bolt on the positive side than negative side.

Make sure all connections are clean, grounds included, these cadillacs pull a lot of juice, and also make sure the battery is big enough for this car.

Not sure if this will help your problem but its a start before jumping into the transmission.

Also i changed my tranny fluid/scavenger filters and found red/orange rubbery stuff in the pan. Was told that was probably some type of sealer used when doing maintenance in the past. Did you take out the 'hidden' plug inside the pan to get more of the old fluid out when changing? If I remember correctly it took 7.5 quarts to refill mine after dropping the pan and the 'hidden bolt'. I also added a bottle of Lucas transmission fix in mine after googleing for days if I should or not, but the total fill including the Lucas was 7.5 quarts. Yes I measured what came out to know how much to put back in. The Lucas may be snake oil, but I swear it helped a lot, to each his own.

[Cadillac Jim]

In my OEM battery cable for my 1997 Eldorado there are *3* cables sandwiched in the positive battery terminal. These are shown in the FSM schematics for all Seville, Eldorao and Deville models for the 1997 model year. One goes to the starter, one goes to the altenator, and the other crosses over at the bottom rear of the radiator and powers the car through the block of fuses and relays under the plastic cover behind the air cleaner. Corrosion tends to get in there where it is unnoticed and hidden by the red plastic. Pry all three out and clean between them. If necessary add a washer to make sure that they are all tight when the battery cable bot is tight, as stsevillests says. Then reset all the codes and see what comes back.

[stsbank]

Hey guys thanks for your help. I changed the fluid with the correct tranny fluid specified and made sure it was filled. To test drive the car I filled it up with premium. And still got the same results. accelarates till i hit 40 and then the revs shoot up. At a stop light i noticed smoke coming from underneath and went home sad. about the engine I dont know how it was done but it works fine. its hard to figure out what parts to buy. i replaced the serpentine belt and Oh man!!! Had to return several times to get the right belt.

[stsbank]

A few days ago i took the STS to a transmission shop recommended by a friend who has done been there before. They took the transmission apart and said the clutch converter needed to be replaced and the cooler lines were clogged with clutch material. Could this be the cause for the smoke after the test run? Since the tranny is out and disassembled, what should be replaced to prevent any unwanted surprises? Thank you for the much needed advice.

[Cadillac Jim]

I'm not sure what you mean by the "clutch converter." There is a torque converter, a torque converter clutch that I think is hydraulic and doesn't use friction material, and then there are the bands and clutches that shift gears by changing the linked and locked elements on the two planetary gear sets.

If I were to hazard a guess, one or more of the clutches disintegrated and the way to get it out of the system is to flush the transmission cooler and lines, change the torque converter, and disassemble, clean, and reassemble the transmission -- a complete rebuild. This is consistent with what you describe, i.e. that the transmission's 4th gear was basically neutral, meaning that at least one of the clutches or bands was not functioning. Ask your mechanic if this is indeed the case, and then to show you the clutch material in the transmission. If you have a digital camera, it would be great if you could post a photograph here

If indeed you are getting a complete rebuild, the kit for rebuilding the transmission should include everything you need. Be sure that the three solenoids are replaced; one of them sticking is probably what caused the problem in the first place. I'll leave it to better transmission experts than I to list the contents of a rebuild kit for the 4T80E transmission used with the Northstars.

[BodybyFisher]

Wow this scares me, once clutch material circulates you should tear the tranny down and clean it thoroughly.

This tranny should be rebuilt, including seals, steels, clutches, solenoids, sensors, torque converter, etc

[stsbank]

The shop is closed so I'll drop by tomorrow to see the damage. Does anyone know where i could get the needed parts/kit from? I've read on this forum that its best to stick with AC Delco components.

[Cadillac Jim]

Keep in mind that you can get a complete exchange remanufactured transmission for about $1600 exchange from Rock Auto. This includes a warranty.

[BodybyFisher]

There is a standard rebuilding kit that replaces parts that wear out. If you see clutch material, its in the torque converter and it needs to be replaced

Besides the standard rebuilding kit, I would make sure the following parts are replaced

TCC solenoid

ISS Speed Sensor

Pressure Solenoid

Shift Solenoids

The main wiring harness

torque converter

[Cadillac Jim]

I think that there's a torque converter temperature sensor too, but I don't know what model years use them.

[stsbank]

Ok guys. I got the STS back a few days ago and it runs fine. Its such a fun car do drive. But now there are other issues that I'm concerned about. When I shift the car from park to either reverse or into drive it jerks really hard to the point that the entire car moves. I'm planning to taking it back but before would like to get an input from you guys as to what may cause this. Motor/tranny mounts?

[Cadillac Jim]

First, please get the OBD codes and post them here. This sounds like more than one problem, such as missing or bad MAP sensor and missing or loose dog-bones. Second, what is the idle speed? Etc.

[stsbank]

I used the caddy over the weekend and pulled these codes today so I am sure they are up-to-date and they are all current.

P015(coolant temp sensor signal),

P076(transmission pressure solenoid),

P086(undefined gear ratio),

I032(loss of ABS/TCS data),

A012 (low side temp sensor circuit),

S060(Left Front Position Sensor Fault)

p076, p086, and i032 are the ones i am concerned about the most. What does it mean?

[Cadillac Jim]

My OBD I code glossary:

P015 (E015) Open Coolant Temp Sensor Signal

P076 (E076) Transmission Pressure Solenoid

P086 (E086) Undefined Gear Ratio (Transmission Pressure Control)

I032 Loss of ABS/TCS Data

A012 Low Side Temperature Sensor Circuit

S060 Left Front Position Sensor Fault

The codes are preceded by a three-letter acronym that identifies the module that detected the problem, and are followed by an H or HISTORY for history codes and a C or CURRENT for current codes. A Current code is one that is being detected every time the computer checks, and has been seen since the engine was started. A Current I032 means that the EBTCM is off-line, which can happen if a fuse is out, the network data line has a bad connection, or there is an electrical problem with the EBTCM (or DIM, which reads out and displays the codes for you).

I think that P076 and P086 are related. P086 will happen if someone puts a VIN 9 transmission in a VIN Y car or vice-versa, and unless that's something like that is in your car's history, I would look at the P076 first. Someone with a FSM for the 1995 model year may be able to help there. This looks like a sticking servo or solenoid and is likely why the car lurches when you put it in gear.

The S060 means that the left front position sensor isn't working. It's mounted on the frame and has a little arm that his hooked to the lower A-frame, and it measures the LF suspension position. The arm may be off, the connector loose or off (most likely that), or there could be a connector or wiring harness problem elsewhere. This will turn on your warning light.

I strongly suggest that you get a factory shop manual (FSM) if you intend to diagnose or maintain your car yourself. You can get them on eBay and it will pay for itself the first time you fix just about anything.