Automatic Northstar owners... (Page 2/3)
Will NOV 12, 08:58 AM

quote
Originally posted by Trinten:

Hey Will,

Thanks. That's really good info to have for when we program the PCM.




What I said applies to the Cadillac PCM. Since you're using the 0411 with different software, you don't need to worry about that.
sourmash NOV 16, 09:43 AM

quote
Originally posted by olejoedad:


The issue with second gear starts is related to lack of signal from wheel speed sensors to the PCM.



Yes, I understood that which is why I went with the question of switch optioned cars. If the factory car has the option to switch off traction control does that switch off the seek for wheel speed sensors and allow 1st gear take off? Maybe not if it is also to control the anti-lock brakes. Anyway, the trans is pretty fricken heavy if you're going to use one. I've got 3. One grenaded by the previous owner when a solenoid let go internally. It's uncommon but I know of two 4t80e transmissions that the solenoid let go and fouled into the rotating torque convertor and broke the cases. My grenaded trans is a DTS/STS unit which has a higher numerical ratio final drive than the ordinary DHS or DeVille one. You can possibly swap in the higher ratio final drive and use a program from the STS/DTS if you wanted to.

If someone is going to utilize a used trans I'd suggest dropping the bottom pan to replace the solenoids with delco pieces, then pull the side pan to replace the TCC solenoid and the actual trans filter. The bottom pan 'filters' are just strainers. I installed a used trans in my DTS and the issue I have is a 2nd gear ratio incorrect message which prevents the trans from automatically switching to 2nd from first. I can manually switch it but it won't do it on it's own. The prob is supposed to be a communication issue between the internal VSS and external one.

[This message has been edited by sourmash (edited 11-16-2019).]

Will NOV 16, 06:06 PM

quote
Originally posted by olejoedad:

The issue with second gear starts is related to lack of signal from wheel speed sensors to the PCM.



Not exactly. 2nd gear starts result when the PCM doesn't get the "desired torque" signal from the EBTCM and responds by going into the torque limited "low traction" mode. Some people have had success by looping the "delivered torque" output from the PCM back to the "desired torque" input.


quote
Originally posted by sourmash:

I installed a used trans in my DTS and the issue I have is a 2nd gear ratio incorrect message which prevents the trans from automatically switching to 2nd from first. I can manually switch it but it won't do it on it's own. The prob is supposed to be a communication issue between the internal VSS and external one.




GMs heavy duty transmissions (4L80E, 4T80E and everything newer), use a "turbine speed sensor", which is really an input shaft speed sensor. The PCM compares input shaft speed to output shaft speed (from the VSS) and determines if the transmission is slipping or not. When it detects a ratio that isn't what it's looking for, it sets a code and avoids that gear. You need to match the trans programming in the PCM to the application the transmission came from and problem that will go away.

[This message has been edited by Will (edited 11-16-2019).]

sourmash NOV 16, 06:33 PM

quote
Originally posted by Will:


GMs heavy duty transmissions (4L80E, 4T80E and everything newer), use a "turbine speed sensor", which is really an input shaft speed sensor. The PCM compares input shaft speed to output shaft speed (from the VSS) and determines if the transmission is slipping or not. When it detects a ratio that isn't what it's looking for, it sets a code and avoids that gear. You need to match the trans programming in the PCM to the application the transmission came from and problem that will go away.



And really you're just saying what I said, Will. Internal speed sensor talks to external and when they don't jibe it sets the code SECOND GEAR RATIO INCORRECT and you don't get an autoshift into 2nd. And AGAIN, the gear is still there if you manually shift. The problem will not go away by changing what is not incorrect already. It's a 9 VIN car with a 9 VIN transmission and 9 VIN PCM.
Will NOV 17, 09:03 AM
A VSS is a particular thing. The input shaft speed sensor is a different particular thing. If you want to engage in technical conversation, terminology matters.

I'm assuming the transmission is not actually slipping...

Did you get your entire powertrain from the same car? Sounds like you didn't. What are the applications of the specific components? It's not that any one is incorrect... it's that you have a mis-match between two.

[This message has been edited by Will (edited 11-17-2019).]

sourmash NOV 17, 10:26 AM

quote
Originally posted by Will:
A VSS is a particular thing. The input shaft speed sensor is a different particular thing. If you want to engage in technical conversation, terminology matters.

I'm assuming the transmission is not actually slipping...

Did you get your entire powertrain from the same car? Sounds like you didn't. What are the applications of the specific components? It's not that any one is incorrect... it's that you have a mis-match between two.



Well, the actual casual conversation between ole and I wasn't an exactly technical one so your statement is devoid of the actual context after the fact. It's nit-picked and can confuse the future reader by the distraction of technicalities. I'm not saying I'm averse to technical discussion, but the statements were a 'what can happen' accounting of my experiences and the actual results you'll see with problems I encountered. I did it right and used a like item VIN 9 in a similar VIN 9 app and it still has problems. If it can be diagnosed and remedied, that's more than the cadillacforums are offering at the moment. All I can find there is use Dex VI and see if it goes away--assuming the hard pieces are correct in the first place.

The trans may be slipping, but not that I can detect. At least not until it downshifts into passing mode and doesn't go into 2nd (revving RPMs but no lower gear engagement). The components could be mismatched but it's an '01 VIN 9 DTS with a VIN 9 trans from a similar year (2001 to 2003) STS installed by a local trans shop I've used for a couple of decades. It's been several yrs since I pulled the trans so I'm not positive anymore what the exact year the STS was, but it was in the range of compatibles as posted on the CadillacForums. I intend to get underneath it today to see if the stamped code tells me that info. For readers, there's an alum tag on the right rear of the trans, and to the left of that is a rectangular boss with dot matrix code stamped which tells the engine code and partial VIN. The engine code tells if it's a VIN 9 or VIN Y trans. I should be able to discern the exact year and model of the car from the partial serial number embossed. I spoke with the owner of the car prior to pulling the trans and he said it worked fine. So, if it turns out to be a Y then how did that happen in between pulling and having it installed will be my question.

If the trans was a Y code, then it should immediately set codes, yes? Because Y codes are something like 3.11 ratios and 9 codes are 3.77ish. The trans shop says it could be many different things but not likely a solenoid problem.
sourmash NOV 17, 11:36 AM
Ok. It's an L37 code so it's a 9 VIN code transmission from that STS. From under the car you can't get a direct clear view even though the pad is the lowest part of the transmission, but an inspection scope works sorta. The cradle is very close to the pad there. The embossed code can be seen but the partial VIN isn't easy to discern. I recorded what is there on the scope but it has a couple of digits that look like characters instead of numbers/letters. Haven't transferred them to the computer to view yet, but the most important part is the L37 code.

The car isn't displaying the 2nd GEAR RATIO message anymore, but when in D it won't shift to 2nd. If at a dead stop I can put it in 2nd manually and take off, it starts in 1st and shifts to 2nd. Then I can manually shift to 3rd. Otherwise it never goes into 2 by itself. Never.

Below are standard camera shots.


[This message has been edited by sourmash (edited 11-17-2019).]

sourmash NOV 18, 07:15 PM
Gee, no technial discussion? Took the car to 4 shops today and got no 2 answers the same. First said clutches, but I said the car works in 2nd very well when manually selected. He said the clutches for the gear might be fine but maybe not the something-something clutches (maybe he said CT clutches or something?). That exceeds my very limited experience. The 2nd place I can't even remember what he said; maybe it was you probably got a bad unit. The 3rd pulled the stick with car not running and said it was low being the problem. I explained it has to be running to even read on the stick, but it was still low when I started the car. Added 1 quart. No changes at all. Took to the 4th and he said look at the electrical connections, or a flattened pin in the connector. Possibly a solenoid.
My orig trans data plate is ML. The STS is VL. Not yet sure if that means anything to the issue. But the DeVille Y VIN eng/trans sets I have are marked VN I think.

My original trans data plate, ML, and the replacement one, VL. Comparable data tag codes appear on Oreilly's site for compatible transmissions, so with reading that I'm reassured that the trans is compatible.

[This message has been edited by sourmash (edited 11-18-2019).]

sourmash NOV 19, 07:27 AM
I've got two Northstar engines with transmissions available. These were pulled by me from insurance totals, each in good condition. Both were owned maintained by long time owners and in clean condition. Each was oil leak free and paperwork indicated long time ownership at time of accident. The problem with Northstars these days is there is almost no adequate help with issues available anymore so you have to be your own source.
Dennis LaGrua NOV 19, 04:08 PM
From what I have seen on You Tube the N* Fieros run mid 13 second 1/4 mile times. That's about what a stock 3800SC would run. The N* has more horsepower but with the 4T80 far more weight.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
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