patrick sieben

Have just installed my 700r4 from pro-built. It was referred to me as a good solution to my tranny whoes. I once posted on a vette forum why won't my car go fast. It was because the old tranny wouldn't lock-up and stay locked at high speed. However that is not the issue now. My former trannny wouldn't lockup warm and neither does this one so it seems. It slips an therefore is running 200°F. Dana at Pro likes the tranny to stay well under 165°F. Now I still need to find his special fluid locally or get an tranny cooler. I run dextron III. I wonder why the tranny will not lock. Of course I checked all the electrics and they work fine. Light goes on and off on the aldl connector. If grounding the f pin to the a pin it will not apply either. although the coolant is above the specified temperature and I'm driving above and beyond 40 mph. Funny thing is the car, when cold does it too well it will be bogged down completely (no matter to me). I almost seems it doesn't shift into forth either because it runns 2200 rpm at 60 mph and when cold it will be running say 1400 rpm. It sucks because of gas milage and am afraid of doing long distances witouth overheating 700r4. SO what is the deal? Solenoid fried? When hot will let current through but does not apply! Torque converter is a brand new vigilante 2600 rpm stal. Of course I can start taking everything apart but I want a cause. ANy suggestions?

Pro Built Automatics

Call me?

patrick sieben

Of course I will call. In this manner I was hoping to get a quicker answer. It was sunday and I tried calling you. The time difference is 9 hours so I will try again tonight.

I guess it is a sticking solenoid and that the pan has to be dropped to replace it.

But I would like to get some more input from everyone.

patrick sieben

I would appreciate someone who has knowledge. Pro-built is sending me a switch?? and some special fluid thinking the temperature is the cause of it all. although I did measure temperature up to 220 F directly in the filler tube and 185 on the surface of the pan I truely don't think it should effect the working of the TCC lockup. I was going through the GM manual I found there 16 types of transimssions all with their own way of applying the TCC. I have a canadian car. I wonder what system Pro-built put into my tranny when I ordered it. Of course I ordered it by stipulating it was a 1988 corvette. But suprisingly in the manual there are differnt configurations. Now what I think is that I have a solenoid with a temperature switch!!!! I wonder what Ed Wright did on my ecm chip. If these two don't talk to each other correctly it would explain it right? I noticed on diacom that the tcc was ON on the highway, but it wasn't in fact. It seems with the canadian tranny that when all is cold the TCC will apply without the ecm comanding it if in third or fourth gear. That would explain why tcc locks up with me cold and very consily refuses to do so when hot. My former tranny didn't do this. I wonder.

patrick sieben

Correction I have a Type 9 transmission YDM 1988. My car originally did NOT have e temperature sensor in it. WHich makes me wonder even more when I think of all the different terminal combinations my ecm is expecting.

91L98Z28

patrick,

with regards to your TCC solenoid, here's some info that will hopefully help.

just drop the pan on your old trans, and swap the entire harness and switches into your new tranny. Here's what I'd do.

(1) drop both pans (new tranny and old tranny)
(2) put old wiring harness in new tranny. If your old trans didn't use a temp sensor, you won't have a connector for the temp sensor, so leave it unplugged. it won't hurt anything. (if your old trans did have a temp sensor, then put your old temp sensor in the new trans).
(3) put your old 4th gear switch into the new tranny. it may be different (there is two types), so it's best to use the one that goes with your car/computer. Test it before you install it (use 20-30psi of compressed air).
(4) test the TCC solenoid, just apply 12 volts to it. if it doesn't activate, replace it. they are often defective.

Your goal is to make the new trans electrically the same as the old one, so that your car and computer know now to control it.

If you don't have a trans cooler, INSTALL ONE!!!! if your trans is truely above 200F that is bad.

Make sure you have the trans filled correctly, 700r4's are pretty sensitive to fill level.

When everything is working correctly, you should observe the following behavior:

(1) TCC locks up under light throttle as you pass about 40mph.
(2) As you are driving at high speed (50+mph) and in overdrive, manually downshift to 3rd while holding steady light throttle. The TCC should unlock for two seconds, then re-lock. The computer does this to prevent shocking the drivetrain.
(3) TCC unlocks immediately when you tap the brakes, and relocks immediately when you let off the brakes (assuming you are above 40mph and at light throttle)

Good luck. Once you get that pro-built working right you'll love it. Dana knows what he is doing so talk to him on the phone and he will get it sorted out.

patrick sieben

Thanks for the answer!!! I am learning everyday! I have found out much more. WHen you order a trans you better know what wiring system you have. Turns out my old trans was a rebuild one as well. so I have nothing to go from besides the code on my prom on the ecm, I guess and the fact that my chasis number says I have a YDM type 8 transmission. In looking that up in my GM manual it shows a diagram that does not include a temp sensor. The temp is done by the ecm. It will allow tcc to engage above 65 degree C and 4th apply and 40 mph. Now I asked DANA wat he had done and he wasn.t really sure. He blabbed real fast about the most common transmission and it usually doesn't give a problem exept for me. It is too bad he didn't want to take the time to explain his schematics. I could compare it to the YDM code to see whether it was the explanation to my TCC blues. However I really appreciate the thought of using the old trans for components I haddened thought of it for some stupid reason! The final question now remains. can someone explain if it could be possible to have a TCC disengage when the internal temp switch applies while ECM commands tcc apply??? I don't know what scheme Dana has used to my disappointment there are two schematics in the manual that shows a temp switch all other 14 don't

patrick sieben

Called Ed Wright who made my chip, all he could say is he made a chip compatible to the code of the "original" chip. I hope it was. That still doesn't explain what the ecm is really doing and neither did it explain wether or not fastchip knew. The fact remains that the wiring to the trans can be different for many 88 models and therfore I'm sure the ecm program too.

91L98Z28

yes, the wiring and ECM programming is different across different models. some have the temperatuer switch, some don't. some have a normally open 4th gear switch, some have a normally closed 4th gear switch, and i bet some don't even have a 4th gear switch (but not sure on that one).

That's why (in my mind) it is important to re-use your original harness that matches your car and computer. I seriously doubt Ed would have modified the way your computer works iwth your transmission, most of his stuff is timing or fuel changes (calibration changes), not functional changes the way thigns work.

The ECM programs are differet on different models, but not on the same model. anotherwords, all camaros equipped identically to yours will have the same chip and the same trans wiring. some of the trans wiring is interchangable, some isn't.

just put your original wiring back in the new trans. then the trans will be electricailly the same as your old one.

Pro Built Automatics

The most common wiring I use is the one where the temp switch is used and the 4th gear switch is normally open. Could the temp switch be causing this problem? maybe.... I would eliminate the temp switch when you get the pro-fluid and the new 4th gear switch. Since it changes when hot, this might solve it. At what temperature does the lockup not work? And at what temperature does the lockup come back? If it is consistent, (when lockup & not wanting to lockup occurs) then the temp switch is most likely the culprit with the existing wiring setup. You mentioned that the first (rebuilt) transmission had a similar problem. As stated earlier, I think that eliminating the temp switch should solve this problem. If transfixleo has any ideas on this problem, I would welcome them.

91L98Z28

patrick,

you should go with dana's advice on this one, he's got a lot more experience with this stuff than me and he knows how it's supposed to work.

When I had to troubleshoot lockup probs in my tranny, I was a bit of a special case because my camaro (a 1991 5.7) uses a tranny which has no temp switch, and a normally closed 4th gear switch, whereas most trannys apparently use a normally open 4th gear switch. So the wiring that my car expects is fairly unique (actually - any 90-92 5.7 car, as they all use the same PROM. maybe other F-bodies use the same switch too, but i have no idea.). If you have a factory service manual it will tell you what you're supposed to have.

If you want to understand what the car is trying to do with the lockup, get a service manual for your car...they have complete schematics and document what type of switches are supposed to be in the tranny. The factory schematics will greatly help you understand what's going on, they did for me (along with dana's help). it can be frustrating but stick it out, it's well worth it!! i've got about 1000 miles on my pro built now and love it.

good luck!

patrick sieben

Dana, glad to see you are back on the computer. The temperature seems to go up and stay up. Until I get your special fluid, maybe even get a cooler although transmission life will shorten at 220-230 it should cause performance problems right? Check the wiring (which can be measured from the outside how it works right?) Maybe I won't ever see the temperature go up an under. Therfore diagnosing it as you suggested will be troublesom or impossible. I'm glad that you are telling me it COULD be the wiring, according to your explanation that would probably be a type 15 transmission with codes FAM, FMM, MAM,MDM, MFM, MKM, MLM, MMM, MPM, MRM, MUM, MWM, MXM, MZM, THM, TJM, TKM TLM TUM, TXM. If we have that confirmed I will be able to do an electrical analisys and know why I'm taking everything apart. I'm the type of guy that likes to think 15 minutes before I do something to get the job done in 30. Some go a do it and find out it took 90 without realizing anything. I want to avoid that situation so please bear with me.

patrick sieben

Sorry: Type 15 transmission is with the A terminal going through a pulse switch wich is normally closed, then into the solenoid which has a diode surge protection to D which is the ECM ground. Connected to D is a normally open temperature switch going to the ecm and connected to the 4th gear normally open switch to ground. Is that what you sent me Dana?

patrick sieben

Forgot to ask the most important thing. Do I get to reuse your pan gasket when dropping the pan?

Rustynutz

patrick sieben

If taht last comment was unclear it was a suggestion to those wanting to purchase a transmission, to be sure of what they get. There are over 15 different configursaations in internal wiring for the tcc lockup. Tranny rebuilders seem to use a common configuration as apposed to what you NEED. If it turns out it doesn't work you will have to drop the pan and rewire it yourself. I hope that will resolve the problem for me. But then again maybe I'm all alone in corvette land and the only one with a problem like this. I just figured to keep this thread going. I would also be interested to know if camaro has so many versions of the tranny. I wonder why GM put so many of them into the market. I wonder why GM has so many versions in one year?

patrick sieben

Dana:

Of course I haven´t tried running the car with a thermometer hooked up to see at what point it stops locking ttc up. However looking at my coolwater temperature and thinking the two would run close to each other I would say 185 F. Especially because I'm mild driver to a cold car. At what temperature does the switch activate?

Pro Built Automatics

I am not sure of the exact temperature, but 185 F sounds close to activating the switch. I see three different types of wiring setups on most of what I build 1988-1992 700R4's. I use the most common, the 4th gear switch normally open, along with the temperature switch. I think I have had 2 or 3 complaints about this in the last few years. I did not think of sending you a pan gasket along with the fluid & switch. I will see what I can do?

patrick sieben

We are defintely getting there. Thank you dana. Now only I will do the work get a gasket from GM and see if all is resolved. Thanks