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Hello! I am having a severe problem with the 4T65E transmission in my 2003 Montana Van. I had hooked up in line, an Autotrans 4t65e module that increases line pressure in order to get a firmer shift (is adjustable by a set screw as well). Well, it did not seem to work out well as after a few minutes of driving, although I DID get a firmer shift as expected, the TQ converter clutch was causing a hard kind of "slamming" all over the place and locking up right away in second gear and staying locked up even when braking and letting off the throttle in 4th gear, etc when it should NOT have and staying locked up. So, I removed the interceptor module right away. I used it only for a few minutes. Check engine light came on with a code that stated "TCC stuck on". That's all...After taking it back out and clearing the code and turning off MIL, all seemed to be fine. The transmission then operated and shifted normally once gain for a very few minutes (10 minutes of driving). This transmission normally allows lockup in 2nd-4th gear to keep rpm's low for economy. But it also normally unlocks when braking or letting off the throttle. After a few minutes of driving even AFTER I removed the autotrans module, after being OK for 10 minnutes of driving, it once again then started doing weird things and acting like the module was installed again (which it was NOT), locking up in second gear and staying locked up and even when braking and letting off the throttle. It unlocks ONLY when I come to a stop and it downshifts into 1st gear, or if I press hard on the gas, but it will downshift and locks up after a second or 2 once again in the lower gear. This makes the vehicle very sluggish and hard to drive and is NOT normal. It is acting like the module is still installed, only the shifting is soft once gain without the Interceptor module there. So, I parked the Van and disconnected the battery for a full day in hopes of clearing any retained programming from the PCM, maybe? I also put in a can of BG ATC conditioner. The next day, I took it out and found no change. It is still NOT acting normal. No MIL light is on, but I do not know if the problem is in the Van's PCM, or in the transmission or TQ converter itself? Can someone PLEASE help me here and shed some light on what the heck is wrong with my Van? Do I need to go to a GM dealer and have a TECH 2 scanner put on it to tell which is causing the problkem? No light is on; no codes thrown. But I need to find out what damage I may have caused by trying the autotrans module? Could someone please get back to me ASAP as I am lost here and very upset. The Van has only 48,000 miles on it and UI already just did a tranny servcice w/ a new filter and fluid, etc....just before trying this autotrans Interceptor module in it that is used to increase line pressure (adjustable as well by a set screw) for a firmer shift only. That is ALL it is supposed to do; and I took it out right away after it seems to not work the way it should have.......

Optional Information:
2003 Pontiac Montana Van 3400 V-6

Already Tried:
Disconnect battery for 24 hrs.; Add can of BG ATC conditioner; remove aftermarket module

Customer (name blocked for privacy)

Status: Closed Value: $9

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OK, It makes sens that the T.A.P. have changed...I certainly agree wioth that, however, why did all seem fine for the first 10 minutes after I first removed the Interceptor module and then suddenly, the T.A.P. went and changed to this weird state of constant lockup on their own? That makes no sense to me.......Can you explain why this happened? Right now, the line pressure is normal, I disconnected the battery for a full day to remove any residual programming that may have remained in the PCM's memory, etc and I added a can of BG ATC which is great stuff. Before I put in the module for a try, it was fine....I am lost..any other reasons why?

The "TAP" doesn't reset by disconnecting the battery.As for this programmer you used I know nothing about it or who manufactured it.Yes the BG products are good we use them in our dealership.

Edited by cctmstr on August 12 2007 at 12:59 PM

Hi once more. The company that mfg the module is called "Autotrans" and they were in Canada. They made a LOT of these for all different GM and Ford tranny's. They are now no longer in business. Any idea WHY my Van's PCM kept the changes in T.A.P. even after I removed the module? It should only have worked while it was connected in-line with the large round plug on the tranny....but once I removed it, the adaptive functions should have changed back, like they did for abt 10 minutes...But, if you feel that putting in on a Tech II will correct it, then I will take it to my GM dealership and get it done ASAP. Any other ideas...I am all ears! Thanks! Another quest;

ALSO...I am very impressed with your credentials. So I want to ask you another question which I will gladly pay you for as well. If you tell me how, I will increase the fee when I accept and pay for this....Once I get this problem all cleared up, which I hopefully will, I must tell you that since my motto is "STOCK, NOT!!" AND, I do not like the way the factory has this 4T65E programmed with such a LOW (1700 rpm) stall speed, and it doing lockup in 2 and 3rd gears in addition to 4th gear, etc. So, I want to be able to install a higher stall speed TQ converter as well (2375 rpm...that's all). I did just this on my '96 Lumina APV Van with the older 4T60E tranny and it was GREAT!!! Moved out like a rocketship and no problems at all! I know that I can not do that to this 4T65E tranny without having the PCM re-programmed to allow this. I looked online and found a company called Intense-Racing.com who tells me that if I send them my PCM, or another one that I have put on the Tech II to copy my programming including the security (and do a full case learn as well), I can send it to them and they can add about 6 mph to the TQ CC lockup and release points and that change should allow me to add the 2375 rpm stall converter that I want (stock stall is 1700) for my vehicle. I had tried to do this 2 weeks ago and it would not lockup at all; kept coming in and out of lockup in 4th ("hunting for lockup) since PCM was not programmed for it. Just want to know if, in your opinion, that would work out OK as they tell me it should? Please advise. Thanks! Rich Palais

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