Thread: trans help!

Well, I've had some issues with my trans. for a while now with erratic line pressure and converter flutter/slow lockup. Non of these conditions exist though when trans is cold but start to show when the trans get hotter.

I'm running a external cooler, trans go shift kit on 2, and the pcm line pressure is jacked way up. I have the DHP tuner so I have no converter duty cycle access. Trans. only has 28,000 on it and the converter is brand new from GM. Just today, I installed the TAC adaptor to see if this would help and it did for the most part but I'm still seeing some issues when it gets hot. Still get a little converter flutter(very small now). Funny part is the original trans exhibited some of the same issues, only difference is the cluches were toast by the time i got the car. Anyone have an ideas??

Have you tried to do an entire rewrite on the pcm? Sometimes that helps with the TCC issue. You mention the trans has 28K on it, is this original miles or was it rebuilt? What parts replaced if rebuilt? Was the pressure control solenoid replaced?

Originally Posted by Trannyman95

Have you tried to do an entire rewrite on the pcm? Sometimes that helps with the TCC issue. You mention the trans has 28K on it, is this original miles or was it rebuilt? What parts replaced if rebuilt? Was the pressure control solenoid replaced?

Have tried a full rewrite, but didn't help. The mileage on the trans. is the original milage, not rebuild.

If it is original miles then I would lean on either some internal issues causing debris to collect in the valve body / tcc and boost valve area or you just have a bad pressure control solenoid. The mileage doenst mean it should be fine. Some last a long long time and some do not, especially when you are making more power than stock.

Originally Posted by 19SE92

Monte0 Pm me with the complete list of what the cars doing and I'll get ahold of a trusted trans builder that i know and see what he says to do.

What in the hell do you mean 'trusted trans builder'? Do you know anything about Trannyman? Do you know anything about his qualifications, experience, reputation? How about you step up to the plate here and tell us just who this 'trusted trans builder' is. If he is so trusted and has such a great reputation Im sure he would have no problem you posting about him here.

You have crossed the line bud. You are digging your grave and Im gathering the shovels to help you out. Keep it up and I'll find a backhoe and expedite the ordeal.

Originally Posted by Trannyman95

If it is original miles then I would lean on either some internal issues causing debris to collect in the valve body / tcc and boost valve area or you just have a bad pressure control solenoid. The mileage doenst mean it should be fine. Some last a long long time and some do not, especially when you are making more power than stock.

Well here's the weird part then, it's acting like the original trans did when I bought the car (slow lockup, hard time staying locked, only acts up after the trans/engine is fully warmed up).

Also, when I bought the car at 70,000, it already had a GM reman the previous owners purchased that was only a year old. The problem dosent show quite as bad as when it's not at full operating temp either. It also seems to affect my regular gears after driving for a few hours, for example the shifts get alot lighter/softer and performance decrease.

Originally Posted by Reptile

That right there was the first thing that popped in my mind. I had the same issue after it was warmed up, and especially when the TC locked up at highway speeds.

It eventually got so bad that it would buck and kick while downshifting like coming to a stop.

Wouldn't WOT be affected then? Thats the only time it really dosent show any noticable issues at all. Seems to be at 1/2 and lower of the throttle range.

At WOT your pressure control solenoid is near turned off, especially if you have done a lot of tuning for firmer shifts. The solenoid causes a majority of its problems during in town driving after warmed up. Why both transmissions acted the same is pretty odd, but all in all they are both stock transmissions except for your new one having a shift kit which does not raise line pressure or effect TCC operation. A bad or dirty maf sensor can also cause low line pressure as it is related to trans line pressure to an extent so check that out also. Are you positive that your pcm is set up correctly for the 3.29 gears? If anything is off a little it will cause all sorts of problems with shifting and TCC operation. This may be something that just needs an good honest diag from a trans shop by hooking up a pressure gauge and scanner and going for a drive. Sometimes problems like this are just too difficult to have an easy answer and requires personal attention.

Originally Posted by Trannyman95

At WOT your pressure control solenoid is near turned off, especially if you have done a lot of tuning for firmer shifts. The solenoid causes a majority of its problems during in town driving after warmed up. Why both transmissions acted the same is pretty odd, but all in all they are both stock transmissions except for your new one having a shift kit which does not raise line pressure or effect TCC operation. A bad or dirty maf sensor can also cause low line pressure as it is related to trans line pressure to an extent so check that out also. Are you positive that your pcm is set up correctly for the 3.29 gears? If anything is off a little it will cause all sorts of problems with shifting and TCC operation. This may be something that just needs an good honest diag from a trans shop by hooking up a pressure gauge and scanner and going for a drive. Sometimes problems like this are just too difficult to have an easy answer and requires personal attention.

What about the TPS? I do have a extra set of TB sensors I could swap out and try.

As for the 3.29's, I have
Calculated_Pulses_Per_Revolution = 25
Drive_Sprocket_Ratio = 1
the other table is pretty much for the tire size, but since my car is a oddball (97.5) it has a different spec. then the other years.
If my shift tables are off just a touch, could this be it too? I can look them over too.
Besides that I'm going to drop the pan again to see if everythings ok this weekend.

One other thing, when the trans was filled after installing last fall, it was filled half with dex. 3 and half dex. 6. Reason being I ran an out of fliud so went to get more and no one had dex.3 so I had to mix the two together. On the bottle it said it was ok to mix, which I wasn't too keen on. What do you think?

Mixing the two fluids is fine and right on the bottle it says it is backwards compatable. As far as your shift tables you must make sure that you arent trying to turn on lockup at or before the mph that the shift into each gear occurs, so check that out closely. I dont use DHP tuner so I dont know what to offer for advice on your settings because the tables are different for HPTuners, which is what I use

OK, thanks Trannyman for the help. I'll check everything out and get back too you if I find out wth is up

Ok, did find some things that were not correct in my trans tables, mainly in the cruise and urban tables, but their was also a problem in the perf. table at about 15-20% throttle. Flashed and drove it this morning and it seems to be a tad better, but once it warms up it still acts up. Thier was one other symptom that I forgot to mention, the trans takes around 4-5 min. to go into lockup in the morning and it feels sluggish too.

I did notice something though while driving slow getting a coffee today, the trans actually whines a tad in drive but only crawling very slow(2-4 mph). Also, their was one other thing. You know the top electrical connection on the trans, is that the same pin-out on 97.5 and all the other years of 4T65E-HD trans.?

The delayed lockup is normal opperation in the morning or when cold. TCC is dissabled until the trans reaches a certain temp and varies a little between years, but is roughly around 110-120 deg F engine temp. Trans whining is sometimes normal depending on how loud it is, and making 100% that it is not an engine noise as many accessories on the front of the engine make similar noises and often blamed on the trans but you dont hear it as the car moves faster as wind and road noise cancel them out. 97-02 transmissions for W-body cars are interchangeable electrically and there is nothing special or different for the 97- .5 year range. Does the whine noise go away warmed up or is it always present? Im still leaning towards a poor operating pressure control solenoid but again without seeing the car in person with a scanner and pressure gauge its hard to pinpoint problems such as yours. Has this trans always acted like this the entire 28K miles or is this something that just popped up / got worse over time?

Originally Posted by Trannyman95

Does the whine noise go away warmed up or is it always present? Im still leaning towards a poor operating pressure control solenoid but again without seeing the car in person with a scanner and pressure gauge its hard to pinpoint problems such as yours.

The whine isn't present until it gets warmed up. And it's definitely the trans. If you put the car in park the whine goes. Is their anything in the DHP tuner I can scan that would shed some light on the problem? Is their a way to check the solenoids in the trans. at the electrical connector? (resistance reading?)

Originally Posted by Trannyman95

Has this trans always acted like this the entire 28K miles or is this something that just popped up / got worse over time?

I got the trans. with 20,000 on it, and yes the miles I drove it it has done this. But also , the original trans. did the same before when I purchased the car. Only thing it didn't do was whine.