automatic transmission information

[TURBO200R4]

hi my name is herman. if you need info on automatic transmissions i would be happy to answer questions for you. i have worked on transmissions since 1966 and been in business since 1975. i have built a lot of racing trans. it seems lately all we work on is computer controlled trans. if the speedo quits the trans starts to malfunction. ect. when the fuel filter plugs up the trans won't shift under full throttle. i have learned so much on r3owners i thought i would try to give some info back.
hermans automatic transmissions tucson arizona 520-294-8717
herman

 

[Pres10]

I do have a question. My 1998 Cheverloet K2500 with the 7.4 Vortec engine and 4L80E transmission for some reason wants to instantly lock up the torque converter as soon as it shifts into 4th (overdrive).

When the engine and trans are warm it usually operates normally but when cold it wants to lock up the converter imediately after shifting to 4th. The torque converter will not unlock unless you push the throttle down far enough to cause a downshift to 3rd gear. Again the problem is much more prominent when the engine is cold. Once the engine warms slightly, if I shut the engine off and restart it will usually perfom as it should.

Should I be looking for a solenoid problem? The truck has 185,000 miles but has been well maintained.

 

[TURBO200R4]

I do have a question. My 1998 Cheverloet K2500 with the 7.4 Vortec engine and 4L80E transmission for some reason wants to instantly lock up the torque converter as soon as it shifts into 4th (overdrive).

When the engine and trans are warm it usually operates normally but when cold it wants to lock up the converter imediately after shifting to 4th. The torque converter will not unlock unless you push the throttle down far enough to cause a downshift to 3rd gear. Again the problem is much more prominent when the engine is cold. Once the engine warms slightly, if I shut the engine off and restart it will usually perfom as it should.

Should I be looking for a solenoid problem? The truck has 185,000 miles but has been well maintained.

It seems odd that it could be locking solid in 4th. in the oil circuit 2nd gear oil feeds that circuit and most of the time when the lu solenoid goes bad (stuck on) you can feel the truck shake when it goes into 2nd and lugs eng. the solenoids are cheep and if you try that you should also do both shift sol. the 2 shift sol have different brackets so you can't go wrong. the ttc sol dealer# 24210864.
your best bet is to have a trany guy to put a good scanner on it and see when the computer is commanding lu. also you can lightly touch brakes and that should kill lu. if the bushings in the front pump stator are wore out it will leak by and apply lu.
by using scanner you can tell if the computer is doing that or the prob. is in the trans.
keep me posted and i will try to help.
i have dial up service but i will try to check site this weekend
herman

 

[Pres10]

Herman,
Thanks for the help and insight to the transmission.
Sorry for the delay in responding, been working way too much.

I am sending you a private message.

John

 

[TURBO200R4]

bump

 

[R-III-R Turbo]

hi herman can we get a 6th gear for the rocket tranny please?

 

[TURBO200R4]

hi herman can we get a 6th gear for the rocket tranny please?

6 gears and a reverse coming right up of coarse it is going to be a foot longer

 

[ricochet]

I used to have a 2005 Grand Prix GXP that was the 5.3L V8 engine. It was the worst car I ever had as far as reliability was concerned. When I bought it (used) I was not disclosed that it had 4 transmission rebuilds. After I bought it, I started having problems... The issue was that when I would come to a stop at a traffic light or stop sign, I would lift my foot off the brake and proceed to press the gas pedal and the RPM's would shoot up but the car was not moving forward... randomly it would eventually just go THUNK and kick it into gear and cause the car to jolt forward... once moving, the car and transmission ran fine. This happened often enough that I eventually got fed up and asked my dealership to look into the problem. Of course, when the technician took the car out for a drive, he never found any issues in the way the car performed. He handed me small ODB connector that was attached to a little recorder that monitored my cars activity.

Then one morning I was exiting my underground parking, I had to drive up a tall angled ramp area to get onto the ground level.... when I accelerated up the ramp, same thing, revs up.. no go.. then CLUNK the wheels start spinning and off I go. The recorder revealed absolutely no information at all.

Eventually I had to give in and have my car go in for service for the who know how many'th time. It eventually had 2 seperate transmission rebuilds, and everytime it would be great for a few hours of driving, and then it would do it again. After a total of 6 transmission rebuilds, and no help from GM, I decided to say **** it and sell the car. Never been happier.

The thing that always bothered me was that no one had any idea or information on why these things happen. Not the master mechanic, not GM, no one. They just told me it was probably the "Clutch" or "Torque Converter" int the transmission but again, after 6 rebuilds, why would this happen? I have never been able to get a straight answer... if it wasn't for those problems, I really liked the car but it was too much hassle. Any ideas?

 

[TURBO200R4]

I used to have a 2005 Grand Prix GXP that was the 5.3L V8 engine. It was the worst car I ever had as far as reliability was concerned. When I bought it (used) I was not disclosed that it had 4 transmission rebuilds. After I bought it, I started having problems... The issue was that when I would come to a stop at a traffic light or stop sign, I would lift my foot off the brake and proceed to press the gas pedal and the RPM's would shoot up but the car was not moving forward... randomly it would eventually just go THUNK and kick it into gear and cause the car to jolt forward... once moving, the car and transmission ran fine. This happened often enough that I eventually got fed up and asked my dealership to look into the problem. Of course, when the technician took the car out for a drive, he never found any issues in the way the car performed. He handed me small ODB connector that was attached to a little recorder that monitored my cars activity.

Then one morning I was exiting my underground parking, I had to drive up a tall angled ramp area to get onto the ground level.... when I accelerated up the ramp, same thing, revs up.. no go.. then CLUNK the wheels start spinning and off I go. The recorder revealed absolutely no information at all.

Eventually I had to give in and have my car go in for service for the who know how many'th time. It eventually had 2 seperate transmission rebuilds, and everytime it would be great for a few hours of driving, and then it would do it again. After a total of 6 transmission rebuilds, and no help from GM, I decided to say **** it and sell the car. Never been happier.

The thing that always bothered me was that no one had any idea or information on why these things happen. Not the master mechanic, not GM, no one. They just told me it was probably the "Clutch" or "Torque Converter" int the transmission but again, after 6 rebuilds, why would this happen? I have never been able to get a straight answer... if it wasn't for those problems, I really liked the car but it was too much hassle. Any ideas?

FIRST of all that transmission when the atf is at the add mark it can be as much as 3 qts low i all ways recommend putting it above the full mark on this trans. if a trans is low on atf when u make a fast stop or go around a corner it will suck air and go into neutral.
the correct way to check would have been to have a pressure gauge on it while monitoring the epc (electronic pressure control). that trans should have 75 lbs pressure at idle if it drops below 50 psi it will go into neutral.
its impossible for me to say what the problem is w/o checking but it could have been a bad epc or a pressure loss in the circuit of the 1/2 band.

 

[TURBO200R4]

i have in the past seen people lose the checking stick and replace it with a longer one and this makes the trans low on atf. for checking purpose ONLY I WILL PUT a quart extra in it to see if it makes a difference.