Exceeding Redline In 1998 Trans Am With Automatic Transmission?
09-17-2013, 08:18 PM
#22
Staging Lane
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08-30-2014, 07:42 AM
#23
On The Tree
I have a 1998 Trans Am with an automatic transmission. I've been wanting to see what my 0-60 and 1/4 mi. times are, but I was told by the dealership that the 1998s are not equipped with a rev limiter. I realize I can blow the transmission by downshifting at high speed, but in a 1/4 mile or 0-60 time test, there's no reason I'd ever need to downshift -- only upshift. So my question is this: If I leave my automatic in high gear at the start line, and then stomp on it when the flag goes down, will my transmission ALWAYS upshift to the next gear before I reach redline, no matter how hard I drive it? I've looked all over your forum for the answer, but I can't find it. My fear of overreving my engine with no built-in protection, and the huge cost involved if I do, is what's keeping me off the track. I'd appreciate it if only members with extensive background in racing and/or automatic transmissions answer this question. In other words, gearheads 
not boneheads. 
Thanks!
not boneheads. Thanks!Don't EVER go there again, find someone in your area that specializes in LS motors/tuning and forward all issues to him. DON'T EVER let a dealer work on your car PERIOD. Not only will you pay "top dollar" for labor & parts, but they are a bunch of hacks trying to finish a job quicker so they can bill more hours. Most techs are paid by the job, not hourly or by salary, so if the repair on your car is a "2 hour" repair according to the "book" and he can finish it in 45 minutes, he still gets paid for 2 hours work.. so he does not give 1 **** about doing it correctly, only as fast as he can... so FYI, NEVER GO TO ANY DEALER EVER!!! Are we clear on this now!!!!! I'll send you some reputable LSX guys from your area if your location is listed in your sig.!!!
08-30-2014, 07:44 AM
#24
On The Tree
I have a 1998 Trans Am with an automatic transmission. I've been wanting to see what my 0-60 and 1/4 mi. times are, but I was told by the dealership that the 1998s are not equipped with a rev limiter. I realize I can blow the transmission by downshifting at high speed, but in a 1/4 mile or 0-60 time test, there's no reason I'd ever need to downshift -- only upshift. So my question is this: If I leave my automatic in high gear at the start line, and then stomp on it when the flag goes down, will my transmission ALWAYS upshift to the next gear before I reach redline, no matter how hard I drive it? I've looked all over your forum for the answer, but I can't find it. My fear of overreving my engine with no built-in protection, and the huge cost involved if I do, is what's keeping me off the track. I'd appreciate it if only members with extensive background in racing and/or automatic transmissions answer this question. In other words, gearheads not boneheads. Thanks!
not boneheads. Thanks!
09-02-2014, 09:52 AM
#26
TECH Fanatic
09-03-2014, 05:30 PM
#27
TECH Enthusiast
If your car came with the factory with the lower rated T rated - 118 mph tires (such as a base Formula or Z28) you will also have a fuel governor limit set at approx 115 mph.
10-25-2017, 06:39 PM
#28
Digging for best shift points... Avid Old Thread Reader My advice would be to never return to that dealership for information such as this ever again. They are completely wrong. Rev limit for your '98 is set to 6200rpm in the stock PCM.
The 4L60E is controlled by the PCM, and it will prohibit manual downshifts above certain speeds for certain gears (if you manually put the shift level into 1st gear at 100mph, it will not allow this to acutally happen within the transmission).
Yes, assuming that there is nothing wrong with your transmission causing it to slip or shift late, etc. And assuming that you have stock tuning or aftermarket tuning that has the proper relationship between shift points and the rev limiter (you don't want to set the rev limit and shift point to the same rpm, there needs to be a window between the two - the stock window was 200rpm [shift point at 6000, rev limit at 6200] but you can usually get away with as little as a 100rpm window if your trans is in excellent working order).
Unlike a manual trans car, you can't mechanically overrev a 4L60E car, so unless you remove the rev limiter via tuning, this should not be a concern.
Well, I've owned four of these cars (LS1/4L60E combos), and in those cars I've owned four stock 4L60E transmissions and two "built" 4L60E transmissions. One was tuned by a shop, and the other was tuned by me. I've raced with both the stock and built versions of these transmissions.
Hopefully my experience/resume is good enough.
The 4L60E is controlled by the PCM, and it will prohibit manual downshifts above certain speeds for certain gears (if you manually put the shift level into 1st gear at 100mph, it will not allow this to acutally happen within the transmission).
Yes, assuming that there is nothing wrong with your transmission causing it to slip or shift late, etc. And assuming that you have stock tuning or aftermarket tuning that has the proper relationship between shift points and the rev limiter (you don't want to set the rev limit and shift point to the same rpm, there needs to be a window between the two - the stock window was 200rpm [shift point at 6000, rev limit at 6200] but you can usually get away with as little as a 100rpm window if your trans is in excellent working order).
Unlike a manual trans car, you can't mechanically overrev a 4L60E car, so unless you remove the rev limiter via tuning, this should not be a concern.
Well, I've owned four of these cars (LS1/4L60E combos), and in those cars I've owned four stock 4L60E transmissions and two "built" 4L60E transmissions. One was tuned by a shop, and the other was tuned by me. I've raced with both the stock and built versions of these transmissions.
Hopefully my experience/resume is good enough.
1) What is the Advantage of putting it in 3rd instead of 4th (OD) ??? Yes, I plan on some 1/4 mile use end of next week (Nov.3rd).
2) So, very similar car/set up as the OP, I do have 3.42's with my 4-spd Auto, and would like to set my shift points for max 1/4 mile performance; stock drivetrain w/free mods (See Signature). Looked and still haven't found the best RPM for 1st to 2nd, and 2nd to 3rd shift points for drag racing. And then I'll adjust Rev Limiter from stock 6,200 - currently have it at 6250, just in case.
Thanks!
Mike
10-25-2017, 06:51 PM
#29
TECH Junkie
When drag racing 1/4 mile on a stock 4l60e leave the shifter in Od/4th.
When keeping it in 4th it prevents the overruns from being applied.
When putting it in D3 the overruns will be applied while the 2-3 shift is happening in turn diverting much needed fluid from the 3-4 clutch pack in order to apply the overruns...... not ideal.
You can add a Sonnax 2-3 shift valve that will keep the overruns applied in 1st, 2nd and 3rd when D3 is selected. This also helps support the forward sprag and is not diverting fluid during the 2-3 shift
When keeping it in 4th it prevents the overruns from being applied.
When putting it in D3 the overruns will be applied while the 2-3 shift is happening in turn diverting much needed fluid from the 3-4 clutch pack in order to apply the overruns...... not ideal.
You can add a Sonnax 2-3 shift valve that will keep the overruns applied in 1st, 2nd and 3rd when D3 is selected. This also helps support the forward sprag and is not diverting fluid during the 2-3 shift
10-25-2017, 08:21 PM
#30
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Best to start a new thread with these questions, should be done in the auto trans section.....
