Top Speed with 3.73's

[blackfire93]

Here's a table of rpm vs. mph for the 4L60/4L60E in 3rd anf 4th (O/D) gears:

So how do I get it to shift into 4th (O/D) and achieve a higher top speed than just 117? Or will it not shift into O/D because it's floored?

[Injuneer]

Have you tried shifting it manually from "3" to "D"? I'm no expert with automatics, but I believe is should shift into 4th (O/D) even if your foot is on the floor. With it in "D" will it shift if you lift slightly?

You might want to ask Ion if there is anything in the program that would cause it to act the way it is.

[Craig 94 TA GT]

This may not be the answer but how long has it been since you changed your plugs and wires? I had such old plugs several years ago, it did the same thing. When you keep it on the floor, maxing out 3rd, it will seem to keep tapping on the rev limiter, but it's actually sitting at maybe 5600 or lower RPM due to weak spark.
With mine too, the tach looked like it was right at 6000 bouncing. In actuality, it's not hitting the RPM shift point at WOT, thus creating an effect of a fake rev limiter. For me, though, it did it in all gears. However, once I changed the plugs, wires and opti, only the top end of 3rd was giving me problems. After replacing the ICM, the problem seemed to disappear. So generally speaking, if you've run out of ideas, it may be spark related

[blackfire93]

I have changed my plugs within the last 7k miles. I haven't changed the wires since I bought it, Which was like 12k miles ago. They're probably still stock wires and need changed.
Yes, I have emailed Ion and asked him about the problem. He said that with a 4L60 it couldn't be the programming because it's non electric. Which is what I thought but had to ask anyway. Ion thought that it's probably a problem with the transmission. He might be right, but I hope he's wrong. If I do need the transmission rebuilt one of these days I'm switching over to a t56. I'll try shifting it from 3 to D sometime. I'm just kinda leary about the cops so it might be a while. If that doesn't work I have also thought of letting off and slowly making my way past 110 and on my way to 125 in 4th. That will take a longer stretch of road though. To everyone who replied, thanks for all your help

[DeWynter]

I thought that GM auto trans would not allow you to shift into O/D at WOT only at 3/4 or less? I know this to be a fact for 3rd gens and people often have this removed by programing or some other way on non-computer controled cars. Could this also be the case for 4th gens? I know this is also in effect on many trucks.

[blackfire93]

I have found the answer to my problems.

Re: Paging Frank about 1993 4L60 problem

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Sonnax "full throttle upshift" valve and sleeve.

Frank
CPT
__________________
http://www.cahallperformancetransmissions.com
Purple Pearl 93 Z...12.0 @ 112.35 MPH 1.67 60 ft. N/A
Orange '70 Camaro...10.83 @ 124.5 MPH 1.52 60 ft. N/A
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Buildsheet
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New 355

[roastm]

i don't mean to pick sides but freds right back in the day my chevy had 323's and thats exactly what my lap top ( lt1 edit / scanner ) said i was doing

[joe ws6]

http://www.xse.com/leres/bin/gearrat...mference=78.35

May help

[ConElite]

what would my rpm's be at on the highway (between 75-85).

Somewhere around 1600-1900 at 75 i think.

[Z Ya Later]

Mine hits the regulater and loses power at 115 in OD also... shift it into D and youll get it up to 135-140 after that it doesnt increase much but you dont max out on the RPM's... i think its at like 4,000? 4,500? Been a while since ive had that much open road.

Im thinking of doing the same thing... what would my rpm's be at on the highway (between 75-85).

In OD, you'll be looking at 2600-2800 for 75-85, roughly.

Had it covered boss