Would a slipping converter clutch cause the engine to rev to 3500RPM at 60 MPH in 4th gear? I would think that if the 'puter was unlocking the converter that the engine would not rev without accelerating. Shouldn't the car accelerate, just with a slightly higher RPM?

The car is almost 100% stock.

Speaking of datalogging. What would be the least expensive way to do this? If I have a laptop, how cheaply can I get away with interfacing it with my car?

 

if you like driving in 3 (or D) then do it. if you feel like leaving it in OD, then do it. everybody has some stupid reason why to or not to do this or that but in this case i don't believe any of it.

 

If you're talking to me, I prefer to drive in OD. I drove it that way for about 1000 miles.

Now I can't unless I'm cruising on the highway over 65 mph or it slips like a ****. For example, if I'm going 40 and the trans shifts to 4th, I can't even hold that speed without the trans slipping. I have to downshift back to 3rd until I reach 55-60.

If you're not referring to my problem specifically, then I have no comment.

 

nah man- i was reffering to the post in general. sorry for the confusion.

 

Guys did you ever hear of tranny temperature. That is why you would leave it in OD/4th/drive the highest selection before neutral. If you drive your car in 3rd or what every you call it the tranny will heat up and the car will rev higher and use more gas. The tranny braking that you call it is the tranny slowing the car down because it wants to go into overdrive if you were ever in a manual car you would know that if the driver does not shift out of a gear the car will slow down becase of the tranny slowing the car down, which causes heat and can hurt your tranny. I personally never had my torque converter lockup in a gear other than overdrive that is why it locks up so you can get a cooler tranny and better gas mileage why would it lockup in 3rd when you have another gear to go I never felt it lock up stock or now with my vig 3200. leave your car in the highest selector before neutral and let it be. If you think you are cool and want to manually move the shifter remember that no matter where you shift at the car will still shift at the designated shift point, these cars are not like the old irocs and vettes where that made a difference . If you want to impress a girl or bounce with a manual car then you can but the shifter down a gear but otherwise leave it alone. BTW if you are making those long highway runs and are nervous about the tranny blowing up just get a tranny temp gauge and rely on that. A tranny temp gauge is priceless if you are scared about blowing up your tranny.

 

That was really fun to read. I think I looked it over three times to figure out what you're trying to say.

Try spacing out some of your sentences. It makes it easier for others to read your ideas and opinions.

As far as which setting to drive in... the primary concern (and the topic of the thread) is what selection to use when "getting on it", or when driving at full or near full throttle. It may still be smarter in the long run to pop the selector into D for Camaro or 3 for Firebird if you know you're about to punch the throttle. It will save some stress on the 3-4 clutches by not having to downshift in or out of 4th gear.

Manually shifting through all the gears has been universally rejected by every F-body fan, so it must be bad.

When driving around in general, OD is better...but that should be obvious.

 

I always keep mine in 4th(od) unless i'm in heavy traffic that's not going above 40mph. I perfer to have my converter lockup when in 3rd, not at wot, just part throttle. With the proper tuning of shift points/lockup you can leave it in 4th all the time. I've gone 3-4 WOT about 6 times and my trans is still holding up with a 3200 stall at 40k.

On another note, gm intended the transmission to always be left in 4th(od), they wouldn't expect customers to shift between 3rd and 4th depending on conditions.

 

Hi guys, I have an 11 second 91 GMC Syclone with the 700-R4 "4L60" original tranny and stock converter, I know it is the same as the 4L60-E minus the electronics. This truck has seen a TON of WOT, probably 2000-3000 quarter mile passes altogether (no ****) if you add up all my timeslips plus street pounding.

I always cruise in D (3rd) and shift into OD (4th) on the freeway. When I race I always click into 4th gear at 4500 RPM which is about 96 MPH (low revving truck). Every single full pass I ever made (street or strip) I have gone 3-4 at WOT. It is not the fastest shift, it feels sort of soft but was always consistent and solid and the tranny never missed a beat. Plus when I was going max-effort I always engaged TCC Lockup switch which forces TCC lockup as SOON as the tranny hits 2nd gear. Therefore it is locked the rest of the way and through the 2-3 and 3-4 shifts. I have probably 500-700 passes with TCC lockup engaged. My stock TCC never wore out, just stopped dropping as much RPM but a 7500-mile ATF flush always fixed that right back to normal. When I drive normally and the ECM engages WOT TCC Lock at 69MPH in 3rd gear, it always feels like a small "50hp boost" of power, the truck literally surges forward and the passenger can notice.

Here is a video of one of my passes: http://s95370645.onlinehome.us/syclo...pt51_run12.mpg you can easily hear the shifts by the engine tone, at the 1/8 mile point you can hear the shift into TCC-Locked-3rd really bring the engine RPM down, and then you can hear the shift into 4th well before the ET lights illuminate.

Now here's the real kicker; I raced my truck at Road America 4 mile high speed road course last year and the tranny survived! Here is a photo: http://popularhotrodding.com/events/...speed_11_z.jpg

I ran 7 sessions of 20 minutes a piece, that is nearly 200 miles of WOT racing, and you can only imagine how many 3-4 WOT upshifts I punished this tranny with, the tranny temp gauge was right at the max 260 (just a hair under), top speeds 125 MPH (remember my 3rd gear only lasts until 96 MPH, and I turned the boost way down for this event cause I thought I'd blow the bottom end not being able to constantly monitor Knock retard like I do drag racing.)

So my point is to offer some evidence to prove it is possible for the "4L60" to last under power doing 3-4 WOT shifts and TCC WOT Lockups. My truck probably makes 450-500HP and 600FT-LB torque.

For what it's worth, the truck ran 13s and 12s most of it's life; I just recently got it into the 11s and I lost engine braking (small metal fragments in the pan, feels like it's in Neutral when you let off the gas or coast-down) and about 6 months later I pulled the trans and currently am installing a built trans & high stall TC.

Hope you guys found this interesting,

Josh Straub
91 GMC Syclone

 

your truck sounds outstanding! love that turbo sound.