"HEY GRUMPYVETTE!
newbie here trying to determine if my 1988 C4 automatic is shifting correctly. Can anyone tell me at what mph(s) (approximately) the car should change from gear to gear? Also, does the C4 (1988) have an overdrive feature and, if so, how is it activated? Thanks!"
viewtopic.php?f=71&t=555
if you have a 1988 corvette you NEED A SHOP MANUAL
http://www.csgnetwork.com/rpmcalc.html
1st 3.06
2nd 1.63
3rd 1.00
overdrive 0.70
we need to know if the rear gears been changed (WHAT THE REAR GEAR RATIO IS)
the car naturally shifts at lower rpms under light loads, generally at under 2500rpm-3000rpm under light loads (GENERALLY SHIFTING NEAR 2000RPM under light loads, at normal street driving conditions with a stock converter )and at about 5500-5700rpm rpm under WOT
the rear gear will determine the MPH that occurs at,
and yes theres an OD gear on your cars auto trans, that will activate if its operating correctly simply by exceeding 3500rpm in light load cruise
this would be about typical
1st 0-
2nd shifts at 17mph
3rd shifts at 37 mph
4th shifts at 67 mph
http://auto.howstuffworks.com/1988-corvette1.htm
http://www.corvettefever.com/howto/4686/index.html
Thanks
Amazing! Those are the EXACT mphs that my car shifts!
Thank you!
I have one additional question: At highway speed, say 55-60mph or so but BEFORE the shift to 4th, if I am accelerating and let off the pedal, the car "drops" into a smooth, cruise mode -- no more building RPM or revving engine. It feels like I am in overdrive or auto pilot or something -- lower engine noise, smooth ride. What's happening? Thanks
I will get a shop manual. I am not experiencing any shifting problems now. What I thought was a shift problem was actually the OD kicking in before the shift at 67mph (4th). I would drive along with the engine speed/sound building, but I would not have reached 67 mph. When I would let off the pedal, the car would ease into a cruise mode -- and I thought the car was shifting after acceleration -- that it wouldn't shift unless I let off the gas because it was hanging up or sticking. Once I took it out and could get the speed up over 65, I found 4th gear at 67 -- then ran through all gears and determined when the car would shift. I then realized what I was feeling when I removed my foot from accelerating was not a late shift into 4th but actually OD. Thanks for helping me. This is obviously my first Vette, and I don't know anyone else who owns one. I appreciate this forum.
yes, your in OD/cruise, the 700r4 converter locks to the engine under low load cruise conditions and yeah! before you ask stomping on the throttle drops it back into a lower gear
newbie here trying to determine if my 1988 C4 automatic is shifting correctly. Can anyone tell me at what mph(s) (approximately) the car should change from gear to gear? Also, does the C4 (1988) have an overdrive feature and, if so, how is it activated? Thanks!"
viewtopic.php?f=71&t=555
if you have a 1988 corvette you NEED A SHOP MANUAL
http://www.csgnetwork.com/rpmcalc.html
1st 3.06
2nd 1.63
3rd 1.00
overdrive 0.70
we need to know if the rear gears been changed (WHAT THE REAR GEAR RATIO IS)
the car naturally shifts at lower rpms under light loads, generally at under 2500rpm-3000rpm under light loads (GENERALLY SHIFTING NEAR 2000RPM under light loads, at normal street driving conditions with a stock converter )and at about 5500-5700rpm rpm under WOT
the rear gear will determine the MPH that occurs at,
and yes theres an OD gear on your cars auto trans, that will activate if its operating correctly simply by exceeding 3500rpm in light load cruise
this would be about typical
1st 0-
2nd shifts at 17mph
3rd shifts at 37 mph
4th shifts at 67 mph
http://auto.howstuffworks.com/1988-corvette1.htm
http://www.corvettefever.com/howto/4686/index.html
Thanks
Amazing! Those are the EXACT mphs that my car shifts!
Thank you!
I have one additional question: At highway speed, say 55-60mph or so but BEFORE the shift to 4th, if I am accelerating and let off the pedal, the car "drops" into a smooth, cruise mode -- no more building RPM or revving engine. It feels like I am in overdrive or auto pilot or something -- lower engine noise, smooth ride. What's happening? Thanks
I will get a shop manual. I am not experiencing any shifting problems now. What I thought was a shift problem was actually the OD kicking in before the shift at 67mph (4th). I would drive along with the engine speed/sound building, but I would not have reached 67 mph. When I would let off the pedal, the car would ease into a cruise mode -- and I thought the car was shifting after acceleration -- that it wouldn't shift unless I let off the gas because it was hanging up or sticking. Once I took it out and could get the speed up over 65, I found 4th gear at 67 -- then ran through all gears and determined when the car would shift. I then realized what I was feeling when I removed my foot from accelerating was not a late shift into 4th but actually OD. Thanks for helping me. This is obviously my first Vette, and I don't know anyone else who owns one. I appreciate this forum.
yes, your in OD/cruise, the 700r4 converter locks to the engine under low load cruise conditions and yeah! before you ask stomping on the throttle drops it back into a lower gear