please help with transmission problems. slipping in all gears under hard acceleration
06-28-2010, 01:42 PM
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please help with transmission problems. slipping in all gears under hard acceleration We recently put a used transmission in my buddy car (97 C5 vette) that we got from another member on on here that came from a low mileage (30k miles) wrecked 2002 corvette. From what he said teh transmission work great in that car.
What the trans is doing is under hard acceleration it slips bad in first and second gear. We also installed a new yank sy3500 converter in the car. His car previously had a 3400 stall in it and is tuned for the stall but his transmission recently started slipping 3rd to 4th gear which is why we pulled it and swapped to this one. Is there any thing we can look at to figure this out or is it basicly just a bad transmission? I really haven't sen any that slipped first and second its usually the third to forth. I have hp tuners if there is any thing we should check in the tune but you will have to be pretty specific as I just got the software and really don't know that much about it.
Also don't know if there is a difference but the car is a 97 and transmission is from a 2002 is there any difference in that?
What the trans is doing is under hard acceleration it slips bad in first and second gear. We also installed a new yank sy3500 converter in the car. His car previously had a 3400 stall in it and is tuned for the stall but his transmission recently started slipping 3rd to 4th gear which is why we pulled it and swapped to this one. Is there any thing we can look at to figure this out or is it basicly just a bad transmission? I really haven't sen any that slipped first and second its usually the third to forth. I have hp tuners if there is any thing we should check in the tune but you will have to be pretty specific as I just got the software and really don't know that much about it.
Also don't know if there is a difference but the car is a 97 and transmission is from a 2002 is there any difference in that?
Last edited by bigfatls6; 06-28-2010 at 02:58 PM.
06-28-2010, 07:17 PM
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The SY3500 is a very low STR which will probably feel
kind of "stretchy" compared to higher-STR converters.
In HPTuners scan tool, log the input & output shaft speeds,
Trans Current Gear and TCC Slip RPM.
Export the logs to .csv, and in Excel make yourself new
columns of (InShaft/OutShaft) and ratio(TransCurrentGear),
and one of (In/Out)/ratio. This last should look like 1.000
except right at the shifts. Deviation means fricton slip
(trans issue); hanging tough means it's just perception
of the SY3500 characteristics.
If this is too muddy, attach a log file and I'll try and show
you what I'm talking about.
kind of "stretchy" compared to higher-STR converters.
In HPTuners scan tool, log the input & output shaft speeds,
Trans Current Gear and TCC Slip RPM.
Export the logs to .csv, and in Excel make yourself new
columns of (InShaft/OutShaft) and ratio(TransCurrentGear),
and one of (In/Out)/ratio. This last should look like 1.000
except right at the shifts. Deviation means fricton slip
(trans issue); hanging tough means it's just perception
of the SY3500 characteristics.
If this is too muddy, attach a log file and I'll try and show
you what I'm talking about.
06-29-2010, 10:41 AM
#5
Losing the 3-4 clutch pack is common on a stock unit, and even on a lot of built ones that were not done right. What is the condition of the fluid? Do you see clutch/band material? It will be blackish gray in color when you wipe off the stick. If the pan is off, and you see clutch/band material away from the pan magnet covering the bottom of the pan, then then transmission is history. The transmission will then need to be taken out and see what went away.
06-29-2010, 10:50 AM
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We have a lift so its prett easy. Just pull the plug on the side and add fluid until it come out then start the car and put it in drive and finish filling it until it runs out of the plug hole.
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06-29-2010, 01:01 PM
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So, the transmission you're having problems with has 30,000 miles on it and worked fine in the car it was taken out of.....
Now it doesn't work.
Slip in 1st and 2nd? almost sounds like the new 3500 converter you put in it is making it start out in 3rd, a common problem. It could even be a blown fuse and the trans isn't getting power.
OR can you feel 3 gear changes?
You could load up the table below and see whats going on.
Or you could just check the fluid a few more times, assume it's fried, pull it out for another trans just to have the same problem.
Did you flush the cooler between swapping the bad trans and good trans?
Now it doesn't work.
Slip in 1st and 2nd? almost sounds like the new 3500 converter you put in it is making it start out in 3rd, a common problem. It could even be a blown fuse and the trans isn't getting power.
OR can you feel 3 gear changes?
You could load up the table below and see whats going on.
Or you could just check the fluid a few more times, assume it's fried, pull it out for another trans just to have the same problem.
Did you flush the cooler between swapping the bad trans and good trans?
