Built transmission and shift time?
- Thread starter skintback
- Start date
I honestly think it depends on OS...some schedule differently than others. So I've found anyhow
If the tcm is looking at output speed and the tc is not locked and you are pushing the stall higher the engine rpm will be higher than normal for any given output shaft speed. I have dealt with this with 4r100's and 4l80's with the pcs controller.
I am not sure exactly how the tcm in these trucks is calculating stuff and how much consideration is given to engine rpm sent over the can bus.
I think it makes sense though that the tcm is biased to output speed based on known results in higher powered trucks with looser converters.
Does a lockup box help keeps the shifts consistent with the commanded shift points in the calibration?
I am not sure exactly how the tcm in these trucks is calculating stuff and how much consideration is given to engine rpm sent over the can bus.
I think it makes sense though that the tcm is biased to output speed based on known results in higher powered trucks with looser converters.
Does a lockup box help keeps the shifts consistent with the commanded shift points in the calibration?
You have it all wrong. Get the Allison book on how it operates.
I must say it's been nice not having you here for the last 3 months.
As stated above, there may be a disparity between when the tcm commands a shift at a given mph, and the mph at which the shift is actually occurring. In order to try and see if changing the shift speed (mph) helps your truck, you just have to log vss and commanded and actual gear selection to see if it matches what the values in those tables. If it doesn't, change the values to what you're seeing in the log and log again. If the actual shift mph is closer to what the tcm is commanding then you can guess which direction to go from there.
Update: i went ahead and pulled the trans out and the c3's are deep fried they were set at .070 and c1's were shedding bad i set them to .090 and they were .153 not burt though everything else looked like new i have about 20k on the build about a year old all raybestos
Any ideas why this happened?
Any ideas why this happened?
The early Raybestos C1's ( outside tooth only ) shed their lining quickly because they were not compressed at the factory properly IMO. My Raybestos C1's in my LML failed after 1 year ( 5K miles).
If the C1's are not holding in 3rd you will lose the C3's in short time. Which C3 clutches were you using?
Here is some pictures. The color difference in the c1's EX/IN were like that from new i didn't think anything of it. you can now rub clutch material off the EX spline with your fingers
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I have only heard of their C1s delaminating in some cases, but luckily haven't had any do it myself. I'll bet if we went back and checked every pack we installed in their first 3yrs of use they would be loose like yours Sonny. Every one I have checked has been. They started shipping the updated pack late summer of last year if I remember right. For your truck, as I recommended before, I would use the Alto carbonite C1s. They are and have been a great clutch IMO
So my raybestos c1's I bought back in December of 2014 do not suffer from this issue?