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I did an LS swap with a 4l65 for a friend of mine on an early Jeep. He wants to keep the stock speedometer, so we did the 8k ppm vehicle speed sensor.
I have not been able to get the transmission to shift out of first gear.
I am out of ideas.
This is my set up.
2005 GMC Yukon Denali 6.0 4L65E 4X4
33 inch tires
3.54 gears
18 and 44 on the speed sensor gear.
Here is my hpt file.
Any ideas?
Use a Bluetooth OBD II adapter (inexpensive, maybe 15 bucks) and the free "Torque" app on your phone to see if the PCM is registering any speed. Use a helper in the passenger seat, this is a driving test.
My 4L60E had a bad VSS and would not shift. Why would it? It thought it was sitting still. A new AC Delco VSS for a 4L60E was about $35. Not sure for your 4L65E.
Rick
I monitored the output rpm and vehicle speed with my Snap On scan tool and both seem to be accurate.Quote:
Originally Posted by B52bombardier1
Just solved the same issue with a 1976 Sierra with a 5.3/4L60E with the OEM manual transfer case. Had a speed signal generator inline with the speedo cable. First got the scanner speed to match a gps, this is done with the "VSS Pulses Per Distance". Next log the output shaft RPM while driving. To calculate the trans mile per hour, do this; (trans output shaft rpm*60)/trans output revs per mile (which is 2,230.1949 in your tune)
So you need to get the trans mile per hour to match the vehicle speed in the scanner, if the trans mile per hour is low, lower the "Trans revs/mile" by the % error of the vehicle speed in the scanner.
Also look at you shift speed tables, your 1-2 is at 141 mph. What I did on the 1976 Sierra was to start with a stock tune, and change the tire size & gear ratio to what the truck has currently. Then copied all the shift speed & TCC tables to the modified tune.
Russ Kemp
Thanks Russ,Quote:
Originally Posted by Russ K
141 mph might be a little high for first gear lol.
I don't know how that happened. I will fix the shift tables and report back.
I don't know how my shift tables got corrupted. I went back to the stock file and modified what I needed to and it works great.
Thank you so much for catching the shift table issue.
Russ, can you help with this? we have an 89 K truck using transfer case with vss pass thru from Dakota Digital. Very similar to your Sierra with a manual transfer case. I have a digital gauge package so the speedo and tach all work from its own signal generator attached to the pass thru output cable drive. Redundant I know. The transmission shifts but I haven't looked at rpm while driving and a spreadsheet to compare the tune with actual speed. The speed output in scanner doesn't go above 5mph. mostly 3-4mph. We made changes to the Hardware >> VSS P./ REV - TRANS from stock 40 to an alternative VALUE 3.2773. It seems to shift about right but it's not my auto and about 2hrs away. I would like to get the speed to show in scanner for sure and know what my shifts are happening at. What value for trans Revolutions/mile and how to figure % error? I don't have the speed in scanner to know % it's off. If I change the pulse back to 40 will speed show up but incorrect calibration and just calculate error and adjust that trans revs/mile by % or is something else needed?Quote:
Originally Posted by Russ K
What did you mean about copying the speed and shift tables into the modified file? Are you calibrating that speedo with the stock gear ratio and then make another file to figure what the new gears would shift at then copy that info into the re-calibrated speedo file? I thought by setting the new gear ratio and then calibrating the vss / speedo the shifts would be where the tables are set at and changes to shift schedule would be correct? I really appreciate your support on the forum and look forward to your response..
I set the VSS P./Revs-Trans to 4.00. Next get the scanner speed to match a gps by adjusting the VSS Pulses per mile. Then adjust the Trans Revs/Mile to get the trans mile per hour to match the vehicle speed.
For the shift speed table, start with a stock file and just change the gear & tire to a stock file. Then use the resulting shift speed table for your 1989 truck tune file to get you started.
Russ Kemp
Wow, I hate to resurrect this but still have the same issue. The Scanner doesn't report any speed except transient ambient voltage It is shifting fine and GPS tracks well to speedometer but the ECM doesn't show speed in Scanner. There is no VSS in tail housing it only has the DD gear-driven pass-thru signal generator that generates the pulse needed for dash in transfer case from the original '89 but nothing to ECM. It is the 8K pulse generator. Do you know of a way to get a VSS into ECM from these DD parts? Thank you.