eran tomer
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Doing an ls swap with psi harness on 95 k2500 suburban. The harness has iss and vss plugs. I understand that the iss is the front sensor, isn’t it? But there’s no rear sensor on the tranny. So where does the vss plug go?
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In '94 they started putting the vss in the Tcase on most 4WDs though there were some that still had it through '96...Doing an ls swap with psi harness on 95 k2500 suburban. The harness has iss and vss plugs. I understand that the iss is the front sensor, isn’t it? But there’s no rear sensor on the tranny. So where does the vss plug go?
Where else would the VSS go on a 4WD but in the transfer case? My '88 K1500 has the VSS in the transfer case.In '94 they started putting the vss in the Tcase on most 4WDs though there were some that still had it through '96...
Good question as I'm not exactly sure how GM managed vehicle speed back then in those early 90s 4wd 4L80Es and unfortunately it's been forever since I did an early 4x4 4L80 (91-93 vintage). But last one I do remember doing was a 92 4wd and it had both speed sensors installed and the reluctor on the output carrier (rear planet) for the sensor to read. Its also possible there were three speed sensors (ISS, OSS and VSS) including the one in the TC which would be the VSS, if so. I never see the vehicles themselves so wouldnt have had the opportunity to view the entire set up.Where else would the VSS go on a 4WD but in the transfer case? My '88 K1500 has the VSS in the transfer case.
On any transfer case with a low-range, you'd need the VSS able to see actual output shaft/driveshaft RPM, to get a proper speed reading no matter which "range" the transfer case was in.
Or do some of them use the DRAC to adjust the pulse count based on which range the transfer case is in?
THAT I'd believe, although I didn't know they were using input and output sensors that early.Its also possible there were three speed sensors (ISS, OSS and VSS) including the one in the TC which would be the VSS
Yea its an interesting question...hopefully I can find out more in the next few days and relay here, unlesss someone else can chime in sooner with the facts on those early 4x4 speed sensor set ups...THAT I'd believe, although I didn't know they were using input and output sensors that early.
In my research on DRACS they only have one VSS input and it comes from the driveshaft.Where else would the VSS go on a 4WD but in the transfer case? My '88 K1500 has the VSS in the transfer case.
On any transfer case with a low-range, you'd need the VSS able to see actual output shaft/driveshaft RPM, to get a proper speed reading no matter which "range" the transfer case was in.
Or do some of them use the DRAC to adjust the pulse count based on which range the transfer case is in?
no. drac uses a 40 tooth wheel usually in tail shaft or transfer caseIn my research on DRACS they only have one VSS input and it comes from the driveshaft.