Pocket

iTrader: (24)

Maybe Im thinking too much into this but oh well here goes

My project is stuck. SBC/TH350/0411 LS1 PCM

Im stuck on the VSS issue. Most TPI/TBI guys who run the TH350 either stick a 700R4 tailshaft on the TH350(9" tail only) and reuse their old VSS or buy a cable to electric VSS adapter, commonly from jagsthatrun or various other suppliers

While this is well and good, the VSS signals offered are either toyota, 2,000PPM, or 4,000PPM. Toyota signal is completely off, 2,000PPM works perfect for TBI ECMs but is pointless for Speedos etc. 4,000PPM is correct for SD TPI ECMs and 3rd gen speedos

My problem is that LS1 PCMs use a 40 pulse per revolution VSS input then change it to 4,00PPM output to the speedo, cruise abs, etc. JTR does not offer a 40 PPR or even mention the signal used. LS1 swappers sometimes just fudge the conversion ratio in their tune and reuse the 3rd gen VSS(most likely what Ill do). They do offer an external differential mounted 40 tooth reluctor ring for 9/10 bolts and can be read about in various threads here and on LS1 tech. I would go this route but Im using a Ford 8.8 rear which uses a different yoke so the ring wont fit and Im not planning on having a one-off CNC'd for this endeavor

This leads back to the output shaft issue. I have seen various comparisons of the different 700R4/4L60/4L60E output shafts and they pretty much interchange. The main difference is the VSS gear/reluctor. Older output shafts have the cable VSS worm gear clipped on very similar to the common 3rd gen VSS'. LS1 output shafts have a 40 tooth reluctor pressed on and from exhaustive reading the reluctor can be removed and pressed on an older output if the newer VSS is also retrofitted carefully

My main question is how do you get the output shaft out of the transmissions? Various sites and build threads say it can be removed with just dropping the tailshaft. The 3 rebuild threads I found show a C clip inside the tranny holding it in place so the tranny would have to be nearly completely disassembled to pull the output shaft. I could purchase the different parts new at a premium but for a project Im not sure will even work out, Id rather stick to JY stuff thats found for pennies on the dollar

jmd

iTrader: (4)

The output shaft R&R requires transmission disassembly.

Have you tried using a puller to remove the old gear and just tapping the new reluctor ring on? Some reluctor rings are fairly easy to tap onto the output. If the output shaft is drilled & tapped at the end, you can use all-thread, nuts and a sleeve to press it on.

Although I can't remember for sure if the reluctor and 4-bolt 4L60-E tailhousing are 100% bolt-on for the TH350 output shaft.

85MikeTPI

iTrader: (2)

The LS1 T56 uses the same 17tooth reluctor wheel as the LT1 T56, so I can't imagine the LS1 auto using a different VSS. What I've seen done is to have a thin reluctor wheel pressed onto the driveshaft yoke, then use a stock LS1 hall-effect pickup sensor bracketed close to the reluctor wheel. Should work in your application also.