JayTheCPA
Well-Known Member
Looking to start a thread on exactly what it will take to mate a ZF S6-650 to the 6.5; in my case this is a swap out for the 4L80E and rounding out the discussion to cover swapping out other transmissions is a good thing. Am seeing where there is some interest in the ZF-6, but the search feature is not working well with query items like “ZF-6”, “ZF S6-650”, etc so it is a little tough to get a feel (or results) where anybody has completely worked through a ZF-6 conversion.
Am nearly convinced that the 4L80E is not the right tranny for me given my preference on speed control is with the throttle / gearing and then friction when necessary. I do have an ECM tune which gets better TCC lock-up above 45 mph (versus the OEM tune) which I like, but brake application forces an unlock which I do not like. Resulting from a good bit of research and conversations on the topic of getting the 4L80E to act more stick-like, it looks like this is a square-peg and round-hole goal where the OBDII programmers have yet to conquer this yet and likely it is simply outside of what the 4L80E will do anyway. Another research area was addition of a BD Torqloc to get the lower gears to lock-up at lower speeds, and while this tool looks nice, it seems to have a mild temperamental aspect of throwing a code in OBDII systems or making the tranny go into limp mode if not handled correctly.
Enough of the background and on to the topic . . .
Am seriously thinking about the GM variant ZF S6-650 as it is pretty much what I want:
- A standard shift.
- Plenty beefy to tow and a proven platform.
- Lower engine RPM’s (and noise) on the highway.
For swapping to a ZF S6-650, here is what I have so far:
- The ZF S6-650 was converted into an Avalanche 5.3 gasser with a really good write-up, so I know this is close to a drop-in solution but it does need some fabrication / parts replacements.
- Bolts up to the 6.5 (and, from what I am seeing, most if not all of the GM V8 engines).
- Heavier than the 4LXX and NV platforms by about 60#’s.
- Costs more than the NV.
- Need to shorten the rear drive shaft and get a longer front shaft (latter not necessary for 2WD).
- Need to install all the clutch pedal guts and cut a hole for the stick.
- Might need a lift kit or modifications to the body (depending on the suspension).
- (Self evident, but listing anyway) An ECM tune when replacing an automatic.
- (Self evident, but listing anyway) A towing clutch (Luk, South Bend, etc).
Only pieces that I have not dug into yet are:
- Verifying that the misc transfer cases bolt-up to the ZF-6 (looks like they do) and (for the push-button 4x4 systems) whether a wire harness extension is necessary due the ZF-6 pushing the x-fer back a few inches; also need to verify whether the input shaft mates with the ZF-6 or need to change the shaft.
- Making it work with the push-button 4x4 system so that the system knows when the transmission is in neutral (confident this is workable otherwise the push button system would not work with a NV).
- Whether it needs a different flywheel (and if it does, definitely a single mass and NOT the dual mass).
- If a different flywheel is necessary, does it need a different starter?
- Whether my 8600# suspension will need a lift or hump expansion; or put another way, which bodies / suspensions need modification.
- Whether the speedometer needs recalibration and if so, is it changeable by software or ship it off for another ECM tune.
Here is what I am trying to avoid:
- Moving this thread out of the 6.5 section as the focus is how the ZF S6-650 mates to the 6.5 versus a general transmission discussion (not to mention am not seeing a ZF-6 Forum (yet)).
- Comparing the ZF S6-650 to other transmissions: focus is how to make the swap work and nail down / work through any ‘gotchas’ that I have not already caught.
Am nearly convinced that the 4L80E is not the right tranny for me given my preference on speed control is with the throttle / gearing and then friction when necessary. I do have an ECM tune which gets better TCC lock-up above 45 mph (versus the OEM tune) which I like, but brake application forces an unlock which I do not like. Resulting from a good bit of research and conversations on the topic of getting the 4L80E to act more stick-like, it looks like this is a square-peg and round-hole goal where the OBDII programmers have yet to conquer this yet and likely it is simply outside of what the 4L80E will do anyway. Another research area was addition of a BD Torqloc to get the lower gears to lock-up at lower speeds, and while this tool looks nice, it seems to have a mild temperamental aspect of throwing a code in OBDII systems or making the tranny go into limp mode if not handled correctly.
Enough of the background and on to the topic . . .
Am seriously thinking about the GM variant ZF S6-650 as it is pretty much what I want:
- A standard shift.
- Plenty beefy to tow and a proven platform.
- Lower engine RPM’s (and noise) on the highway.
For swapping to a ZF S6-650, here is what I have so far:
- The ZF S6-650 was converted into an Avalanche 5.3 gasser with a really good write-up, so I know this is close to a drop-in solution but it does need some fabrication / parts replacements.
- Bolts up to the 6.5 (and, from what I am seeing, most if not all of the GM V8 engines).
- Heavier than the 4LXX and NV platforms by about 60#’s.
- Costs more than the NV.
- Need to shorten the rear drive shaft and get a longer front shaft (latter not necessary for 2WD).
- Need to install all the clutch pedal guts and cut a hole for the stick.
- Might need a lift kit or modifications to the body (depending on the suspension).
- (Self evident, but listing anyway) An ECM tune when replacing an automatic.
- (Self evident, but listing anyway) A towing clutch (Luk, South Bend, etc).
Only pieces that I have not dug into yet are:
- Verifying that the misc transfer cases bolt-up to the ZF-6 (looks like they do) and (for the push-button 4x4 systems) whether a wire harness extension is necessary due the ZF-6 pushing the x-fer back a few inches; also need to verify whether the input shaft mates with the ZF-6 or need to change the shaft.
- Making it work with the push-button 4x4 system so that the system knows when the transmission is in neutral (confident this is workable otherwise the push button system would not work with a NV).
- Whether it needs a different flywheel (and if it does, definitely a single mass and NOT the dual mass).
- If a different flywheel is necessary, does it need a different starter?
- Whether my 8600# suspension will need a lift or hump expansion; or put another way, which bodies / suspensions need modification.
- Whether the speedometer needs recalibration and if so, is it changeable by software or ship it off for another ECM tune.
Here is what I am trying to avoid:
- Moving this thread out of the 6.5 section as the focus is how the ZF S6-650 mates to the 6.5 versus a general transmission discussion (not to mention am not seeing a ZF-6 Forum (yet)).
- Comparing the ZF S6-650 to other transmissions: focus is how to make the swap work and nail down / work through any ‘gotchas’ that I have not already caught.
)