Lq4 and 4l80e

[dcameron787]

Looking for some help on this. I did an lq4 swap in my k20 last winter. I kept the original th400 tranny and 208 transfercase. Truck works great with the exception of it has hard time finding idle and throws the check engine light when I’m coming to a stop as it does not have a vss. It does not stall or effect anything but bugs me.I have the Dakota didgital in-line vss but it really does not do anything. I consulted my tuner(frost) and he said there’s is nothing on the market that works including the gps vss by Dakota. So thinking I’m just going to take the plunge and swap in the 4l80e. My question is how can I get a 4wd 4l80e with both vss installed. Is this possible? I looked everywhere for a 241c 32 spline passenger side drop transfer case with the vss but it’s impossible to find. From what I have read if I use a vss behind the transfer case I can only use 4wd hi and 4low will work but won’t come out of first gear. I’m actually ok with this as I don’t really use low at all. If anyone has done this swap please let me know what your setup is. Thanks again. Always great advice on this site...

 

[yevgenievich]

Either retrofit 208 with vss, live without low range working correctly using 4l80e sensors or build a frequency divider box that would divide the vss frequency when low range is selected while using 4l80e.
Or another possible option to look in to is tow/haul mode. Might be possible to program shift points for 4l80e that would more or less line up when low range is used by connecting low range to tow/haul mode.

 

[dcameron787]

Thanks for the reply, I’m ok with not having 4low. What’s involved in retrofitting the 208 to add a vss? Also, can I get the rear vss installed on a 4wd 4l80e?

 

[yevgenievich]

there are adapters that would work without changing anything. A reluctor ring can be installed on a 208 with minor machining for the sensor to mount. 4l80e by itself has two sensors, one input and one output.

https://jagsthatrun.com/collections/speed-sensors

I have a 4l80e/241c combo as stock in my burb and have not done a retrofit of vss my self, but there have been couple of threads started here from people that have done it.

 

[climb-101]

you can add the second reluctor ring into the 4l80. I did it on mine, you just add the ring/sensor from a 2wd setup. what transfer case you using?

 

[dcameron787]

Thanks, thinking I’m going to keep the 208 and just add the speed sensor to the 4l80e from a 2wd. What happens when you try and use 4 low with this set up?Will it just stay in first gear? I’m fine with that as I do t use it much.

 

[yevgenievich]

4wd 4l80e on my suburban already has the output sensor. Did not realize that normally they do not. It will likely stay in 1st

 

[dcameron787]

Also, were you guys able to use the original shift linkage for the tranny and transfer case?

 

[yevgenievich]

Also, were you guys able to use the original shift linkage for the tranny and transfer case?

There are stops in the column for a 3 speed unless broken/wore. Otherwise I believe linkage is the same. Options are either swap some parts from a 4 speed column or adjust to only go down to second instead of first gear.

 

[dcameron787]

Thanks for all the great info. Before I proceed with the 4l80 has any one done a 6l80 on a lq4. Not finding much out there..

 

[Doppleganger]

How did you fare on this? I'm looking at a similar swap into an 85 4wd. THX

 

[deviatedsheep]

take the Check engine Bulb out. or add a Late Model Manual controlled TC to your truck with has the VSS.