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The mythical CUCV 4L80E swap

icer97

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NE MO
I found the GM part number for the lube orifice cup plug. For the solid plug for the 4x4 housing without the orifice you want GM part number 9427692. For the guys wanting to convert the other way and convert a 4x4 transmission into a 2wd and wanting the orifice hole in their plug for the 2wd version they want part number 8675516. I found the 4x4 plug part number by entering it into ebays search and got one coming for $11 shipped.
 

brazengoat06

Member
362
2
16
Location
Tulsa, OK
I found the GM part number for the lube orifice cup plug. For the solid plug for the 4x4 housing without the orifice you want GM part number 9427692. For the guys wanting to convert the other way and convert a 4x4 transmission into a 2wd and wanting the orifice hole in their plug for the 2wd version they want part number 8675516. I found the 4x4 plug part number by entering it into ebays search and got one coming for $11 shipped.

Awesome info for the thread thanks! I ended up using a 0.530 freeze plug from Oreillys for 58 cents. I also retained it with retaining compound into the case. Again having not looked up what kind of pressure is one the other side of the plug (shouldn't be very much) this should work good. Again thanks for the part numbers so we could complete our 4x4 conversion info. I don't think any other forum has all of this info.
 

icer97

New member
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NE MO
No problem Ive done a lot of searching and digging to the point my head is spinning. I originally was just going to size up a freeze plug to install for under a $1 and like you I cant imagine there being much pressure on the lube side back there so id think a freeze plug would be just fine. I just went ahead and ordered the GM plug since it was only around $10.
 

brazengoat06

Member
362
2
16
Location
Tulsa, OK
Looking through the pictures I'm not seeing the exact mods made to the shifter linkage. I've gotten my 4l80 bolted up and getting the controller in tomorrow. Now just gotta tie up all the loose ends.
 

True Knight

Active member
673
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43
Location
San Pedro, CA
Looking through the pictures I'm not seeing the exact mods made to the shifter linkage. I've gotten my 4l80 bolted up and getting the controller in tomorrow. Now just gotta tie up all the loose ends.
For the shifter linkage the only real modification was lengthening the linkage rod. I took round bar of the same diameter as the original and welded in a few extra inches. Then you just have to play with the adjustment and position of the linkage to get it to have full range of shifting. It's not to hard to get it to work properly.
 

richingalveston

Well-known member
1,715
120
63
Location
galveston/Texas
on my install I had to lengthen the rod and move the mounting hole in the frame. I made and add on bracket that bolted to the original hole and moved the hole toward the back of the truck about an inch to 1.5 inches. It still took a lot of working with to get the linkage to work with all the gears.
I do not have pics on this computer but I have posted the pics before so they are on this website somewhere.
 

brazengoat06

Member
362
2
16
Location
Tulsa, OK
Thanks for the info. I tried to welding two of the small brackets together that the shifter rod goes through on the transmission, it works on some gears but won't return to park. Looks like the rod still needs a little bit of length added.
 

Kaiserjeeps

Active member
459
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28
Location
North Idaho in the woods
What controller are you guys using? I have been on the phone with a couple of them and am still undecided. I have been reading a TON of info on this on the web. Gaaah my head is spinning. I am waiting for the GM oiler plug to show up and the transmission goes to the rebuilder. I have the fully splined shaft cut down to swap in also.
I am using the NW fabworks adapter for my fig 8 NP205 mount. It is 9/16ths thick and keeps the tall fig 8 adapter unmodified. The fully splined shaft is cut with this adapter in mind. Early 2x 4L80E's have the rear speed output. Most 4x4 versions don't have it and it is in the transfer case. The NP205 needs to be modified for this speed sensor or you can do what others have mentioned earlier in this thread. My trans is a 93 and needs the few ATRA technical service bulletin updates.

I also discovered lots of wear in my slip yoke 205. The input gear has bad spline wear. Original New Process input gears are not available and only Asian ones are made. I am also converting the rear slip yoke to a fixed yoke with a kit from Offroad designs. http://www.offroaddesign.com/catalog/transfercaseparts.htm
The fixed yoke NP205 in my truck now is a version that is not as desired as others. It is a front output synchronized version. It is currently making noise when I turn a corner and or brake. It sounds like splines bumping. I read it was used for the early 80's and did not fly. It was for auto hubs and you cannot get the bushings for them. Non syncro'd front outputs use bearings and can be rebuilt. This straight non syncro front output is the desired NP205 to use.

To tell the difference... The Syncro version, look at the big round AL cover on the back. It will be fully cast and you CANNOT see the back of the steel bearing that supports the front output shaft. It is just a raised round casting. The cover all one solid piece.

The desired and better version, looking at the same cover, you will see a machined hole through the cover center and the steel bearing back will be visible. Most likely lightly rusted and definitely looks pressed in. I believe all CUCV's came with the desired version except they also have the slip yoke feature which can be converted easily to a fixed yoke.


The poster with all the output shafts shows one to use for the NP205. It says 9 1/4 long. This will not work. At least with the fig 8 adapter. You want the fully splined 8 + inch shaft that offers unlimited choices on trimming and makes sure you have full spline engagement with the transfer case input no matter what you choose to do. That's what I bought and with the 9/16ths thick NWfab adapter, my fully splined shaft OAL (***UPDATED***) is 6 3/4 sitting on the bench up to the end of the shaft. OR with the NWfab adapter on the trans, the shaft should stick out to 4 1/4 +/- a 1/16th from the adapter to end of shaft. This length will allow full contact with the NP205 input gear collar with about an 1/16th of trans splines sticking past the rearward edge of the splines in the 205 input collar. (***END OF UPDATE*** There is a shallow dead space past the splined 205 collar. Subtract 9/16 more off the OAL of the fully splined trans shaft if you machine the adapter and go that route. The NW fabworks adapter was 149.00 Easy for me as the closest machine shop is nearly 2 hours away.

The later short (in height) NP205 adapter has the feet cast forward and hits the 4L80E bottom cover. Avoid this short mount. It cannot be used unless there is a spacer between the trans case and the adapter. I will triple check all this and post any updates or corrections. I will post some pics also.

I am leaning towards the BEC Quick 1 trans controller. US shift. http://www.usshift.com/usq1.shtml

And these guys, 4l80E simple shift. A brand new product. I am cautious of new stuff. This is compushift.
http://www.transmissioncenter.org/compushift_4l60e_4l80e.htm

I have read that TCI is a relabled US shift that has been detuned some. Some of the info I found was a couple years old. It's the internet right. ;)

Good thread....
 
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richingalveston

Well-known member
1,715
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Location
galveston/Texas
stay away from tci. it is crap. went through three before giving up and buing US shift1 controller. very good unit. comes with wiring harness. you do need tach interface which you can get from DS1 module from Dakota digital.

the Dakota digital and us shift controller together cost less than TCI.

I wasted a year dealing with tci and had to have tranny rebuilt a second time.

just my 2cents
 

brazengoat06

Member
362
2
16
Location
Tulsa, OK
Too late for me on the TCI info lol.

Question for the OP, how much did you have to lengthen/shorten your drive shafts? It looks like 2.5 inchs, does that sound right? I'm taking mine in to be reworked in the am. Thanks
 

True Knight

Active member
673
179
43
Location
San Pedro, CA
I haven't had any trouble with the TCI unit. It seems like quite a stretch but maybe the three Richingalveston had were all bad from the same lot or there was some other unknown issue causing the problem. Who knows, but mine has worked flawlessly.

By the way, are you going to try that speed sensor that you posted the amazon link to? I originally wanted to try that with one from a 6.5 but I had read that the signal output wasn't correct and/or wasn't strong enough for it to work properly. And you can't post anything on the internet that isn't true right? Ha ha. If it does work I would probably buy the part and use that for the RPM signal instead. Makes for a much cleaner install.

As for the drive shafts, 2" seems about right. I can't remember exactly how much they needed to be adjusted. I just provided the measurements that the drive shaft shop asked for and they built the proper length shafts.
 

Kaiserjeeps

Active member
459
7
28
Location
North Idaho in the woods
It seems all of the manufactures have had problems. Summit has some reviews on the TCI. Not many to find elsewhere.

I learned something today. The US shift unit requires the trans (94 up) to have a black Holley GM #8684216 pressure control solenoid to function properly. Earlier transmissions such as my 93 have a Bosch (silver) pressure control solenoid and needs to be changed to Holley. This info is from the installation instructions on BEC's website.

I like the apparent simplicity of TCI. But I need to check on some more stuff with the other manufacturers.

I am getting 2K quotes to rebuild my 4l80E.. I am almost stunned.
 

Kaiserjeeps

Active member
459
7
28
Location
North Idaho in the woods
I just got off the phone with Kevin at US shift or Baumann Electronic Controls (BEC). I specifically asked about the Tach signal for the Quick 1 controller. He said it was NOT needed for the unit to control the transmission.
The Quick 1 controller has been on the market for 6 years now. so it is not a new intro that "should" work. The quick 4 controller has way more bells and whistles and can use the tach or engine RPM signal although not required to control the 4l80E. The quick 1 has power and ground, key on connection, front VSS or turbine speed, rear output speed, and main trans controller PRNOD321 which handles line pressures and converter lock up etc.. The quick 1 is plug and play with laptop tuning only if you want to change some very specific things. The quick 1 also has a feature that by adding a ground switch to a specific wire, it enables a second tuning program such as a towing program. The quick 4 has 4 different programs available. The tach or engine RPM is a nice to have though. Kevin said that I could tap into my ISSPRO tach crank based signal if I wanted to. Only on the quick 4. The quick1 would suit my needs just fine. However I don't like the idea of needing a laptop at all. I need to go shovel some snow and think on this some more. I like the simplicity of TCI. I like the additional tune ability of the US shift.
And as for the post I read on another forum regarding TCI being a detuned US Shift. Kevin at BEC said they have never ever been associated with TCI and no products have ever been bought or sold to them. Gotta love the internet.
 
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brazengoat06

Member
362
2
16
Location
Tulsa, OK
so i got my tci unit in this morning and got it all hooked up and guess what, it doesnt work. so what do i do, i call the tci tech assist phone number. but all i get is some guy with an attitude and no assistance. I was told to send the unit back to whom i bought it from and thats all. well guess what you guys still built the **** thing so what difference does it make! end rant...

Dont buy TCI!!!
 
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