DSRE388
Registered Member
Good hopefully its a simple deal
CK5
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Allison 1000 5spd in limp mode
- Thread starter SpeedlabDan
- Start date
Problem solved! At least my problem, I tested all wires in the harness to the tcm for continuity. Looking over the schematic after installing the new nsbu (didn't fix it) I noticed on the 7 pin connector that I was previously told was outgoing only, a ground as well as a ignition power. I quickly whipped up a couple leads to the harness and before I started I noticed I already had a shift indicator! Good sign, so cleared the tcm codes and fired. A trip around the block proved I had all gears! Also no trouble light or codes! The programmer was picking up that the tcm was requesting illumination but it was not lit. Upshift and downshift appeared normal. I'm sure the more it's driven the Allison will get used to the 6 38.5s it's pushing! Thanks for the help guys!
sounds just like my problem i posted up . . . stand alone harness makes forgot my brake signal / obd1 plug . . .
Yes this power source and ground were definitely part of the original harness that would have saved a few days of head scratching
call them up and complain and tell them your sending them the bill for shop diagnostic / code reading / new switch that didnt fix it all cause they screwed up . i almost think mine was from them also over 15 years ago screwed up .
Howell?
have to go digging . might have been street and performance ? ? ? 15 years ago man . and if i even wrote it on the ecm .
i did love the program in it tho . street driving she was nice . but once you matted it hard she was firm and hard untill you turned the key off .
i did love the program in it tho . street driving she was nice . but once you matted it hard she was firm and hard untill you turned the key off .
They've been helpful where they can. I will call to let them know for future builds. I wouldn't want anyone to pull their hair out like I have haha
Good news! 
So the saga continues. Upon installing the triple stick and permanent wiring of the nsbu 7-2 pin plug, and installing new trans lines (old were sweaty) the trans now kicks out of gear abruptly. This happens in any gear. Shift to the next gear in any direction and it goes right back in to gear. It kicks out soon as the accelerator is pressed. There is also no tcm code. No illumination.
What I've tried:
Put the old nsbu switch back on. Adjust. No
Wire the nsbu direct to the battery like the original test where I had all 5 gears for a ride around town. Nope
Checked the plugs on the trans, pass through connector and vss. All seem good
Checked the red and Grey connector at the tcm. Appears fine and ground pin has ground.
Of course retracing my steps. I also feel it must still have something to do with the nsbu wiring. All unused wires in the 7 pin (5) were separately insulated and then shrunk in a larger harness to look clean.
It was getting late, tomorrow IL going to try hard wiring the 7 pin to the battery like the test to see if it works again
Fml
What I've tried:
Put the old nsbu switch back on. Adjust. No
Wire the nsbu direct to the battery like the original test where I had all 5 gears for a ride around town. Nope
Checked the plugs on the trans, pass through connector and vss. All seem good
Checked the red and Grey connector at the tcm. Appears fine and ground pin has ground.
Of course retracing my steps. I also feel it must still have something to do with the nsbu wiring. All unused wires in the 7 pin (5) were separately insulated and then shrunk in a larger harness to look clean.
It was getting late, tomorrow IL going to try hard wiring the 7 pin to the battery like the test to see if it works again
Fml
Update:
Retracing my steps, I finalized wiring for the +/- on the 7 pin of the nsbu. Double checked alignment of the selector shaft.
Pulled the vss back out of the output housing. Checked the tone wheel for play. All good. Looking at the pickup on the vss it appeared it could be contacting the tone wheel from the mangled o-ring on the threads that was also starting to weep fluid from distortion. Replaced the oring with a slightly thicker part with a smaller diameter to keep it from walking out. Keep in mind this speedo housing is re-machined to fit the aftermarket vss. The housing doesn't have anough thread to counter sink the surface for the o-ring for a better fit so when I tightened it I was very careful to just snug down on the o-ring enough to seal adequately without plunging the pickup too far towards the tone wheel.
Fired up and brought to temp, checked fluid an put it in gear. All good. Took it around the block and shifted through to third a few times. Confident that it'll shift to 4-5 for now.
At this point I did shift to 2wd low. This did not go as well. The Allison did not like shifting to 2nd with this differential in vss speed to trans rpm. It wouldn't shift to 3rd and seemed to derate rpm at 3k.
There is a detent plug for the factory 263 tcase that I'm not using that I was assuming was just for illumination but I suppose it could work in conjunction with some of the 4wd signals to the nsbu 7pin. I'll have to dig through the factory schematic for sure. For now I'm glad to be able to drive the truck.
Retracing my steps, I finalized wiring for the +/- on the 7 pin of the nsbu. Double checked alignment of the selector shaft.
Pulled the vss back out of the output housing. Checked the tone wheel for play. All good. Looking at the pickup on the vss it appeared it could be contacting the tone wheel from the mangled o-ring on the threads that was also starting to weep fluid from distortion. Replaced the oring with a slightly thicker part with a smaller diameter to keep it from walking out. Keep in mind this speedo housing is re-machined to fit the aftermarket vss. The housing doesn't have anough thread to counter sink the surface for the o-ring for a better fit so when I tightened it I was very careful to just snug down on the o-ring enough to seal adequately without plunging the pickup too far towards the tone wheel.
Fired up and brought to temp, checked fluid an put it in gear. All good. Took it around the block and shifted through to third a few times. Confident that it'll shift to 4-5 for now.
At this point I did shift to 2wd low. This did not go as well. The Allison did not like shifting to 2nd with this differential in vss speed to trans rpm. It wouldn't shift to 3rd and seemed to derate rpm at 3k.
There is a detent plug for the factory 263 tcase that I'm not using that I was assuming was just for illumination but I suppose it could work in conjunction with some of the 4wd signals to the nsbu 7pin. I'll have to dig through the factory schematic for sure. For now I'm glad to be able to drive the truck.
lots of electronic shifting trans use the 4low signal to let it change to a separate set of shift tables and line pressures from what i understand . but if you cant change the value of the ratio then this also might toss you for a loop on the 205 ratio and the magnum box as they might be different from the 263 box .
This is exactly what I suspected, but I don't see how I couldnt wire an override switch on the triple stick but then again there are two low ranges now so it may never totally work perfectly.
thats why i think running my 4l80-e as a 2wd might help me . but the quick4 controler can be setup with up to 3 different ratios for low so i am covered ether way i think .
Yea, I'm learning as I go here as I don't know anyone who has done this particular combo/swap successfully yet. It does kinda work but it's not right
