Allison has no gears at all - HELP!!

[chuntag95]

Just went to go to lunch and dropped the truck in gear, but got nothing. No feeling of it dropping into gear. No D, R, 1, 2 or 3. Tranny fluid is still in there, but it is acting like it is not pumping any fluid. HELP! :mad: :eek: :confused:

[sdaver]

nbsu switch or a fuse :confused: good luck

[chuntag95]

I tapped on the NBSU and that solved nothing. Didn' think about a fuse, but I did have a strange clunk this morning on the way in from 2nd to 1st when I was slowing for a red light. I wonder if something broke in that clunk?

[SoMnDMAX]

Is the shift linkage moving? There is a cable running from the shifter on the column to the drivers side of the tranny, where it hooks to the lever that passes thru the NSBU. These can break and or get disconnected, resulting in symptoms similar to what you describe.

May or may not be the problem, but it's worth a try.

[77TransAm]

If you feel the click, click in the shift lever as you move through the gears, then the shift cable isn't broken. There are no detents in the shifter or cable, only in the trans.

What lights up on the PRND2L in the dash? Is P highlighted when you're in Park, R in Reverse, etc? If you don't have anything lighted on the dash then the NSBU is a very likely culprit for your problem.

[Captain Mal]

Chuntag,

I can't offer any help but I was able to induce the same problem. In a frustrated effort to reproduce a group 1 shutdown with my injectors, I kept the transmission in 2nd gear and went up a hill holding 3,000rpm's. The truck did not shut down but after I stopped, the transmission did.

The selector showed all the gears but I had nothing. Maybe I got something too hot?

After a moment, and moving the selector around, it has resumed normal operation. I will not try that dumb thing again. You didn't do anything like that, did you?

[chuntag95]

Super Dave, I hope it is the NSBU switch. After I posted and went to wait on the wrecker, I noticed if I left it in gear long enough, it would flash the gear selector.
SoMnDmax, The tow truck driver thought about the linkage and checked it. All moved and was connected still.
Captain Mal, It had been sitting for about 3 hours doing nothing. The temp gauge on the transmission was reading under 140.

I tried putting it in and out of 4x4 with no results. It just flashed as if laughing at me. I hate that. :mad: They gave me a furd explorer to drive because there was only one diesel tech there yesterday. Oh Boy! :rolleyes:

I'll let you know what they tell me.

[BassinRVer]

Chris,

Sounds like you need to take a trip to Florida!!!!!!!!!!!!!

[RVGuy]

Chris,

Sorry to hear it man. Hope its just the switch and nothing more. Let us know.

[chuntag95]

I might need a trip to Fl, not for a new tranny, but to relax and detox after this is over. They called and told me the first thing was replace the NSBU switch but they didn't have one in stock so it would be this afternoon before they knew anything else. I really hope that's it so I can have my truck back for the weekend.

[DuramaxDicko]

Originally posted by chuntag95:
I might need a trip to Fl, not for a new tranny, but to relax and detox after this is over. They called and told me the first thing was replace the NSBU switch but they didn't have one in stock so it would be this afternoon before they knew anything else. I really hope that's it so I can have my truck back for the weekend. replaced my tranny at 647 miles and 3 weeks old with a rebuilt one... I got the message on the DIC "range shift inhibited" message

[chuntag95]

It turned out to be the NSBU switch. :D It is now tan vs. the old black one. They also replaced a battery that they replaced a couple of weeks ago. A cell was bad on it already. :rolleyes: I do have some good news, the replacement transmission cooler is working great. With it 98 - 102 on the drive home, the transmission temp was never above 170. :D Looks like a larger cooler might solve my 220 degree daily problem. Time will tell, but the first real test gave good results. :cool:

[sdaver]

good deal........have you ever checked out your tranny guage?

[chuntag95]

If you are asking have I had the tech II hooked up and verified the gauge and the sensor are the same, no. I have shot the pan with a laser temp gauge and found it to be lower than the gauge, but that is to be expected with the difference in position. I see a drop in "core" temp with the new cooler and that is what I was looking for. It cost me under $100 to change it since I got a used cooler off Ebay. Have only seen one more the size I have since I got mine and it was almost twice the price.

[Cliffee]

Isn't there a comment on Allison's Homepage about not changing the size of you cooler. They go on to say that the flow rate through the cooler cannot change the slightest bit?

[Silver Bullet]

Whew! :D I know that is a relief. Welcome to the other side...those with replaced NBSUs!!! :cool:

Consider yourself lucky...at least you didn't have to limp home 50 miles in 3rd gear!!! :mad:

[ColoradoSpringsToDaMAX]

Does anyone know if the NBSU has a TSB or anything out there for replacement to the new Tan unit before failure? I think dmaxallitech said something in another post about he would replace anyones under warranty that came and paid him visit, but it is a long way from Colorado Springs to Grand Rapids!! :D

[chuntag95]

Originally posted by Cliffee:
Isn't there a comment on Allison's Homepage about not changing the size of you cooler. They go on to say that the flow rate through the cooler cannot change the slightest bit? Don't know if that is on there site, but it was a concern for me. I think the intention was to not lower the flow any, which was definitly in my mind while deciding what parts to use. I got an oil cooler with huge fittings (AN -12 or 3/4"). The smallest size I have anywhere is the 5/8" hose barb on the new stuff. The factory lines are actually 5/8" OD, so I should be good. In case anyone cares, the OEM quick connects have 1/2" NPT male fittings. I used 1/2" NPT elbows and 1/2" NPT x 5/8" Hose barb to retain the use of them. This kept me from having to mess up the quick connect fittings or cut the lines. That way if I ever wanted to put the OEM back on, I could.

The cooler I got has actually less restriction than the OEM. I was surprised at how little the OEM actually holds and how slow it drained. The new cooler is 3x the size, with twice the thickness and the twice as many plates per inch than the OEM. It was designed for high volume oil in racing applications, but makes an excellent Super Heavy Duty Transmission Cooler. :D I still have not got above 170* and that was what I was looking for in this mod. I must also say, I copied it from another member, so I am the second one to do this that I know of. I don't think I will even put my fan back on unless I see it jump or something. I really feel like this will help my tranny live a longer life.