Hi I'm new here. I have a '99 ZR2 Blazer, manual 4x4. I was driving when out of no where, i had no gears, it wouldn't drive anymore. So I had it towed home, did some internet research and didn't find much on this specific issue. With the truck started I can cycle through my gears(even without the clutch engaged) and there is nothing happening. It did briefly work after I disconnected my battery, but now that doesn't help.....Any ideas?

 

You state manual 4x4 and you mention the clutch, but just to be clear you have a manual transmission in your truck, correct?

If so, disconnecting the battery shouldn't have any impact on power transmission between the engine and a manual transmission. There are really only two components that handle that if it is in shifting into gear inside the trasnmission, the clutch and the input shaft of the transmission.

If not and you have an automatic transmission, then there could be a number of things wrong.

Please verify and we'll see if we can't get you pointed in the right direction.

 

Yes a manual, it is not automatic. Weird why it worked again for a couple days, then no gears again. I would think if it was the input shaft...it wouldn't work again once it was broke. Also the clutch works fine, lots of hard resistance, springs back. I had mentioned that I can cycle the gears easily without using the clutch(truck running),, and nothing happens, this would also indicate to me its not the clutch. With the truck not running, I can also put it into any gear, or where the gears would be, and push it like it was in neutral.

 

It is possible that something broke in the shift linkage and you aren't actually moving anything inside the transmission when moving the shift lever. This would essentially leave the transmission in neutral. Do you hear any change when pressing down on the clutch pedal vs up (best if done with the vehicle on jack stands and a helper working the clutch so you can listen at the transmission for signs of the input shaft speeding up or slowing down)?

 

Okay, I don't really hear any change, it sounds the same whether I use the clutch or not. Also when I shift into a gear, its like nothing is there....no resistance what so even, I'm going down to pick it up right now (left it at work last night) i will jack it up when I get it home and check the linkage....thank you for your input

 

You'll need to pull the shift lever boot (and possibly the center console if equipped) and then the four bolts that hold the lever to the transmission extension housing to get a look at the inner workings of the shift linkage. The Getrag HM290 (NV1500/NV3500) is an internal rail configuration.

Attached is a picture of the top of your transmission as you would see it out of the vehicle.

 

UPDATE: K, so I went to get my truck, I decided to do a couple things (I had read about them regarding 4x4 issues I was having previous...service 4x4 light was on, no lights on the selector buttons and clicking at the TCCM) so I unhooked my battery, touched the cables together, unplugged the TCCM and left it all for 10 min. I hooked everything back up and now its its 4 low, but all gears work again. Service light is still on and the 4wheel selector llights are still out...but I limped it home in 4low........so weird.

 

T-case shifting into neutral will definitely do it as well, but you didn't mention any problems with the t-case in the OP, but that would be why disconnecting the battery helped.

3 or 4 button 4wd switch?

 

I was thinking the tcase and trans issues were unrelated till now, sorry. It's a 4 button switch, 2hi, 4hi, 4lo, and the auto button next to those buttons. May be a TCCM issue I'm thinking. Thanks for all your input.

 

I would start by looking at the wiring connectors on the TCCM (located behind the passenger kick panel below the dash in front of the door. You are looking for signs of corrosion on any of the pins. This area was a poor choice for the TCCM as the 4wd switch uses varying resistor values in the contacts to alter a voltage signal on a single pair of wires.

If you find the connection to be clean and free of corrosion, I would then test the switch resistance from the connector at the TCCM. You can find the appropriate values listed in THIS THREAD from the Tech Article (DIY) section.