Transfer case quitting?

[Dogstalker]

So I was just digging my 1991 suburban v1500 out of a snow drift, I wasn't being hard on it at all, but I did have to rock it back and fourth a couple of times to get it to break through the drift. Now, when I got it out, it either seems like the transfer case in kicking out sometimes in reverse, and when it does sometimes I can hear a faint grinding/whining noise. It was having some trouble backing up, and I couldn't decide if my back tires were spinning or if the transmission was slipping or the tcase. It goes fine in all forward gears, grabs well, shifts well, 4wd works fine in drive, just iffy in reverse. Any idea what this might be? 1991 Chevrolet Suburban v1500 5.7 700r4 transmission. Thanks!

 

[1987 GMC Jimmy]

I'd check the fluid in the transfer case. While you're down there, I'd grab the front driveshaft and try to spin it to make sure that the universal joints are tight. Grinding and slipshod performance say check fluid first. You said 'either' in your original post, but you only said one thing. Are you just thinking it could be the t-case, or are you suspecting something else?

 

[Dogstalker]

I'd check the fluid in the transfer case. While you're down there, I'd grab the front driveshaft and try to spin it to make sure that the universal joints are tight. Grinding and slipshod performance say check fluid first. You said 'either' in your original post, but you only said one thing. Are you just thinking it could be the t-case, or are you suspecting something else?

Oh yea oops. I was thinking faster then I was typing. I was trying to say either the tcase or the reverse band in the transmission fried. But it's transmission I'm pretty sure, because I turned it off for a few hours and let it cool down and now it won't go into reverse at all.

 

[HotRodPC]

Yeah, 700r4's don't like to be rocked. The secondary valve body in the 87 and later models has an abuse valve in it. It's purpose is for rocking and being abusive to the transmission as you describe. It helps, but it's not fool proof.

 

[1987 GMC Jimmy]

Oh yea oops. I was thinking faster then I was typing. I was trying to say either the tcase or the reverse band in the transmission fried. But it's transmission I'm pretty sure, because I turned it off for a few hours and let it cool down and now it won't go into reverse at all.

Ahh, okay. As mentioned, it sounds like the that part of the transmission is toast, and it's all gonna need to be rebuilt.

 

[Rusty Nail]

Lol @ "abuse valve".

 

[HotRodPC]

Lol @ "abuse valve".

That is the actual name of it. Google it.