[Guest]

I'm confused, what's new, and hoping something bad isn't on the way. It started about a month ago and has happened two times since. My garage is in an unpaved narrow ally, and I was having to use 4 wheel drive to get in and out because of the snow drifts. I had my Blazer in 4 wheel drive and was gunning it a little. I have a automatic Th350. I would stop put it in reverse press the gas to get moving, stop the truck put it in forward and press the gas. I was doing this a few times, but after about three times, I went to put it into drive and nothing, it wouldn't engage

. I would go through all the gears, reverse and all the drive gears and nothing. I went to put it in park, and there was the zzzzzzzzzzzzzz grinding noise. I turning the truck off put it in park, turned it back on and it then ingaged the all the gears. Yesterday I'm driving home coming down a hill. My dog was sitting next to me, and she slipped on the seat and bumped my trasfercase (I have a NP203 that has been changed so I have manual locking hubs). While I'm driving, my truck goes out of gear. I pull to the side of the road, turn it off then started it, but this time the truck wouldn't engage like it had done previously when this happened. I turned it off, put it in park, started it but it still wouldn't engage. I did this a few times and nothing. I'm not sure I know why I did this but, I put the transmission in neutral, moved the transfercase shifter to 4 high down to 4 low a few times. I then put the transfercase in neutral turned off my truck so I could put it in part (it wouldn't let me put it in park, it would make the zzzzzzzzzzz grinding noise.) Started it and it now engages into reverse and all the forward gears. Is my transmission going out, my clutch, or is there something wrong with my transfercase???????? I hope there is a guru out there because I don't know if I should keep driving it. It shifts fine through second and third gears.

 

[578]

its in your y-case. i am not a driveline expert, but i know enough to...damnit you have an auto dont you? could be in the TC i think. but i drive manuals so I'll tell you what i know about them. i have replaced the whole driveline once and the T-case 3 times. when the t-case is going out it will either outright break on you (loud angry sounds of breaking) or more likely, the shift forks wear out a bit and it can pop in and out of gear. i suspect your shift fork is worn or bent, or perhaps just out of adjustment. you can adjust some but i have no intimate knowledge of the 203 t-case. my 241 would pop out of gear and into N when i would accelerate from a stop. so i had to hold it in gear while letting out the clutch. turned out to be a worn shift fork that wasnt keeping everything lined up properly

 

[RRich]

Grab a strong flashlight, a small mirror and go under it. If you are lucky the T-Case's shifter's at fault. Inspect the bolt through the shifter lever - pivot - and the pin from the lever to the shift rod. Sounds like it's loose or worn and not letting it go into gear all the way.
May be helpful to have someone shift it while you watch underneath.

By your description, it's not a tranny problem.

 

[Guest]

Thanks. How would you explain how I was driving in 2 wheel drive last night, the transfercase shifter gets bumped and then I can't get the transmission into gear? That's what I don't understand.

 

[578]

if shift fork isnt adjusted right, or shift linkage is binding, it does all sorts of crazy thigns with shifting. not going into gear can most deafinately be attributed to this. it might be something else, but it certainly CAN be this

 

[882]

I would check the shifter linkage to the t-case. When I had a TH350/NP205 in my truck, the tranny would make the same zzzzzzzzz sound when being shifted into park while the t-case was in neutral. Sounds to me like your t-case is bumping out of gear (into neutral).

 

[3187]

i did not see what year etc your blazer was, but something similar happened to my 1999 gmc sierra. as i pulled up to park in a parallel spot put truck in reverse.....NOTHIN but parking paul sound. pulled ahead no prob. back into reverse same thing.....put in park to ck under truck NO PARK. drove it home next day pulled trans case, to ready to pull trans, checked output shaftof trans had park, went to trans case 1 way it held other way it did not. BINGO, tore it apart and the shift fork somehow was out of sync i guess i would call it. its operated by electronic solenoid. put it all back together havent had another prob with it.

 

[Guest]

okay. I obviously don't know much about the t-case. I thought that while the t-case was in nuteral it has nothing to do with the transmission. When I put it in 4 high or 4 low is when the t-case engages into the transmission. Am I wrong? That is why I don't understand when I'm driving in 2 wheel drive, and the transfercase shifter gets bumped, why would that knock out the transmission from gear. Any good books or web sites you know that would explain how the t-case and transmission interact?

Thanks for the help!

 

[578]

transfer case has basically 4 settings. 2WD, N, 4X4, and 4LO

thats for most of them, some are autotrac, and some have full time 4X4. but basically the trasfer case is a bi chain that loops around the "driveshaft" and transfers power to the front driveshaft. this is a very simplified explaination of it. in 2WD the chain is not powerd so no engine power iswasted turning the front drivesahft and tires. in neutral, the chain freewheeels, and in 4X4 the chain is powered. no this isnt exactly accurate, and some t-cases are gear driven instead of chain, but it kinda gives you the jist of it