4WD not engaging- Grinding gears

[camdensc]

I am experiencing a problem engaging my 4WD. After changing the tranny filter, changing the tranny and transfer case fluid, and replacing the vacuum lines, the gears pop out of 4WD and grind similar to a manual tranny when the clutch is not engaged.

Doing a search of past threads, it looks like worn shift forks may be the problem. Is there any additional troubleshooting I can do to confirm that it is the shift forks?

Will I do any damage driving in 2WD until I can fix the problem?

Thank you in advance for your help.

 

[K45]

Is it when you are going in 4 whel hi or low, or both? Does it do anything when try shifting into neutrel? i know in 4wheel low you need to be stoped and best put the tranny in neutrel then shift into low then shift the tranny into drive. 4w hi should not be a problem but best try to shift at low speeds. I hope that helps out. Also while the engine is completely off and tranny in park move the tcase shifter through the different setting does it hift smooth?

 

[camdensc]

I was stopped when I engaged 4WD hi, then it popped out at about 15-20 mph. I then stopped and put it into neutral, when I heard the grinding. I tried putting it into low, which seemed to work, but again grinding going back to neutral when stopped, and heavy grinding going back into 4WD hi while stopped. I did not do alot of changing gears, because of the grinding, and I will go check to see if I can shift through the gears with the engine off. Thanks

 

[camdensc]

With the engine off I can shift through the gears, but I would not consider it smooth. It tends to need an extra push between 2WD and 4WD hi. Between 2WD-N-4WD low, it is a bit smoother.

 

[KenzMan]

Everything was working fine before you done fluid/filters and lines ?

 

[camdensc]

I just took delivery from Fort Jackson, here in South Carolina. I am still trying to work the bugs out.

 

[dependable]

Like k45 said, be sure you are in neutral on transmission when you shift transfer case and not in motion. Also disengage hubs. Try runnig though gear positions with engine off. Transfer case lever should be jogged to the right between 2wd & 4. Check operators manual This transfer case can get caught out of gear, especially if you are used to manual transmission. If you still have a problem, it may be a linkage adjustment. If it is fresh from military, it is unlikly( but not impossible) for it to have worn out forks. good luck.

 

[camdensc]

I will try some of your suggestions in the morning, thank you.

 

[K45]

sorry for the late response. I was wanting you to check these simple things to help eliminate some factors. With the engine off sometine it can be a little snugg or tough to go from 2wd to 4wd low. With these blazer from the military having low milies I will lean towards it not being wore out but more of an adjustement. Sounds like it is not fully engaging which can cause the grinding andpoping out of gear if it was never fully engaged. You should be fine driving 2wd make sure you disengage your hubs. It might not hurt to pull the Tcase open it to make sure the gears are not messed up. Hope that helps

 

[hobie237]

Like k45 said, be sure you are in neutral on transmission when you shift transfer case and not in motion. Also disengage hubs. Try runnig though gear positions with engine off. Transfer case lever should be jogged to the right between 2wd & 4. Check operators manual This transfer case can get caught out of gear, especially if you are used to manual transmission. If you still have a problem, it may be a linkage adjustment. If it is fresh from military, it is unlikly( but not impossible) for it to have worn out forks. good luck.

Huh? 2-4H should require nothing more than a pull of the lever, you should be able to shift in and out on the fly, hubs locked or unlocked. Shifting into N or 4L on the transfer case requires the "jog to the right," not the shift from 2 to 4H. The shift to 4L should be done with the truck stopped and in neutral, but nothing else is required- you don't have to shut it off, unlock the hubs, or anything else.

Sometimes the gears and whatnot don't line up quite right, when they don't, it's best just to bump it into D, move forward a bit to get everything realigned, and the try again.

I fail to see what the "tests" you suggest with the engine off, hubs unlocked, etc. would tell anyone. Whether or not the hubs are unlocked is pretty irrelevant in terms of whether the transfer case is working, same with the engine on/off.



I'd just crawl underneath the truck and see what's going on while somebody else works the transfer case lever. You could also work the transfer case from the underside, just to see what's going on. I'd figure there's an issue with alignment and/or adjustment down there, although I've not messed around with these transfer cases enough to be more specific. Could be the fluid, I guess, what did you use? Mine came out with the transfer case shifter BROKEN OFF by some numbskull in the Army, so consider yourself lucky.

 

[K45]

the test is just to check for biinding with no interference from the rest of the drive train. As far as the hubs, it is just a reminder when running in 2wd drive to have them disengaged it has no bearing on the Tcase and the problem with shifting. Let us know what you find out.

 

[fstfrdy]

there is adjustment with the shift linkage that is most likley the problem my brother on occasion has a similar problem with his and the linkage is the culprit. if the transfer case comes out of gear dont just try to shove it back in you must have the tranny in neutral and then you should be able to re-engage the transfer case. dont try to go from drive to park with the engine running and the t-case in neutral you can destroy the front pump on the tranny.shut down engine and reengae everything and start over.just my . i do not own a cucv but have owned and worked on there civi counterparts

 

[camdensc]

Thanks to everyone for the suggestions, I have been away from the house all day with my kids, and am just getting back in now. I hope to try out some/all of the advise tomorrow. Thank you again, I will let you know what I find.

 

[camdensc]

I know I said I would check on things tomorrow, but I had to go out and make a test drive. This is what I found tonight. I drove a couple hundred yards in 2WD with hubs disengaged. Then I engaged the hubs and shifted into 4WD high- Everything good so far. I stopped and shifted back into 2WD- still good. Next I shifted into 4WD high from 2WD on the fly, and back to 2WD on the fly- everything still working good! Next I put the tranny in neutral and shifted into 4WD low- worked fine.

The problem that I finally ran into was shifting out of 4WD low. I stopped the truck, put the tranny in neutral, and shifted out of 4WD low into neutral, then grinding of gears when I tried shifting out of neutral on the transfer case. I shut the truck off, put it in park, and fired it up, then was able to shift the transfer case into 2WD and 4WD high without a problem.

I tried the same sequence into 4WD low one more time, and had the same results.

I guess the good news is that I can shift into 4WD high and back into 2WD without a problem, and I probably will not realistically use the 4WD low very often, so it wont be that big of a problem, but I would like to figure out a fix.

 

[hobie237]

Next time you're having trouble shifting out of 4L, try putting it in drive, dribbling forward a couple feet, stop, shift back to neutral, and try to shift out again. Every once in a while I've had mine not want to come out of 4L, but bumping into drive to realign stuff always has managed to work. I don't see what shutting off and restarting the engine would do, aside from shaking things around a bit and realigning them, maybe.

 

[camdensc]

I am not sure about shutting off the engine either, but it was suggested by another member, and it worked for me. Turning the engine off did allow me to shift out of neutral, and up into 2WD, since the gears were no longer turning in the transfer case. Getting out of 4WD low isn't the problem I was experiencing, it is the gears grinding when I attempt to shift the transfer case out of neutral. I will try to put the tranny in drive for a couple feet to see if that works as well, thank you.

 

[1stDeuce]

Ok, scamdensc, your transfer case is FINE. It's just that shifting it through N should be done SWIFTLY, with no pause. When you pause with the t-case in N, the output on the trans starts spinning (yes, even though trans is in N, it will spin the output...) and hence when you try to re-engage Hi or Low range, you'll get grinding. It's perfectly normal.

If you find that you end up with the t-case in N, key the engine off and shift to wherever you want to go, but shifting swiftly THROUGH N with the transmission in N and the engine running will be fine. Actually, you can most easily accompleish this shift while just barely still rolling, such that the dog teeth are slightly turning, and they can mesh correctly.

If you are having problems with it jumping out of 4wd hi, it's likely a shift fork issue. If you have problems jumping out of 4wd LOW, it's likely just that the linkage needs adjusted.

To check adjustment, you're looking to "feel" the detent in the T-case that's 4HI. It should roughly position the lever right against the rear stop built into the floorpan. (that would be where the shifter must be moved to get to N.) If it's off, particularly if it need to be past the stop to feel like it's detented in 4HI, you need to crawl underneath and adjust the linkage untill it's OK.

Best wishes!
Chris

 

[K45]

Ok, scamdensc, your transfer case is FINE. It's just that shifting it through N should be done SWIFTLY, with no pause. When you pause with the t-case in N, the output on the trans starts spinning (yes, even though trans is in N, it will spin the output...) and hence when you try to re-engage Hi or Low range, you'll get grinding. It's perfectly normal.

If you find that you end up with the t-case in N, key the engine off and shift to wherever you want to go, but shifting swiftly THROUGH N with the transmission in N and the engine running will be fine. Actually, you can most easily accompleish this shift while just barely still rolling, such that the dog teeth are slightly turning, and they can mesh correctly.

If you are having problems with it jumping out of 4wd hi, it's likely a shift fork issue. If you have problems jumping out of 4wd LOW, it's likely just that the linkage needs adjusted.

To check adjustment, you're looking to "feel" the detent in the T-case that's 4HI. It should roughly position the lever right against the rear stop built into the floorpan. (that would be where the shifter must be moved to get to N.) If it's off, particularly if it need to be past the stop to feel like it's detented in 4HI, you need to crawl underneath and adjust the linkage untill it's OK.

Best wishes!
Chris

Exactly right. And I agree your tcase if it was able to all the shifting in out no problem. I think the issue of it poping out of 4wd is that it may not have been fully engaged. Sounds like you ar on the right track. Just enjoy it and play with the different mods and if it still becomes a problem you have enough peeps here to help out

 

[camdensc]

Thanks guys. I may have been babying the transfer case a bit, not wanting to shift through neutral too fast, but it sounds like that is what may be causing my problem. Thank you again for the help, if moving through neutral faster doesn't help, and I have a hard time with the adjustment, I will ask for some more help.

Being new to these vehicles, I don't have alot to contribute to the forum yet, but I did make a donation yesterday to help out until I have some knowledge to add.

Thanks again, great site!

 

[KenzMan]

I'm not too sure about damaging the pump in the transmission if both tranny and transfer are in neutral and you shift to park , but as 1stDeuce said , with both in neutral your tranny output is spinning and when you shift to park it will start ratcheting the park lock and can come to a banging stop when/if it does engage which could cause damge to the park lock . It's a nasty yucky sound you don't want to hear , and I do agree that if you can't shift the transfer while both are in neutral to shut it down .

I am also new here and agree fully this is an awesome site , it's a great resource for anyone with any type of MV . Already helped me out and for that I throw a big THANK YOU to site and members !!!