4x4 H gets skipped...

[Zaggnutt]

I would like to start by saying that I have scoured this site and FTE for this problem, but I have not found anything like it yet.

Difficult to explain, but when I attempt to shift into 4 High ( I have the manual shift lever) it just shifts past it... it doesn't set into 4 Hi if that makes sense. I have to just pull lightly out of 2wd while holding the lever and wiggle it back and forth slightly while looking for the dash light to come on. It doesn't actually engage the 4 Hi even if I get the light on, but that is another issue. Basically, it just doesn't settle into gear. The truck has a 4" lift and an auto to manual tranny swap (Previous owner). Just as an aside here, it does engage into 4 Lo normally.

Any experience with this?

 

[Boltgun]

Mine is like that, there is no real "notch" feel for 4H. Check the linkage bushings on the side of the case, mine are shot and I thinks that's causing my issues.

 

[Zaggnutt]

Are they the little grommets that hold the linkage pieces together? If so, one is new and one is good. I tore one apart when I took off the shift linkage housing and cleaned it... Thanks for the tip though. If you plan to replace the bushings, Advance Auto Parts has a little baggie with an assortment in it. I used that kit to replace mine... I think it was $6.00...Here's the link:
http://shop.advanceautoparts.com/we...=google&utm_campaign=gpla&utm_content=9110078

 

[jaluhn83]

I would go high and right on this and park the truck until you can take the t-case apart, or at the least carry a spare case and tools.

The reason I say this is I had a case fail on me about a year & half ago that started with similar symptom and turned into me getting stranded. In my case the first symptom was that it wouldn't shift into lo range at all - lever would move but it would just grind and not fully engage but was otherwise fine. At the time I thought it was a shift linkage issue. Subsequently about 3 months later with basically no warning it drops out of gear while cruising on I-5 in the middle of no where central valley CA 350 miles into a 500 mile trip with a trailer. Nothing quite as awesome as having the engine rpms go up and road speed go down at the same time.... Managed to limp it to an off ramp that actually had civilization (by more or less pushing as hard I could on the t-case shifter while trying to drive) but had to ask a friend to come get me and spend most of my 4 day weekend running around trying to find a replacement case and get it on.

Postmortem showed that the oil pump had spun and starved the gears - the reason it was jumping out of gear was the shift fork was so badly worn it wouldn't hold it in anymore, and the teeth on the pinion were pretty much shot as well. No way to fix it on the road short of replacing the case.

Now, I think your issue lies in the shift linkage rather than an oil issue like mine (there's a fairly complex linkage with several pins and bushings that changes the lever rotation into movement of the shift forks) but I'm very conservative with t-case issues now.

 

[Boltgun]

Postmortem showed that the oil pump had spun and starved the gears - the reason it was jumping out of gear was the shift fork was so badly worn it wouldn't hold it in anymore, and the teeth on the pinion were pretty much shot as well. No way to fix it on the road short of replacing the case.

From what I've seen before that's a pretty common problem with these cases.

 

[88beast]

its the linkage, mine needs held in just the right spot to be in 4h. but i wouldnt worry much, you can have a buddy on the brake in neutral and shift it manually from below to make sure it is the linkage if you want.

 

[Zaggnutt]

its the linkage, mine needs held in just the right spot to be in 4h. but i wouldnt worry much, you can have a buddy on the brake in neutral and shift it manually from below to make sure it is the linkage if you want.

The linkage seemed fine when I had it apart. What are the signs that it is the linkage, and what is the solution?

 

[Zaggnutt]

This is a work truck, so I need to be able to shift on the fly if necessary, but it will absolutely be hitting snow several times in the winter so I really want to nail this problem.

BTW, thanks for all your posts guys.

 

[79jasper]

You might have the wrong linkage.

There were at leat two different lengths I know of between the years for the 1356 tcase.

Sent from my USCC-C6721 using Tapatalk

 

[LCAM-01XA]

The linkage seemed fine when I had it apart. What are the signs that it is the linkage, and what is the solution?

The linkage is stupid-simple on these things, just your standard Z-bar setup. The flat bar has a plastic bushings on each end, see if you can easily pop the bar off the shifter and transfer case levers - you're not actually removing it tho, just testing if it looks like it's gonna be annoyingly hard to make it let go on either end - loose bushings pretty much let go at the lightest touch, tight ones sometimes result in bent levers

That said, what happens when you pull the shifter from 2H straight back into 4H, without pushing down on it - do you hit the shifter gate between 4H and N, or can you slide it all the way into 4L? The gate is there to prevent you from overshooting 4H during a shift-on-the-fly while truck is in motion, the idea is to pull straight back on the stick till it hits the gate and that's your 4H. The shifter linkage is non-adjustable, meaning with the shifter against the gate and linkage bushings in decent shape the lever on the side of the transfer case will be in its 4H position - now whether the shift fork inside the case will also be where it needs to be is a different matter, you could very well be dealing with the same mess Jaluhn83 experienced.

Boltgun, all of the above applies to you as well - your shifter is different in that it has a longer throw and to clear the gate between 4H and N you have to pull the stick to the left before pulling it back (as opposed to Zaggnutt having to push down on his before pulling back), but the idea is the same - from 2H you pull straight back and once you hit the gate you're in 4H, to continue from there on additional motion is needed with the shifter.

 

[Zaggnutt]

That said, what happens when you pull the shifter from 2H straight back into 4H, without pushing down on it - do you hit the shifter gate between 4H and N, or can you slide it all the way into 4L? The gate is there to prevent you from overshooting 4H during a shift-on-the-fly while truck is in motion, the idea is to pull straight back on the stick till it hits the gate and that's your 4H. The shifter linkage is non-adjustable, meaning with the shifter against the gate and linkage bushings in decent shape the lever on the side of the transfer case will be in its 4H position - now whether the shift fork inside the case will also be where it needs to be is a different matter, you could very well be dealing with the same mess Jaluhn83 experienced.

Ahhh, okay. I thought I posted about the bushings... I think that was on my "Ebay buyer beware" thread. Anyway, I've already had the shift linkage body and linkage off to clean/lube the body. Replaced a torn bushing in the process that I destroyed in the removal process.

Okay, so I understand what is supposed to happen, but not why it is happening... When I pull the shifter back, the light blinks on and off immediately like 2wd and 4hi are right beside each other. The shifter then travels back to the gate and normal motion stops before pushing down to engage 4lo. Does that make sense? My next question is why is this happening? Could it be from the tranny swap the PO did? Follow up question: How do I fix it?

 

[LCAM-01XA]

Ahhh, okay. I thought I posted about the bushings... I think that was on my "Ebay buyer beware" thread. Anyway, I've already had the shift linkage body and linkage off to clean/lube the body. Replaced a torn bushing in the process that I destroyed in the removal process.

Okay, so I understand what is supposed to happen, but not why it is happening... When I pull the shifter back, the light blinks on and off immediately like 2wd and 4hi are right beside each other. The shifter then travels back to the gate and normal motion stops before pushing down to engage 4lo. Does that make sense? My next question is why is this happening? Could it be from the tranny swap the PO did? Follow up question: How do I fix it?

You did mention the bushings, I was only explaining them as a general PSA and also for Boltgun to know what to look for since he mentioned suspecting them as the culprit for hi issues.

So your transfer case is in 2H when shifter is in 2H position, and you get 4L when shifter clears the gate and drops into the 4L position, right? And when your transfer case is in 4L the shifter cannot be moved without first pushing down on it, correct? This tells me the shifter mechanism and linkage are operating properly - 2H and 4L and on the opposite ends of the shifter travel, if linkage was off even a bit you would get one but not the other. So in theory if you got the shifter's end positions working properly the two in the middle (4H and N) should also be there where they need to be. But since you can't get 4H while all else appears to be good, that makes me suspect the transfer case itself, my suggestion would be to pull it from truck and open it and see what's going on inside it.

As a side note, the "4x4" and "low range" lights on the dash are operated by a pair of ball switches, much like what a manual transmission uses to engage the reverse lights. They are not the most reliable thing out there, if they are gummed up they can stick and make the indicator light come on when they shouldn't - I often have the "4x4" light stay on for a while after using the 4 wheel drive and shifting back into 2wd, I know for a fact the transfer case is in 2H mode since I can turn the front shaft by hand, just the switch is getting wonky and needs replacement or at least good cleaning. So don't put too much faith in the "4x4" indicator light, instead shift into what should be 4H and then crawl under the truck and first visually verify the shifter has indeed hit its gate (you're already under the truck so might as well, right?) and then grab the driveshafts by and see if either of them will turn freely - do this with engine off obviously but also with the front hubs NOT locked in, if the hubs are locked then front shaft won't turn by hand even in 2H mode and will seem like transfer case is in 4x4 mode while in fact it is not.

 

[Zaggnutt]

Thanks LCAM, I'll get on that ASAP. I'm going to tell you right now, I will exhaust every other option before pulling the transfer case. I do not have a shop or garage to work and I live in an apt. I have nowhere to keep anything clean, neat or out of the elements. I will pay closer attention to whats happening when I'm underneath and see what I can learn and report.

 

[Zaggnutt]

Won't be able to get anything done til probably the weekend, but I may be able to go out tomorrow night and play with it a little to get some info...

 

[LCAM-01XA]

Just an idea, if you do narrow it down to the transfer case itself, you may wanna look into swapping a NP/NVG 271 case out of a 1999-2003 Superduty truck - thing is a monster, even tho it's made of aluminum it's almost as heavy as the cast iron NP 205, rated at about 40% more torque capacity too (NP 205 is a bit over 5500 lb-ft, NP/NVG 271 is almost 7900 lb-ft). Note that you will need the driveshaft yokes from the donor truck as the transfer case itself uses companion flange outputs (big circular flange that you bolt different yokes to depending on what you need), and altering driveshafts will be required. If my truck didn't have cable-drive speedometer I'd have already done that swap, you guys with the electronic speedometers have it so easy sometimes

Swapping a transfer case is easy enough. Splitting one for repairs makes quite the mess even if the fluid inside was drained.