Transfer Case Slippage

[Blue2actual]

On the way home today, I had to hit the brakes rather hard in order to miss a car coming on the road (one way dirt road). As I was braking, I pulled off the road and let the car pass. I went to pull back on the road, and got no response from the drivetrain. I did check the dumb stuff first; i.e the selector was securely in 2wd and I was still in Drive. I put the truck in park (made a helluva grinding noise) and then proceeded to put it back in drive. I could feel the transmission shift through the gears ( I tried them all to eliminate the tranny from the mix). So I shut the truck off, and placed the truck in park. I fired it back up, and put the T-fer case into neutral, then back to 2wd, and proceeded to drive her on to the house. Now I know it's not normal for a T-fer case to just pop out of gear so to speak. Once I got home, I check the fluid level in the tranny and T-case and both levels were good and the fluid was not burnt or brown. I got out the trusty TM and looked at the trouble shooting and followed it. Found no issues. I wasnt able to check the linkage very well, so that's the only variable that I know of, that is left to check. Thanks in advance for the advice and feedback!

I did a search on here and found a similar post where a guy had his T-case pop out of gear after hitting the brakes rather hard. Someone suggested that it might be the nylon tabs on the fork getting worn out....?

 

[Westech]

Someone suggested that it might be the nylon tabs on the fork getting worn out

you got it

 

[JUNKYARDJOHN]

You don't say what vehical it is or what t/c. I'm asuming it's an oh9 with a np208. I have the same thing happening with my civi 82 long fleet 4x4. It has a np208 with over a 1/2 million miles. You are correct with the fork being worn. At least thats my problem. Any panic stop, or sometimes just being in o-d (it's a 700R4 tranny) & comming to an abrupt halt will cause my transfer case to shift into neutral. (forword inertia or gravity) You can't put the tranny back into park without first shutting off the motor, without grinding because everything is spinning. Your t/c shifter will still be in the 2-hi position although your t/c is actually in nuetral. Mine has done this about 2 dozen times in the last 5 years. If you shut it off... pull the t/c lever into 4-low (all the way back) , & back up into 2-hi, you will have moved your t/c shifting fork back where it's suposed to be, & should be able to start your truck, & drive off normally. I just attributed mine to old age & wear. SOMEDAY... I fully expect it not to keep working, but so far... so good. John

 

[Blue2actual]

You don't say what vehical it is or what t/c. I'm asuming it's an oh9 with a np208. I have the same thing happening with my civi 82 long fleet 4x4. It has a np208 with over a 1/2 million miles. You are correct with the fork being worn. At least thats my problem. Any panic stop, or sometimes just being in o-d (it's a 700R4 tranny) & comming to an abrupt halt will cause my transfer case to shift into neutral. (forword inertia or gravity) You can't put the tranny back into park without first shutting off the motor, without grinding because everything is spinning. Your t/c shifter will still be in the 2-hi position although your t/c is actually in nuetral. Mine has done this about 2 dozen times in the last 5 years. If you shut it off... pull the t/c lever into 4-low (all the way back) , & back up into 2-hi, you will have moved your t/c shifting fork back where it's suposed to be, & should be able to start your truck, & drive off normally. I just attributed mine to old age & wear. SOMEDAY... I fully expect it not to keep working, but so far... so good. John

John, I aint trying to be a prick, but I left out what kind of case it is on purpose. I made mention of it possibly being the nylon tabs on the fork wearing out, so that when one would respond, they SHOULD know that it is a 208, and MIGHT know something about that particular T-Case. The 205 doesnt have the the cheap a@@ nylon tabs. Just my opinion, but I'd like to get sound advice from you guys you know? The average joe mechanic may or may not know that a 208 has nylon and a 205 doesnt. I wanted to see if the responses I got would show that they knew what they were talking about if that makes sense? I did what you said, except that I just put the T-case in N and back into 2wd, then drove it home like nothing happened. These things are 25+ years old so I kind of expect stuff like this to happen. I appreciate the response thought! Glad to see it's not just mine T-case doing this. This is first time it has done it, but it's a relatively easy fix, until it finally wears itself out!

 

[gaunt1969]

May Just be the linkage. It can cause it if it is adjusted a little to short.
If it shifts real easy thru the settings the nylon tabs are prob good. The 208 tends to get a little stiff when they loose the tabs. But There is only one way to know for shure. "Crack the case"

 

[True Knight]

Im pretty sure that it is the shift fork. My 208 would slip out of gear sometimes, usually when bouncing around off road. I had the t-case rebuilt when I put in the 4L80E and the nylon tabs were completely gone and the shift fork itself was about halfway worn thru the thickness of the forks. The guy I had rebuild it said once the fork itself starts wearing it's not long before it'll break and then you will have no gear at all. The fork was $80 if I remember correctly.

 

[wikallen]

its the shift fork in the transfer case. You do not have to shut the truck off when this happens, just put the transmission in neutral, then move your transfer case to 4low, then back up to 2hi. If you are quick enough, you will not even hardly slow down and you will be back in gear again. But plan on fixing the transfer case, because it will happen again and more often.

 

[JUNKYARDJOHN]

John, I aint trying to be a prick, but I left out what kind of case it is on purpose. I made mention of it possibly being the nylon tabs on the fork wearing out, so that when one would respond, they SHOULD know that it is a 208, and MIGHT know something about that particular T-Case. The 205 doesnt have the the cheap a@@ nylon tabs. Just my opinion, but I'd like to get sound advice from you guys you know? The average joe mechanic may or may not know that a 208 has nylon and a 205 doesnt. I wanted to see if the responses I got would show that they knew what they were talking about if that makes sense? I did what you said, except that I just put the T-case in N and back into 2wd, then drove it home like nothing happened. These things are 25+ years old so I kind of expect stuff like this to happen. I appreciate the response thought! Glad to see it's not just mine T-case doing this. This is first time it has done it, but it's a relatively easy fix, until it finally wears itself out!

John ... I didn't take any offence at all to your post. I just don't like to assume anything, because I ussually wind up looking like a fool. I'm just happy to be able to respond in a helpful way with some real-world experiance that actually happened with me. I'm not much at giving out theories or ideas, unless someone specifically asks for them.(allthough alot of folks do) Every time it's happened to me, I picture that shifting fork being paper thin & am thankful when it goes back into gear..... someday it won't , but I only drive about 150 miles a month on average. (old retired bachalor living out in the mountains, & still playing with trucks) John

 

[coyote_hunter]

It's the shifting fork, once the plastic protector wears out it doesn't take long till the fork is worn through and you will be forced to drive home in 4-lo. It's not hard to replace the forks, but these cases are a dime a dozen, so you could probably just pick one up. If you do choose to get a new makes sure you get one that come from behind a sm465 or a turbo 400. The one that were behind the 350's and the 700's had different splines.

 

[Blue2actual]

Wow- I appreciate all of the replies! Glad to hear this this is a common problem on these things. When I go to rebuild it, should I just go with the 205 and call it a day? From what I have read, those are pretty indestructible being that it has gears and not a chain...?

 

[jdemaris]

. The 205 doesnt have the the cheap a@@ nylon tabs.

I wouldn't call the plastic tabs in 208s and 241s "cheap." Just a change in technology. All these cases have their pros and cons. 208 and 241 chain-drive units have a much nicer low-range then the all-gear-drive 205. The plastic tabs cut down a bit on high-speed vibration.

I ruined the 205 in my truck by an emergency stop. But, I was in 4WD low-range with the engine revved up and when I hit the brakes - it actually bent the mainshaft. I swapped in a 241 and have plowed snow for 10 years since.

205, 208 and 241 all last a long time if cared for. Now the 203 is a different story.

Check you linkage AT the transfercase. Either it fully engages, or it does not.

Pleny of 208s and 241s around for $50-$100. Just get the correct splines and speedo-gears. And note - contrary to what some say, you CAN use a speedo drive gear from a 208 in a 241 with some 1.5" ID bushings.

 

[coyote_hunter]

Wow- I appreciate all of the replies! Glad to hear this this is a common problem on these things. When I go to rebuild it, should I just go with the 205 and call it a day? From what I have read, those are pretty indestructible being that it has gears and not a chain...?

If you have a stock engine, you don't have enough horse power to tear up a 208. The 208 has it's advatages and disadvantages. If you keep fluid in them they will last. They also have a lower range than the 205's. If this is a daily driver that sometimes gets put in 4wd I would stick with the 208, since the 205 swap is not a direct replacement.

 

[JUNKYARDJOHN]

I have two of each right now, & have been using np205s since 1971. they both work really well. The 205s have a cast iron case & are gear driven & have the provision to hook up a P.T.O. transmission on them, where 208s are aluminum housed & chain driven. they both are good cases & have thier different attributes. The np205 indeed is a direct replacement in the M1031 or any other cucv with an automatic & a P.T.O. provision. John

 

[Cucvnut]

you can also look for a Np241C from a 89 suburban only its a 32 spine direct bolt in for the 208. it has a lower rang than a Np208. to swap a Np205 you need an adapter ,machine the 205 to fit the bigger bearing and then a new spline for the Np205. or try to find a Np205 that fits a TH400

 

[JUNKYARDJOHN]

My M1031 has a t-400 & a NP205. Those adapters (from t-400 to np205) are like gold. Super hard to locate & cost an arm & a leg when you do. John

 

[DokWatson]

I've had something similar happen, driving in 4 High and braked hard enough to lock the tires. The transfer case growled and popped out of gear. The only thing we could come up with was that with a worn shift linkage the drivetrain/body flexes so much it can 'half shift' the t-case.

 

[Wolf.Dose]

All above arguments are more or less correct to the individual use. However, there is one little thing, all of you did not take in consideration. The shifter forks run on a shaft, that moves them. The shafts are keept in position by a little ball made of steel. This ball is pressed into the grove of the shaft by a little spring. And when this spring looses tension, the shaft is not keept securely in place and under any circumstances and will not do its job any more correctly. So change the ball (might be not propperly round any more) and the spring.
This is a common problem on all manual shifted transmissions / transfers.
Wolf

 

[jdemaris]

I've had something similar happen, driving in 4 High and braked hard enough to lock the tires. The transfer case growled and popped out of gear. The only thing we could come up with was that with a worn shift linkage the drivetrain/body flexes so much it can 'half shift' the t-case.

I ruined a 205 transfercase from body-flex. That was in my 1968 Dodge Power Wagon. The body was so rusty it moved off the frame a bit if I braked too hard.

One day, while in low-range 4WD, I hit the brakes fast, but pushed the clutch in at the same time. But . . the body came off the frame so fast, it revved the engine way up AND engaged the clutch - as I stomped on the brake. This bent the output shaft in the 205 transfercase -and is proof it's not indestructable. That was 25 years ago, and I've been running a 208 in the truck ever since. Dodge uses a "divorced" transfercase, so spiine-counts aren't an issue for swaps.

I've got three plow trucks with 208s or 241s and never had a problem. Also got a HD diesel Dodge-Cummins with a 208. Much nicer low-range then the cast-iron 205, and they also shift easier.

 

[JUNKYARDJOHN]

I ruined a 205 transfercase from body-flex. That was in my 1968 Dodge Power Wagon. The body was so rusty it moved off the frame a bit if I braked too hard.

I guess I've just been lucky.... never had to drive one that rusty... I always felt some kind of responsabuility to all the innocent civillions that I shared the public roads with not to operate an unsafe vehical in thier vicinity.....never owned a dodge truck either though. John

 

[jdemaris]

I guess I've just been lucky.... never had to drive one that rusty... I always felt some kind of responsabuility to all the innocent civillions that I shared the public roads with not to operate an unsafe vehical in thier vicinity.....never owned a dodge truck either though. John

Saftey comes from the person maintaining and driving the vehicle, rust or no rust.

I'm 60 years old and haven't caused a single accident yet and drive many rusty "winter beaters" when the roads are salty.

I've been rear-ended and side-swiped several times by people in rust-free new cars - diriing like idiots. Normal humans drive often drive at their own percieved risk-levels. The safer a car feels - often the worse they drive.

And by the way, about my Dodge Powerwagon. Not long after my transfercase incident- a New York State trooper - driving a brand new rust-free cop-car at 80 MPH in a 50 MPH zone - crossed the center-lane, drove into me and my truck and tore the cab right off it with me in it. His new Trooper cruiser was totaled. So he - the "professiional driver" in a new car - was the one putting the public in danger - not me.

That Dodge Power Wagon is still used as a farm truck but after that trooper came close to killing me - I put a 1971 GMC cab on it. I've kept it all these years because I like the 4.88 ratio axle gears it has. Not something you find much anymore. Lousy on the highway but great in the woods. 4.88s with the transfercase in low-range is kind of amazing.