transfer case locked in 4x4....sorta??

[ponytail]

i believe i have the np2o3 transfer case and here is whats going on. in 4wd low all works well. in 2wd low i get nothing(like neutral) neutral is right. 2wd high i get nothing( like neutral). 4wd high works fine too. i assume this is the shift forks? also when i put truck in gear i get a nice clank. all u joint are good so i assume its coming from loose chain in transfer case? should i pull/rebuilt it or replace with something better? the 205 maybe?

[OrrieG]

Before you dig into the transmission take a look at the shifter. When the 203 factory shifters get worn the handle moves but the levers do not. I got so tired of crawling up under mine to get it back in place with a big screwdriver I got a spare and made a twin stick.

The clunck is probably the chain taking up slack when you put it in gear. If it it really stretched it will jump gears in 4 loc with a noticable clunk and stutter in forward progress when it is really loaded. You can pull the lower front cover and bearing retainer, take care it has a bunch of needle bearings to look at it. If the chain is sloppy you will see it. I rebuilt my 203 with a Doug Nash part time shaft kid in 85 and newer chain and gear and haven't had any problems with it off road. The part time kit goes a long way toward keeping the chain from stretching because it takes the load off of it during normal driving. I kept it this build because I did not want to have to refabricate everything a third time (its in a 59 frame).

If you don't mind rounding up all the pieces a 205 would be the way to go but it is not a direct bolt in replacement for the 203. Around here they are on CL all the time, usually with a 4 speed trans still attached.

[ponytail]

swapping both may be my way to go really. it has a 3 speed auto now and i think i would like having overdrive. this truck is a work horse but anything 60mph+ feals like i am killing the motor. (high rpms). truck is in great condition so it rarely goes off road

[cabcorner]

Do you have lockout hubs on your truck .My truck does the same thing when my hubs are unlocked. The internal differential on the 203 puts all the power to the axel with the least resistance. With the hubs unlocked it wont move in the High or Low positions.I don't think there is anything wrong with your transfer case. Removing a drive shaft will also cause this. The High lock and Low lock positions lock the internal differential in the 203 sending equal power to both the front and rear axels.

[csb#356]

Agree with the above post. Sounds like someone put manual hubs on it and no part time kit. But if theres not manual hubs I agree with Orrie G.

[ponytail]

Originally Posted by cabcorner

Do you have lockout hubs on your truck .My truck does the same thing when my hubs are unlocked. The internal differential on the 203 puts all the power to the axel with the least resistance. With the hubs unlocked it wont move in the High or Low positions.I don't think there is anything wrong with your transfer case. Removing a drive shaft will also cause this. The High lock and Low lock positions lock the internal differential in the 203 sending equal power to both the front and rear axels.

truck does have warn manual hubs. but when i shift to 2wd low or high i get nothing at all. just like neutral. im not sure how hubs would make a difference. its not getting power to either driveshaft

[csb#356]

Theres is a differential inside the transfer case so when you don't have it in lock (which locks the differential) then it works like an open differential sending the power to the path of least resistance (that being the front axle with the hubs unlocked). I bet if you put the truck in gear and got underneath it the front driveshaft would be spinning. Or just lock the hubs in and run it in 4hi (not 4hi lock) and see if the truck moves. I would be willing to bet thats whats going on. Its stumped many before.

[cabcorner]

The 203 transfer case was was used in full time 4x4's and did not have a 2 wheel drive shift position. The shift pattern on a 203 from the seat to the dash was High lock,High,nuetral,Low,Low lock.Full time 4x4's did not come with lockout hubs. Like CSB said I'd be surprised if it didn't move in high with the hubs locked.

[ponytail]

ok. i was under the assumption there was 2wd option on the shifter. AWD says it all really. so the front drive shaft and axle will be spinning either way. so, what about the whole clanking problem. assuming loose transfer case chain? is there an adjustment or is it stretched? sounds just like a bad u joint but they are all very tight and sound seams to be coming straight out of t-case. also this may be same problem....when truck is accelerating it pulls smooth but when i let off gas it gains a good vibration. 4wd shifter shakes like crazy. hit gas and goes right away. this could be a sloppy chain as well? my first thought was out of balance drive shaft.......

[OrrieG]

The vibration could be the chain. Under acceleration it is tight, let off the gas and the chain gear and shaft are loose and "fighting" the main shaft through the internal spider gears. I could see how that would cause a vibration. You can check the chain by pulling cover #51 in the diagram below. Be careful when you remove it, there are a bunch of needle bearings that support the chain gear shaft. If I remember right I think you can partially pull it and see the chain. If it has an obvious sag or you can move it up and down easily with a screw driver it needs replaced. Your decision then becomes to fix it and put in a part time kit or go with another model of case. FWIW I rebuilt and converted mine to part time using a shaft kit in 1985 and used the truck as my DD, camping and hunting rig until 2000, putting about 8K miles on it every year. This build I looked at the chain it is still relatively tight.

[cabcorner]

My guess would be that the front drive shaft is causing the vibration.It could be the CV joint ,but i had one where the slip joint got a lot play in it and would vibrate at certain speeds. The clank is probably a combination of chain slack and all of the play in the drivetrain.I would agree pull the cover on the back of the case to see how loose the chain is. Use grease to hold the needle bearings in place for reassembly and remember to refill the case with 10w40 . Gear oil or tranny fluid will damage a 203.I have a parts 203 that the chain is so loose it contacts the chain case. The part time shaft kit that Orrie G refers to is no longer available new . Remember for normal driving you should lock in your hubs and run in the high position. Unlocking the hubs and driving in High lock all the time will eventually damage the internal coupling . I love my 203 but it does get complicated.

[ponytail]

its not the front drive shaft as i took it out a couple weaks back.

first of all.... can i replace chain while in truck? i am assuming not. so if i cant get the part time kit then what? is there no way to free up front drive shaft and diff? just seams like a lot of wear on parts that dont need to be moving. not to mention gas milage or power loss in pushing the extra parts as inute as it may be.

[ponytail]

oh yeah...i appreciate the diagram. man there is alot of parts there!

[cabcorner]

Mile marker i believe still offers a part time kit for the 203 but its a wedge kit that replaces the spider gears not the good shaft kit. Super winch made a kit that replaced the spiders with a crown gear,I don't know if its still available. You could install the part time kit with the case in the truck but doubt you could replace the chain without removing it.If you are looking for gas milage now may be the time to invest in a 700R4 -208 combo, Before you invest $300 into a 203. My 86 has a 305-700R4-208 with 3.08 gears and is decent on gas ,around 14MPG. Another option is to look for another 203 as people tend to give them away(around here $50-75)

[OrrieG]

You need to tear the case apart to replace the chain because the main shaft has to be pulled. Mile Marker does list the shaft kit model# 95-92203. Others that have installed it say it is identical to the original Doug Nash DNE2 unit from the 80's. The patent has been through several companies, apparantly MM is the current holder.