Slip, grinding. Transmission or transfer case?

I need help figuring out which part is broken.
Symtoms:
Cant exceed 20 mph in any gear 1-2,3,D,R in any t-case position.
Slips out of gear and grinds untill i let off gas. pops back into gear when i slow down.
T-case shifter dose not move or pop out of gear.
Transmission shifer dose not move or pop out of gear.
This all started after i made a hard accleration.

I took apart the t-case to install a sye, then recently took it apart again to apply a new gasket(old one leaked, i suck at gasket maker). This is why im considering the t-case as a problem, this maybe a coincidence though.
I just tore it apart again after the problem happend, did not find any damage.

Suggestions or any stories of similar problems are wanted.


(shifting linkage to t-case is in good condition and so are the mounts)

Aw4, Np 242 transfercase, 4.0

I checked the tranny fluid and it had no metal fragments. it just looks dirty.

Could the torque converter be dammaged? Can the shifting linkage mess up internaly in the transmission? (External shifting linkage to the transmission is ok)

Found the problem part. It is comming from the transfercase. This part is the shifter sleave. It is connected to the shift fork and inserts into the first planetary gearset. It has been ground down pretty good. i pulled a junkyard 242 apart and looked at the same part. the teeth were alot more square than mine.



Item number 12


Now is this normal wear? or is the a shifter linkage the problem? and more importantly dose anyone know where to get another one for less than 93$

Just had an idea. Checked the np 231 diagram. Looks like it has the same part, which expands my options alot. Now hopfully i can go back to the junkyard and find a 23 spline 231 and take the whole planetary gearset and shift sleeve. I will try this next weekend.

Made it the junk yard. The imput gear and low range planetary gearset are the same, so you can swap them around. The Shift sleeve, the part that i need and is worn down, is not interchangable. you will need to grab one from your type of transfercase. (242 or 231)

I ended up doing just that. First i grabed a 242 imput gear, low range, and shift sleeve. But i found out that the imput gear spline count was wrong. Mine is 23 spline The 89 i grabed the part from was a 21 spline. So this weekend i went back and grabed another imput gear and low range gear out of a 92 np231.

(In 1991 (the same year the 4.0 HO was introduced) the AW4 splines increased to 23.)

Assembled transfercase with the 1992 np231 imput gear and low range gear. Then used the 1989 np242 shift sleeve. slaped it back together, and as i was bolting it to the jeep i noticed that the shifter connection on the transfercase itself had alot of play. I put a shim between the transfercase housing and shifter linkage. It no longer wiggles.

My conclusion:
This transfercase is just worn out. I still cannot put a finger on what exatly caused the shifter sleeve to slip out of the input gear.

Things that could have caused it are: worn plastic inserts on the low range shift fork, loose shifting linkage in the transfercase, shifting linkage not adjusted right, worn bushings in the rear bearing retainer that hold the shift rail.

The transfercase is not slipping anymore, im calling it a temporary fix. The 242 is a great transfercase, i dont care what the numbers say, it is just as strong as the 231. but i cant stand the way they designed the internal shifting linkage. The 231 is alittle bit more simplifyed, but still sucks. And both cases have a very small teeth on the imput gear and shift sleeve. All the power transfers through teeth that are only 3/8" wide! i dont like!
sorry my rant is over. :viking: