th400 problem

[max1008]

The other day my ebrake stuck and when the drum heated it made my rear axle hop at about 45mph. I pulled over to fix the problem and when i put the truck in park it made a grinding sound. I checked the fluid, clear and didnt smell burnt. Put the truck in drive and nothing. Put in 4wd and nothing. I waited 10 min for everything to cool and the truck drove fine.

Last night I was coming down a hill to a redlight and it sounded like some bolts rolling forward in my trans. Light turned green and again nothing. Pushed to the side of the road and put in park and same grinding sound. I have no gears and the truck rolls in park.

Do you think the trans is the problem or maybe the converter? I feel that when the truck bounced due to the ebrake sticking that maybe something broke inside the trans or converter.

 

[Warthog]

Is your truck stock? Most CUCVs have a TH400 in them.

 

[patracy]

Rolling in park and the grinding in park indicates the parking prawl is broken or the teeth have been stripped. Coupled with the noises you've heard, I'm fairly certain you've got broken hard parts in the transmission. Since the 1008 (I assume we're talking about one with your screen name) has a detroit locker. If one wheel was locking up, the ratcheting shock load would be transferred back into the transmission and t-case.

 

[max1008]

Oh sorry, yes it is a th400.

Patracy- Yes it is a 1008. thank you that sounds about right. I guess I will pull the trans out tonight. Is there a way to check the trans when I pull it out to assure that its not the converter?
There isnt any grinding when it was driving and it rolls smooth.

 

[max1008]

and patracy can you change the subject line to th400?

 

[patracy]

Converter has no bearing over park at all. You'd have to pull the transmission anyhow if it's the converter. You can at least pull the pan to see if any hard parts are there.

 

[BigRix]

You could also have a problem with your transfer case and the ratcheting noise you hear is the normal sound of the parking pawl ratcheting against the gear. Perhaps the t case is in neutral or something inside is broken. If the output shaft of the trans is still rotating, it will make the same noise you describe.

 

[robert c neth]

judging from the grinding sound using park the internals are still turning.this means something is broke inside.could be the tranny or the t case ,i would do more research before ripping it apart.

 

[patracy]

Ahh I didn't read the part about you putting it in 4wd. Check the t-case first.

 

[tm america]

You probably have a transfer case issue or rear end problem.. most likely the fork pads on the range fork are bad allowing the sun gear to slide out of the plane

 

[robert c neth]

the grinding sound when you put it in park with the engine running means something is broke inside the tranny or tcase.with the truck in park jack up the rear wheels safely, and see if the drive shaft turns.if it does something is broke.you should be able to remove the pto cover and look inside the t case and see whats going on.if the all the gears turn in the t case when you turn the d shaft then its probably the tranny.there are other tests but i would be typing forever and am not good at it .good luck

 

[biggestc69]

He should have the NP 208 transfer case. No PTO cover on that model.

 

[max1008]

I pulled the pan and no metal and very little shavings on the magnet.

with the rear axle on a jack i turn the driveshaft and looking into a little hole in picture 2 i cannot see anything spinning in the trans.

With the truck in 4wd i spin the front driveshaft and the rear driveshaft and wheels spin but i cannot see anything spin in the trans through said hole.

I dont know if the stuff in the hole should be spinning or not.

Im stumped whether its the trans or tc.

 

[rickf]

The transmission is fine, what you are hearing is the parking pawl trying to engage while moving. Picture throwing the car in gear while rolling. You have lost something in the transfer case and it is allowing the transmission to keep turning as if it was rolling. The fact that it is intermittent I would also say the shift forks are suspect.

Rick

 

[tm america]

the reason you hear a noise when you put it in park is cuz the output shaft is still turning .The transfer case is the issue.. Not the trans..Put it in park see if you can push the truck .Then put it in 4x4 low see if you can push it?

 

[max1008]

sorry for being ignorant but the shift forks are in the transmission arent they?

 

[max1008]

truck does not roll in 4lo and park

 

[tm america]

there are no shift forks in the trans.There are two shift forks in the transfer case one for the range and one for mode..The one for the range slides a gear in and out of the planetary to give you high,low,or neutral.this is the one that is giving you an issue.You might have a broken snap ring on the output shaft of the transfer case that will let the gear train in the tranfer case move forward and backward and can cause that problem to

 

[tm america]

They make a updated -repair kit for the snap ring .. It is a three peice unit. the two halves go on and then a snap ring holds them on.. The rear main bearing has a radius on it that puts the pressure on the outside of the snap ring that causes it to fatigue and break.

 

[max1008]

thanks for your help everyone.

tm american- after draining the tc and putting back into 2wd everything worked fine again. I think your right on with the bend fork. I will get the tc rebuilt hopefully this weekend.