grinding

[Mmoore031908]

I have an 85 k10 305 700r4 np208. There is a grinding noise under moderate acceleration. If i drive like a grandpa it will shift great and won't grind at all. When its grinding it feels like its hesitating you press the gas amd it just wont go. Any one have any ideas?

 

[MadOgre]

Transfer case is full of ATF ?

 

[Mmoore031908]

Would that make it do that? How many quarts go in? I just drained the fluid and it had a good amount in it. I took the rear output shaft housing off and only had about half a cup of trans fluid come out and only a few drips from the drive shaft when it was pulled out. Im pretty sure it wasnt full. This is my first 4x4 so the transfer case is new to me. Ive read about the 700r4 sunshell cracking and grinding mainly i just want to rule that out. It grinds in 1st and 2nd when giving it a good amount of gas.

 

[marks86]

I would go under the truck and make sure all the bolts are tight. One time I had the same problem and it turned out to be all my transmission to engine bolts were loose or missing

 

[MadOgre]

Yep what Mark said!

The transfer case has two fill nuts/caps/plugs on the rear face of the transfer case. They are like 1 3/8" or something like that.

One on the bottom and one on the top about parallel with the driveshaft out put.

The bottom one is for draining. Once its drained reinstall the drain plug then remove the fill plug and fill with ATF DexronIII until it flows out of the fill plug opening then reinstall the fill plug and your done

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[Mmoore031908]

So just draining the fluid it looks as though I have a leak from the front output shaft. So im sure it wasn't full of fluid. Also there seem to be metal shavings in the T-case fluid once I drained it. How hard it is to put new seals in the input and output shafts and should I do that before fill it up to make sure that it doesn't leak ant more?

 

[MadOgre]

Its not that hard to replace the rear out put seal the front one can be little more difficult as the yoke and nut must be removed and reinstalled.

Depends how much its leaking?

A little bit of silver is normal especially if it hasn't been changed in a while. If its really really noticeable or you have large pieces that you can actually see them then it might be the issue. At any rate I would top it up and see if the noise is lessened or gone. Before going any further.

 

[Mmoore031908]

It seems to be just a drops. It doesnt look like it had chunks but the fluid looked like it had glitter in it. Do you know about what the capacity is? I drained all the fluid the other day that was in it. The fluid looked red like its supposed to it just sparkled. I have seen places that say 2.5 qts from a gm manual and some say fill to the bottom of the top plug(like my haynes manual) and from what ive read that takes about 5 qts.

 

[MadOgre]

Im not really sure to be honest I just fill it till it comes out the fill plug.

The little bit of glitter is fairly normal.

 

[Mmoore031908]

So I drained and filled it and it seems OK. No grinding or weird noises. I now have a weird issue with the tranny. If I shift it into drive(not overdrive) it will go to 3rd and I can't drive it even though that's how I have driven it for over a year. It has also kinda bucked going from 3rd to 2nd in drive.If I shift into overdrive the tranny shifts like its brand new. It doesn't buck at all going from 3rd to 2nd. It shifts smooth and drives great. Why would it shift great in over drive and not drive?

 

[MadOgre]

@HotRodPC

 

[HotRodPC]

So I drained and filled it and it seems OK. No grinding or weird noises. I now have a weird issue with the tranny. If I shift it into drive(not overdrive) it will go to 3rd and I can't drive it even though that's how I have driven it for over a year. It has also kinda bucked going from 3rd to 2nd in drive.If I shift into overdrive the tranny shifts like its brand new. It doesn't buck at all going from 3rd to 2nd. It shifts smooth and drives great. Why would it shift great in over drive and not drive?

The difference is how the fluid is routed in the valve body depending on which gear you selected changing the position of the manual valve within the transmission. For example, there is 2 ways to acquire 1st gear in auto tramsissions. There is 1st gear in D, and there is manually selected 1st gear. This part of how trans techs will use flow charts to diagnose transmission problems. So in D, you might get 1st with a band applied and the low reverse clutch pack applied. In 1st, it might be the low reverse clutch pack and an overrun clutch applied. So in a case like that, if you don't have 1st in either D or 1, then it's safe to assume the low reverse clutch pack is gone. If you have 1st in D, but not 1, then you can assume the the band is working fine, but the overrun clutch is not working and that's where the problem is. That's just for purpose of explanation though cuz I don't for certain without looking at a flow chart.