t-case + Drivetrain concerns and help needed - The 1947 - Present Chevrolet & GMC Truck Message Board Network

clapage6 · 11-04-2013, 01:14 PM

Hi all, I have a good mechanical background however haven't owned anything bigger than my toyota pickup until a few months back when i got my 83 Crew cab drw for hauling desert toys etc around. Also never did much drivetrain work even though...always been a motor-head while someone else jimmied with suspension/gearing etc...

concerns/advice/pointers needed:

1. Good sized clunk when going into reverse. I've been seeing around could be U-joints/diff etc. Does anyone know of a decent way of diagnosing the exact cause a "SAFE" way?

2. I can hear the tcase gears spinning though the t-case shifter in the cab at all times... gets a little annoying; not crazy loud but i can def. hear it even with my window down .... is this how all np205's are or is there something else wrong? everything seems tight as far as linkage is concerned? Is there a decent thread anywhere with pics on drain/fill/sight plugs on the 205?

I think that's it for now

Thanks guys

Rubble · 11-04-2013, 03:20 PM

You can check the u joints by seeing if there is any movement right at the joint.Grab the driveshaft & try to wiggle it back & forth,if there is any movement your joints need replaced. Also look at the caps & see if they are shiny,that means the needle bearings are getting bad& need replaced.If you run down the road a bit,stop & feel the u joints to see which one is hot or warm.You probably know this already,but when your checking under the truck,it's in park with E brake on too.The 205 will have a bit of gear whine,both mine do anyway,if your shift boot needs replaced,more noise too.I don't have a picture,but the fill plug is on back of case about 1/3 way up & drain is right at bottom if I remember correctly.It's a square headed plug,around a 3/8 or 7/16 wrench?? Hope this helps...

Oldriginal86 · 11-04-2013, 09:13 PM

What transmission is in the truck?

clapage6 · 11-04-2013, 10:25 PM

Thanks rubble, I'll look into that tomorrow night.

The truck has a th400/np205/dana70 i believe rear end. rounder 10 bolt cover

Zane M · 11-04-2013, 11:16 PM

It probably isn't a bad idea to go ahead and disconnect the driveshaft and visually check the ujoints by removing the caps.
I have had driveshafts that had no play, but upon further inspection, one set of roller bearings were shot. The other three "good" sets provided enough support that the typical check for play didn't produce evidence of a bad joint.

11-04-2013, 01:14 PM	#1
clapage6 Registered User Join Date: Aug 2013 Location: San Diego Posts: 111	t-case + Drivetrain concerns and help needed Hi all, I have a good mechanical background however haven't owned anything bigger than my toyota pickup until a few months back when i got my 83 Crew cab drw for hauling desert toys etc around. Also never did much drivetrain work even though...always been a motor-head while someone else jimmied with suspension/gearing etc... concerns/advice/pointers needed: 1. Good sized clunk when going into reverse. I've been seeing around could be U-joints/diff etc. Does anyone know of a decent way of diagnosing the exact cause a "SAFE" way? 2. I can hear the tcase gears spinning though the t-case shifter in the cab at all times... gets a little annoying; not crazy loud but i can def. hear it even with my window down .... is this how all np205's are or is there something else wrong? everything seems tight as far as linkage is concerned? Is there a decent thread anywhere with pics on drain/fill/sight plugs on the 205? I think that's it for now Thanks guys

11-04-2013, 03:20 PM	#2
Rubble Registered User Join Date: Feb 2012 Location: Big Valley. Alberta Posts: 674	Re: t-case + Drivetrain concerns and help needed You can check the u joints by seeing if there is any movement right at the joint.Grab the driveshaft & try to wiggle it back & forth,if there is any movement your joints need replaced. Also look at the caps & see if they are shiny,that means the needle bearings are getting bad& need replaced.If you run down the road a bit,stop & feel the u joints to see which one is hot or warm.You probably know this already,but when your checking under the truck,it's in park with E brake on too.The 205 will have a bit of gear whine,both mine do anyway,if your shift boot needs replaced,more noise too.I don't have a picture,but the fill plug is on back of case about 1/3 way up & drain is right at bottom if I remember correctly.It's a square headed plug,around a 3/8 or 7/16 wrench?? Hope this helps... __________________ 1977 Chev C30 454/465/14ff DRW 1974 Chev C20.350/465/14ff " Rock n Roll ain't noise pollution"

11-04-2013, 09:13 PM	#3
Oldriginal86 Registered User Join Date: Apr 2013 Location: Pasadena, Maryland Posts: 160	Re: t-case + Drivetrain concerns and help needed What transmission is in the truck?

11-04-2013, 10:25 PM	#4
clapage6 Registered User Join Date: Aug 2013 Location: San Diego Posts: 111	Re: t-case + Drivetrain concerns and help needed Thanks rubble, I'll look into that tomorrow night. The truck has a th400/np205/dana70 i believe rear end. rounder 10 bolt cover

11-04-2013, 11:16 PM	#5
Zane M Registered User Join Date: Dec 2006 Location: SLC, UT Posts: 706	Re: t-case + Drivetrain concerns and help needed It probably isn't a bad idea to go ahead and disconnect the driveshaft and visually check the ujoints by removing the caps. I have had driveshafts that had no play, but upon further inspection, one set of roller bearings were shot. The other three "good" sets provided enough support that the typical check for play didn't produce evidence of a bad joint.



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