Reverse And 2nd To 3rd Clunk

zedbear · November 6, 2009

Hello all. I recently bought a 2000 Sierra Z71 ext cab. I'm having an issue with clunking when shifting into reverse, during the 2-3 shift and the 3-2 downshift. I've done some lurking on here and other sites and found a lack of grease on the driveshaft slip yoke to be a common cause of this. I went out and bought some high quality marine grade wheel bearing grease to use for the slip yoke. Just wondering how much I should use and also if there could be another problem causing this "clunk". U joints appear to be ok when i checked them out real quick the other day but I'm no expert. Thanks!

PS, it never clunks when shifting into drive.

zedbear · November 6, 2009

Anyone?? I saw a topic regarding this greasing procedure but it wasn't clear as to how much to put in......

sternforpres · November 6, 2009

The transmission is most likely the real issue here. No telling how close you are to failure, but I would not flush the tranny fluid unless you have 2k in your pocket for a tranny rebuild.

Greasing the yoke may quiet the noise, but its only a symptom. Search for my posts or search "clunkerado". I just rebuilt my 2000 GMC 2WD...its silky smooth now...

AVortec · November 6, 2009

I just added a "bunch" of marine grade grease to my "clunk-o-lanche" on the splines. This is my 4th attempt with various greases. She still clunks I'm going to live with it I guess. The thought of having to rebuild a tranny at 33,000 miles makes me sick. I'd like to think it's normal (but wrong) driveline lash and not a transmission issue. As far as how much grease to add I'm not really an expert - mainly because I'm still clunkin'. I've read that you need to make sure all the valleys in the splines have a good coat on them. I used a small foot-long wooden dowel and swirled around a bunch maybe the size of a golfball and spread it around good.

kawtoy_77 · November 6, 2009

I gues there is a service letter or something at dealerships that say noise during the 2-3, and possibly 3-4 shift is normal....I belive they are only talking about an upshift though. I had checked into this earlier this year actually b/c my 2-3 upshift made the slightest shudder.... (it took the mechanic and service manager 3 test drives to finally notice what I was talking about) it seems like it comes and goes too. not had any problems with it though other than that..... noise went away by itself.

zedbear · November 6, 2009

The transmission may be shot? That's the first I've heard of that as a possibility. Might be time to take it back to the place I bought the trucks from. Unreal.

I looked at the "clunkerado" thread. Mine clunks into reverse everytime, not just sometimes. Never when putting it in drive. And it only clunks on the 2-3 and 3-2 shift. Never 1-2, 2-1. Transmission seems to be working normally otherwise.

Stevens03 · November 6, 2009

I don't think it's your trans. Theres a few possibilities.

Re-pack your slip yoke with grease. And while you have the drive shaft out, inspect/replace the u-joints. Also, the clatter could be coming from your Lockers if you have factory lockers. I had some loud ones in my 03. Check the fluid in your rear end and see if its low. I'd even replace it for piece of mine and make sure you get what GM put in there.

Good luck and report back.

zedbear · November 6, 2009

I don't think it's your trans. Theres a few possibilities.

Re-pack your slip yoke with grease. And while you have the drive shaft out, inspect/replace the u-joints. Also, the clatter could be coming from your Lockers if you have factory lockers. I had some loud ones in my 03. Check the fluid in your rear end and see if its low. I'd even replace it for piece of mine and make sure you get what GM put in there.

Good luck and report back.

Well, I spread some of that grease around inside the slip yoke. Not sure if I put in enough or too much. It was pretty tight when I slid the shaft back in ( ) so maybe it was enough. There was no grease at all in it when I removed it. Noticed the rear U joint is pretty new and a greaseable one. The front ujoint/slip yoke combo appears to be original although it says "Spicer" on it.

I'm still getting the reverse clank. The 2-3/3-2 shifts seems a bit more muted but could just be my imagination. Still get an annoying pop sound when first accelerating from a stop.

I had the wife get in the truck and put it in reverse a few times while I looked under with a flashlight. It seems like the front u joint is moving a little when it goes into gear but it's very hard to tell for sure. With the shaft out, I couldn't detect any play in that u joint. The "clank" is definetly coming from the t-case area or the slip yoke/ujoint. I could feel the clank through the t-case housing (the part I could reach without going under the truck). Don't think there is any sound coming from the rear end.

I do have the G80 rear end. I think I may replace both the rear diff and t-case fluids. I have to figure out how to verify the front ujoint is moving. With the shaft out, it seemed tight so IDK. The clank sounds sorta like a bowling ball striking a pin. Best way I can think of to describe it.

AVortec · November 7, 2009

I think a muted clunk is not your imagination. I noticed this on mine as well. I was just whinin' because it didn't go away completely. If it helps, my friend bought a 2000 Silverado with 50,000 miles back in '05. He traded it in a few months ago with 139,000 miles on it. He said it had a 3-2 clunk the whole time he owned it and besides being a little bit of noise, nothing happened to the truck.

zedbear · November 7, 2009

I think a muted clunk is not your imagination. I noticed this on mine as well. I was just whinin' because it didn't go away completely. If it helps, my friend bought a 2000 Silverado with 50,000 miles back in '05. He traded it in a few months ago with 139,000 miles on it. He said it had a 3-2 clunk the whole time he owned it and besides being a little bit of noise, nothing happened to the truck.

No, I meant the clunk seemed to be MORE muted AFTER I greased the slip yoke but it may not be. Could just be a "placebo" effect.

sternforpres · November 7, 2009

I didn't have a 2-3 clunk, but it could still be the same symptoms, just different gears.

Try putting it in Tow/Haul and you should REALLY hear it clank, or just tow a boat.

I don't have any proof, but I think these clanks come from something slipping inside and the brain sending maximum pressure and "clank".

My clank into reverse happened every morning, but if I went from park to reverse several times in a row, I might not get the clank every time...if it was warmed up, it would rarely clank into reverse.

clemsonblozz · November 8, 2009

I didn't have a 2-3 clunk, but it could still be the same symptoms, just different gears.

Try putting it in Tow/Haul and you should REALLY hear it clank, or just tow a boat.

I don't have any proof, but I think these clanks come from something slipping inside and the brain sending maximum pressure and "clank".

My clank into reverse happened every morning, but if I went from park to reverse several times in a row, I might not get the clank every time...if it was warmed up, it would rarely clank into reverse.

your sun gear is about to strip out on your shell.. I had two fail, and it started with the clunk between 2-3 and alot of slop when shifting into reverse..

P71_CrownVic · November 8, 2009

Hello all. I recently bought a 2000 Sierra Z71 ext cab. I'm having an issue with clunking when shifting into reverse, during the 2-3 shift and the 3-2 downshift. I've done some lurking on here and other sites and found a lack of grease on the driveshaft slip yoke to be a common cause of this. I went out and bought some high quality marine grade wheel bearing grease to use for the slip yoke. Just wondering how much I should use and also if there could be another problem causing this "clunk". U joints appear to be ok when i checked them out real quick the other day but I'm no expert. Thanks!

PS, it never clunks when shifting into drive.

I'v got nothing more to add except welcome!

zedbear · November 14, 2009

Hello all. I recently bought a 2000 Sierra Z71 ext cab. I'm having an issue with clunking when shifting into reverse, during the 2-3 shift and the 3-2 downshift. I've done some lurking on here and other sites and found a lack of grease on the driveshaft slip yoke to be a common cause of this. I went out and bought some high quality marine grade wheel bearing grease to use for the slip yoke. Just wondering how much I should use and also if there could be another problem causing this "clunk". U joints appear to be ok when i checked them out real quick the other day but I'm no expert. Thanks!

PS, it never clunks when shifting into drive.

I'v got nothing more to add except welcome!

Fancy meeting you here! ^^^^^

I had the wife shift into and out of reverse several times again while I watched under better lighting conditions. Now it seems there isn't any slop in the u joint. But with my hand on the t-case, I can clearly feel the slop and noise is coming from there. It could still be the slip yoke but I don't see why the grease didn't help at all if thats the case.