noisy nv4500

[brian wafer]

installed a used nv4500 in our 1977 3/4. seems transmission is noisy when idleing and clutch pedal not depress. are they noisy or should i get a bearing kit? i have the right oil. will try a can off gear dope!

 

[sweetk30]

known for input bearing problems . that's why lots of guys 1/2 quart over fill them . this helps lube them at that bearing better.

but sounds like your going to have to check it out for sure.

 

[dixiechevy01]

Was the clutch used or new? You may have some worn out or loose parts in the clutch. And is it shifting ok?

 

[Hogback Fabrication]

I would bet input gear and/or pilot bearing issues.

 

[Larry]

Put me down .25 cents for a release bearing. 3 of the 4 manual trans trucks I have all have auditable rattily release bearings at idle (2 NV4500’s and 1 ZF S6-650). The only truck I have that doesn’t rattle is our old Toyota 4Runner. The 465’s that were in my K10 and Suburban both had rattily release bearings as well even before they got NV4500 infusions. Seems nobody makes a decent release bearing these days.

With your swap did you use an internal slave/release bearing assembly or an external slave? If external you might be able to add some adjustment to the rod to put a little tension on the release bearing to mitigate the noise or even take it away completely if you are lucky.

 

[DEMON44]

Yep pilot bearing or input bearing. Release bearing should only be turning when clutch peddle is pushed in though. If though sound changes when pushing the clutch in and out when idle in neutral. You can narrow it down.

Was this a retro fit swap? Or a straight r and r? Do you have the correct pilot bearing installed?

 

[Larry]

Yep pilot bearing or input bearing. Release bearing should only be turning when clutch peddle is pushed in though. If though sound changes when pushing the clutch in and out when idle in neutral. You can narrow it down.

Was this a retro fit swap? Or a straight r and r? Do you have the correct pilot bearing installed?

Negative, release bearings can make noise at idle with no load on the clutch (pedal up) when the bearing is just free-wheeling. It is the most common release bearing noise there is. The noise can be caused by the release bearing rattling on the shift fork clip, improperly installed release bearing where it is not clipped into the clutch fork correctly or it just a noisy unloaded release bearing. By slightly stepping on the clutch will put just enough pressure on the release bearing to quiet it up by tightening up any excessive free play.

To a certain degree, release bearing noise is actually considered normal by many accounts. My 2001 Silverado with the ZF 6 speed has done it since the day it was new and gets much worse as the transmission (and release bearing/slave assembly) gets warmer. GM has had several bulletins over the years that discuss release bearing rattle. The first thing the bulletins always say is to NOT tear into the transmission. When I worked on the Chevrolet Technical Assistance hotline in the late 90’s in Detroit we used to get a lot of calls on this subject. Most of the time the noise was just considered a normal characteristic even though some vehicles make zero noise and others are very noticeable.

Here is a bulletin by a clutch supplier Valeo related to release bearing noises.

You’re correct though, a worn out release bearing will make a lot of noise and produce a vibration when the clutch is depressed (down). There are two different type of release bearing noises and to me brian’s is a typical unloaded release bearing noise which might even be considered normal. Personally I hate release bearing idle rattle but like I said above, 3 of 4 of my rigs do it. All the rattlers are GM too

 

[DEMON44]

The only time I've had a nv4500 rattle on me. Was after I put in a solid hub 13" dual disk clutch. It was amusing how often strangers would tell me there was something wrong with my truck.

 

[Larry]

ya that will cause a rattle too. I’ve been twisting wrenches for 25 years and have heard plenty of rattles that sound like internal transmission problems or even internal engine noise when only a release bearing rattlign around. Not just on NV4500’s but on just about any manual trans model you could think of. I’ve even seen them where they even sound like the engine has a rod knocking.

Medium duty and class 8 trucks really rattle big time. Right now the company I work for has been dealing with release bearing rattles on one model of class 8 semi we build with an Eaton automated manual transmission where the bearings themselves are being replaced with a new design bearing. They only rattle at idle with the clutch released (up). They are so loud you can hear the rattle over a 13L diesel engine

 

[DEMON44]

I have a dislike for autoshifts.

 

[brian wafer]

thanks for the responds. its a kit we got from advance adapters,so we could keep our macanical clutch system. clutch is new 12inch so is pilot bearing. was out on a road test,truck isn,t ready yet. won,t be ready for a while too doing this in spare time!will try extra oil and a can off dope! how could i tell if its a release bearing rattle,any way too know for sure ! my brother did the preperation of transmission in april(if memory is good) . there was a new bearing and imput shaft in kit. input shaft was 1 inch longer, too make room for 1 inch adapter plate to bolt our macanical bell housing. when we installed transmission we could not get clutch too release, had it in and out 5 times, the 4 time with no pressure plate only clutch on imput shaft ,and still it wouldn,t release!!! thats when we notice if we slacken bolts a bit transmission would turn. so we removed about 1/8 of and inch on input shaft ,and finaly got a clutch pedal release. but maybe it but some stress on bearings!

 

[80' 427]

My nv3500 used to rattle at idle in neutral. It is the impulses of the engine.

 

[DEMON44]

Is it bolted up properly right now? Measure crankshaft end play. And report back

 

[brian wafer]

yeah its bolted and had it out on a road test last week. was kind off scared that we had damaged something,but motor seems too run ok. will check backlash but kind off busy these days,will take a while. the noise isn,t coming from motor because its stops when you push clutch pedal in. still got too install hood and paint front fenders,than finish transmission cover. order a new rubber floor mat,not in yet. all this and summer holidays will bring us in september before we can finish truck.maybe put a few miles on truck before winter. hopeful will find our problem,and get it repair this winter. when its slower. really don,t need this truck but me and my brother started driving in it,its like part off the family, dad bought it new!

 

[DEMON44]

Measure endplay not backlash. And yes if your input shaft is too long you will be pressing against your crank thrust bearing. You will take the crank out in short order, if you have no end play. If there's preload on the input shaft you're also putting a beating on the input bearing.

 

[brian wafer]

i meant end play! its not putting pressue anymore since cutting input shaft. we put a dabb of grease and bolted it down, took it back out and grease didn,t transfer.

 

[DEMON44]

It's not the tip that's a concern. The length It puts pressure through the pilot if its too long.

 

[Larry]

Brian,

What exact Advance Adapter part numbers did you use? I assume your truck is a 4x4 but you never really said for sure. If 4x4, what year, spline count and model of transfercase are you using?

I’ve done two NV4500 swaps using AA bellhousings and never had to cut anything on the input shaft. However, on my K10 with the 27 spline 205 tcase I had to cut the NV4500 mainshaft where it connects to the transfercase.

I used kit AA kit 27-0031 for my K10 and 712576 bellhousing on my Suburban. The kit in the K10 uses the same bellhousing as used on the Suburban, which that bell can be used for mechanical or hydraulic clutch operations. No cutting of anything is required to use that bellhousing. With that, I still believe you have a release bearing issue but now I am having a hard time following what exactly you have done to this thing. You might need to get the truck to a shop to have it look at unless you can find a CK5 member close by with experience in this kind of thing. Good luck my friend

 

[brian wafer]

no worry we own a general repair shop. i,m home don,t really have my bill off sale here for part numbers. but will try to explain! the problem is that we have a 6.2 diesel, to be able too keep our 12 inch clutch and longer diesel starter nose and mecanical clutch. the counter guy (vic) suggested we go this way. started by replacing transmission input shaft for a dodge model which is 1 inch longer too make room for a 1inch adapter that bolts our 1977 bell housing too the nv4500. that way we keep our original bell housing and clutch pedal assembly. now when we first bolted to engine we had a clutch pedal but transmission didn,t release,when we turned it by hand. first though was wrong clutch . until we install transmission with out a pressure plate only clutch disc. could see in through out fork hole(it was removed) that clutch disc had room. but still couldn,t turn transmission by hand. thats when we notice main shaft was to long,and cut a piece off! then transmission would turn.(truck was never driven this way) . once all back together we finaly had a cluch pedal that would release. behind transmission we got another adapter plate with a sleeve to adapte our 205 too nv4500. all parts came from advance adapter i will get part numbers tomorrow. the noise is heard in neutral with clutch out,so maybe release bearing chatter and the fact a 6.2 does vibrate more,than a 350. come too think of it the dodge longer imput shaft kit was turned down . by advance adapter so we could use a gm throw out bearing!!!

 

[brian wafer]

hopeful you guys arn,t all mixed up now !!! next time we work on it, will feel the throw out fork by hand too see if it vibrates. and check end play for safety! but after cutting tip we could turn transmission easly by hand. its sitting over our old pit maybe take a picture tommorrow.