4+3 noise
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
4+3 noise
Hi guys,
I'm Max from Italy.
Today I'm going to test a 1987 4+3 convertible C4. It's run great, the OD work well, but when the OD is not engaged I listen a noise...it's like the differential noise (like if there's wrong oil), but if you engage the OD there isn't noise, it's all quite...
The car had 80k miles, but I don't know nothing about gear maintenance...
Someone can tell me what could be this noise? Only when OD is not engaged...
Thanks in advance guys...
I'm Max from Italy.
Today I'm going to test a 1987 4+3 convertible C4. It's run great, the OD work well, but when the OD is not engaged I listen a noise...it's like the differential noise (like if there's wrong oil), but if you engage the OD there isn't noise, it's all quite...
The car had 80k miles, but I don't know nothing about gear maintenance...
Someone can tell me what could be this noise? Only when OD is not engaged...
Thanks in advance guys...
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
Pro
Joined: Mar 2024
Posts: 537
Likes: 379
From: Northern California
I can imagine this issue can happen to all 4+3s, regardless of the year, if they were poorly serviced throughout their life. This is why the fluid changes are so important. Take IHBD’s words, run from this car. This is not the one.
Pro
Joined: May 2025
Posts: 614
Likes: 147
From: OK
I think that's the only problem my 156K 86 doesn't have lol..
I consider a 4+3 car to be buying the fact that it has the heavier rear diff and clutch and such already for whatever trans you eventually upgrade to.
The doug nash setup lasts however long it lasts and then you either pass it on or spend the money on another trans. I'm not looking forward to that
day but it seems to be about the size of things right now. It's still better than an automatic.
One would have to really want the early interior and body and engine (like me) to pick one of em over the later six speed cars.
Be a different matter if they were economically and correctly fixable.
Edit: Just google'd this for the hell of it, is this the bearing?
https://www.transmissionpartsdistrib...4-88-corvette/
I've bought from those guys before and they seemed legit.
I consider a 4+3 car to be buying the fact that it has the heavier rear diff and clutch and such already for whatever trans you eventually upgrade to.
The doug nash setup lasts however long it lasts and then you either pass it on or spend the money on another trans. I'm not looking forward to that
day but it seems to be about the size of things right now. It's still better than an automatic.
One would have to really want the early interior and body and engine (like me) to pick one of em over the later six speed cars.
Be a different matter if they were economically and correctly fixable.
Edit: Just google'd this for the hell of it, is this the bearing?
https://www.transmissionpartsdistrib...4-88-corvette/
I've bought from those guys before and they seemed legit.
Pro
Joined: Mar 2024
Posts: 537
Likes: 379
From: Northern California
The doug nash setup lasts however long it lasts and then you either pass it on or spend the money on another trans.
Edit: Just google'd this for the hell of it, is this the bearing?
https://www.transmissionpartsdistrib...4-88-corvette/
I've bought from those guys before and they seemed legit.
Edit: Just google'd this for the hell of it, is this the bearing?
https://www.transmissionpartsdistrib...4-88-corvette/
I've bought from those guys before and they seemed legit.
plus:
^^^ I believe THIS is the bearing. Carrier and everything. I found this image many moons ago and I guess someone was lucky enough to dig this OEM bearing and carrier out of a parts warehouse somewhere.
Lord knows if any other bearing would work… though it’s certainly possible.
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Melting Slicks
Joined: Nov 2016
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From: So Cal
2023 C4 of the Year Finalist - Unmodified
Last edited by IHBD; Sep 27, 2025 at 12:19 PM. Reason: Bearing I.D. removed
Pro
Joined: May 2025
Posts: 614
Likes: 147
From: OK
I think you may have misunderstood my post. None of that matters, just the part number on the bearing itself to begin the process of verifying that it isn't available. That starts with the bearing, the manufacturers isn't GM, it's Elges.
The bearing can usually be pressed in/out of the housing. Schaeffler owns Elges now so that might complicate things but it's where I'd start.
The bearing can usually be pressed in/out of the housing. Schaeffler owns Elges now so that might complicate things but it's where I'd start.
Pro
Joined: Mar 2024
Posts: 537
Likes: 379
From: Northern California
That is MY picture. That is MY part and my box. Appearances can be deceiving.
You have to be careful looking at things. It looks like it should be a new part. Not only is it a used part, it is a junk part. I should put it on ebay for $900.
Bill Boudreaux in Phoenix Arizona would vehemently disagree with you. zfdoc.com
You have to be careful looking at things. It looks like it should be a new part. Not only is it a used part, it is a junk part. I should put it on ebay for $900.
Bill Boudreaux in Phoenix Arizona would vehemently disagree with you. zfdoc.com
And I guess the 4+3 and ZF guys can relate to one thing; only one guy in the country can fix our transmissions. And we enjoy our third pedals.
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
I don't care about any of this. My 4+3 works. And I have another complete 4+3 on the shelf.
The OP asked about purchasing a car with a noisy DNE carrier bearing. I suggested that he NOT purchase it. Avoid the headaches. Not to mention he's in ITALY.
No one has mentioned the thrust washer. Those aren't available either.
The OP asked about purchasing a car with a noisy DNE carrier bearing. I suggested that he NOT purchase it. Avoid the headaches. Not to mention he's in ITALY.
No one has mentioned the thrust washer. Those aren't available either.
Hi IHBD,
i apreciated your comments and your suggest...i'm so sad, because the car was in good shape and a good price (remember all, i'm in Italy)...but...if there aren't spare parts...Unfortunately i don't know much on maintenance, this car is in italy since 2014 and had 6 owners!!!! Before 2014 was an Austria car....
This is the Vin of the car: 1G1YY3188H5121142
I see 5speed.com had rebuilding kit and bearing, but they are not available at the moment...really sad...
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
I don't care about any of this. My 4+3 works. And I have another complete 4+3 on the shelf.
The OP asked about purchasing a car with a noisy DNE carrier bearing. I suggested that he NOT purchase it. Avoid the headaches. Not to mention he's in ITALY.
No one has mentioned the thrust washer. Those aren't available either.
The OP asked about purchasing a car with a noisy DNE carrier bearing. I suggested that he NOT purchase it. Avoid the headaches. Not to mention he's in ITALY.
No one has mentioned the thrust washer. Those aren't available either.
Nobody try tu put a zf 6 speed in place of the 4+3? It's a possible things?
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
Other question, isn't there the possibilities to replace the 4+3 gearbox with a standard 5 or 6 gear shift?
Thanks
Instructor
Joined: Jan 2021
Posts: 146
Likes: 37
Don't buy the car
If you really want it, get it and realize you'll need to swap something in it. Maybe you can get it cheap enough to justify yanking the trans and swapping. I don't know what you can get in Italy, but a TKX is the best swap here in the states, a T5 if you like to live dangerously but those are getting harder to find.
My 4+3 works still at 125k, but if it ever goes its getting a TKX or the car is getting junked. They're unrepairable at this point.
If you really want it, get it and realize you'll need to swap something in it. Maybe you can get it cheap enough to justify yanking the trans and swapping. I don't know what you can get in Italy, but a TKX is the best swap here in the states, a T5 if you like to live dangerously but those are getting harder to find.
My 4+3 works still at 125k, but if it ever goes its getting a TKX or the car is getting junked. They're unrepairable at this point.
Pro
Joined: May 2025
Posts: 614
Likes: 147
From: OK
Cannot effectively run it with the overdrive always on. The pump is on the output shaft of the OD unit so until it's spinning enough it will not make enough pressure.
We usually do the opposite here, disable the computer control and just use it as a 5th overdrive gear manually with the switch to minimize wear on them.
There really is not a fool proof solution other than replace the trans with something else. You might find a good used one, or you may not need the unobtainable
parts (it's a very simple unit otherwise). Pretty much buying something with an expiration date on these.
We usually do the opposite here, disable the computer control and just use it as a 5th overdrive gear manually with the switch to minimize wear on them.
There really is not a fool proof solution other than replace the trans with something else. You might find a good used one, or you may not need the unobtainable
parts (it's a very simple unit otherwise). Pretty much buying something with an expiration date on these.
Thread Starter
Instructor
Joined: May 2008
Posts: 118
Likes: 2
From: Arconate (MILANO) ITALY
Don't buy the car
If you really want it, get it and realize you'll need to swap something in it. Maybe you can get it cheap enough to justify yanking the trans and swapping. I don't know what you can get in Italy, but a TKX is the best swap here in the states, a T5 if you like to live dangerously but those are getting harder to find.
My 4+3 works still at 125k, but if it ever goes its getting a TKX or the car is getting junked. They're unrepairable at this point.
If you really want it, get it and realize you'll need to swap something in it. Maybe you can get it cheap enough to justify yanking the trans and swapping. I don't know what you can get in Italy, but a TKX is the best swap here in the states, a T5 if you like to live dangerously but those are getting harder to find.
My 4+3 works still at 125k, but if it ever goes its getting a TKX or the car is getting junked. They're unrepairable at this point.
There's a website to see these gearbox?
I don't understand what is the piece in the OD that create all this problem...can you show me a picture?
Thanks