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If I want to go from a 3.07 rear to a 3.54 or 3.73 on my 84 C4 do I have to change carriers?
If you currently have 3.07 you can buy the 'THIN' Gear. If this '84 is original I'd think it best to acquire another (known to be later) to build unless you can confirm the '84 (in this car) is a very late or maybe a service rear differential.
If you currently have 3.07 you can buy the 'THIN' Gear. If this '84 is original I'd think it best to acquire another (known to be later) to build unless you can confirm the '84 (in this car) is a very late or maybe a service rear differential.
Great info! Will have to do some more research. Thank you!
Great info! Will have to do some more research. Thank you!
I might have information of casting information to check for early '84 builds BUT there was a TSB for cross-shaft retention issues. In '85 the D36 was changed and most '84 that had the cross-shaft issues were replaced. I've no idea where a VIN break for an '84 might be considered to be the later. I'll look. Everything except the housing, rear cover, ring/pinion and pinion flange was/is different.
I might have information of casting information to check for early '84 builds BUT there was a TSB for cross-shaft retention issues. In '85 the D36 was changed and most '84 that had the cross-shaft issues were replaced. I've no idea where a VIN break for an '84 might be considered to be the later. I'll look. Everything except the housing, rear cover, ring/pinion and pinion flange was/is different.
Curious about this as well. When I pulled my rear cover it appeared that my carrier was replaced or at least pulled... there were witness marks on the assembly (pry bar like) with paint pen marks on all the bolts. The gears themselves and everything inside looked good for 30+ years old and 109k miles. My trucks usually showed much worse.
Curious about this as well. When I pulled my rear cover it appeared that my carrier was replaced or at least pulled... there were witness marks on the assembly (pry bar like) with paint pen marks on all the bolts. The gears themselves and everything inside looked good for 30+ years old and 109k miles. My trucks usually showed much worse.
The Recall/Campaign was for this VIN Sequence. E5100001 E5148659 TSB was 84-C-25 and dated 9/1985
Since that was a Campaign you could very likely take your VIN to a GM Dealer and confirm it was done. I have some more information I was trying to get into one file to maybe post but it will take me a while!
I have all of the info in a GM SPO Parts Catalog that would be required to ID but that I'll include with the other.
If you go to a GM Dealer ask them for GM SI Document # 269801 and it will be the 6 page document that I have.
Wish I paid more attention inside... I think my caps are the rounded earlier style.
I'll call my buddy and see if he'll look up if it was done.
The later carrier/posi can be used and likely was if done and the 'short-axles' along with the carrier/posi would have been done. You can't just selectively replace the caps. I have a couple of the later housings and also a couple D36 covers if you decide to do something different. A few $$ plus the ship would work. An early '84 would have just required the different carrier bearings along with carrier/posi and 'short-axles'.
The later carrier/posi can be used and likely was if done and the 'short-axles' along with the carrier/posi would have been done. You can't just selectively replace the caps. I have a couple of the later housings and also a couple D36 covers if you decide to do something different. A few $$ plus the ship would work. An early '84 would have just required the different carrier bearings along with carrier/posi and 'short-axles'.
Good to know. Then maybe it's fine.
I've actually had my eyes on a D44. Guy just wants too much for it. Out of an 85. But it's very local.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by WVZR-1
I might have information of casting information to check for early '84 builds BUT there was a TSB for cross-shaft retention issues. In '85 the D36 was changed and most '84 that had the cross-shaft issues were replaced. I've no idea where a VIN break for an '84 might be considered to be the later. I'll look. Everything except the housing, rear cover, ring/pinion and pinion flange was/is different.
I appreciate the information you're providing in this thread.
My '84 is in the middle of the VIN range. Is there anything external on the rear end that would give us an indication that the service work was done, or is contacting a dealer to check the recall information our only option?
These are the 1st & 2nd design 'short-axle' and the SPO Parts Catalog mentions identifying 1st or second by numbers on the rear cover. I've actually never looked but if a car got correct stuff the first time it could maybe be used. If your cover had 1st design information you would have to look internally I believe to confirm. There would be no short cut. Knowing that the short axles are different I've never known anyone that's checked. The 1459 & 1460 are also used in the '85+ D36.
If you had 1st design info on the cover I think a check with the dealer would be the required check 'UNLESS' you remove the cover and inspect.
These are the 1st & 2nd design 'short-axle' and the SPO Parts Catalog mentions identifying 1st or second by numbers on the rear cover. I've actually never looked but if a car got correct stuff the first time it could maybe be used. If your cover had 1st design information you would have to look internally I believe to confirm. There would be no short cut. Knowing that the short axles are different I've never known anyone that's checked. The 1459 & 1460 are also used in the '85+ D36.
If you had 1st design info on the cover I think a check with the dealer would be the required check 'UNLESS' you remove the cover and inspect.
