'72 U-joints...Flat capped or recessed?

[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

Joe, do you have a 3832031 or 3872922 ; both are listed in 1942-1965 chevrolet parts catalog as 1963-65 corvette diff. carrier U-joint. Strangely the later # is listed as 65 corvette w/P/Trac ? Also do you have a 3889696, from 1974 corvette parts catalog ? All are half shaft joints.

Mark------


The GM #3823102 was generally used for 1963 Corvettes although, as always for these kind of parts, there could have been carryover to 1964. It was discontinued in January, 1965 and replaced by the 1964-65 u-joint, GM #3851520. The latter was discontinued in November, 1965 and replaced by the 1965-66 u-joint, GM #3877040. I do not possess any of these u-joints.

The GM #3877040 was discontinued in January, 1966 and replaced by GM #3889696. The latter was used for 1966 to 1979 as well as 1980-81 with manual transmission and all 1982.

I have many NOS examples of the 3889696 [none for sale]. Most of mine are the same as those in the first pictures, below. I have one that was packaged a little differently and configured slightly differently. The first one pictured (and 4 others I have just like it) has no boss for a zerk joint on the trunnion and has a Chevrolet "bow tie" embossed on the trunnion. This indicates that it was of internal GM manufacture. The second pictured and differently boxed example has an untapped boss on the trunnion for a zerk and has no Chevrolet "bow tie" on the trunnion. Otherwise, it's identical to the first.

The GM #3889696 was discontinued in April, 1983 and replaced by GM #374246 and, later, GM numbers 7834387, 26049843, 12471503, and 89059111.

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[Mark M.]

Re: '72 U-joints...Flat capped or recessed?

I too appreciate your detailed history on parts Joe. Joe the joint you show 3889696 with the bowtie looks like a set I found and used on a 67 L68 car. National and Bloomington judges appreciated them. The second one with the boss seems to have caps with different diameter recesses or is that what the machining left on a concave cap? I have some NOS spicers and I believe they have a deeper recess cast in. Somewhere in c3s the recess seems to have started.

[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

I too appreciate your detailed history on parts Joe. Joe the joint you show 3889696 with the bowtie looks like a set I found and used on a 67 L68 car. National and Bloomington judges appreciated them. The second one with the boss seems to have caps with different diameter recesses or is that what the machining left on a concave cap? I have some NOS spicers and I believe they have a deeper recess cast in. Somewhere in c3s the recess seems to have started.

Mark------


The other caps on the first u-joint I pictured have varying diameters of the "depression". The depth on the cap pictured in my previous photo is 0.0125". On the cap pictured below, the depth is 0.009". I'm sure this varied based on the amount of machining the end of the raw casting required to get the cap within finished spec.

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[Gary B.]

Re: '72 U-joints...Flat capped or recessed?

I have a March 2nd built 1971, very original car on the hoist. Both U-joints are dimpled.
I have access to an early 70, if the weather holds out for a few days, I'll look at it.
Gary B

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[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

I have a March 2nd built 1971, very original car on the hoist. Both U-joints are dimpled.
I have access to an early 70, if the weather holds out for a few days, I'll look at it.
Gary B

[ATTACH=CONFIG]114540[/ATTACH]

Gary------


These are a different series u-joint than any of those I pictured above. If the 1970 model has a THM-400 transmission it will have the same u-joints as those you pictured. If it's a 4 speed, it will have u-joints of the same series as I pictured in my first post in this thread.

[Gary B.]

Re: '72 U-joints...Flat capped or recessed?

Thanks Joe. Didn't 70 TH400 and all 71-72 (both manual and TH400) use the same u-joint.
I have an Illustrated Parts Manual dated 7-71, it shows:
64-69 used 3889690
68-70 TH400 and all 71 used 390133
69-70 (exc TH400) used 3955571
So the picture I posted today would be a 390133?
Group 5,548
Gary B

[Gary J.]

[Terry M.]

Re: '72 U-joints...Flat capped or recessed?

I have a March 2nd built 1971, very original car on the hoist. Both U-joints are dimpled.
I have access to an early 70, if the weather holds out for a few days, I'll look at it.
Gary B

If you are going to visit that early 1970 on Friday I'll come help you. I have an ulterior motive, as you can guess.

[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

Thanks Joe. Didn't 70 TH400 and all 71-72 (both manual and TH400) use the same u-joint.
I have an Illustrated Parts Manual dated 7-71, it shows:
64-69 used 3889690
68-70 TH400 and all 71 used 390133
69-70 (exc TH400) used 3955571
So the picture I posted today would be a 390133?
Group 5,548
Gary B

Gary-----

As far as driveshaft u-joints go, it's like this:

1953-67 all Corvette-----------------------1310 series u-joints (formerly known as 1280 series)

1968-70 Corvette with manual trans------1310 series u-joints (formerly known as 1280 series)

1968-70 Corvette with THM400-----------1330 series u-joints

1971-79 all Corvette-----------------------1330 series u-joints

The u-joints you picture should be of GM #390133 which was a 1330 series u-joint.

As far as half shaft u-joints go:

1963-79 all Corvette-----------------------1350 series u-joints

Within any series u-joint, there could have been multiple GM part numbers all of which would be functionally interchangeable

[Gary B.]

Re: '72 U-joints...Flat capped or recessed?

Thank you Joe. I'll update the 70-72 and 68-69 TIM&JG's.
Gary B

[Robert N.]

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[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

Here are some photos of two NOS GM #390133 u-joints [none for sale]. You will note that both are Spicer-manufactured u-joints. However, it is possible that some 390133 were manufactured internally by a GM Division or by other manufacturers. I kind of doubt it, though. My strong inclination is that the 390133 was always a Spicer-manufactured u-joint. That's partly due to the part number. I just don't see a 390133 part number being assigned as early as 1969 to a GM-manufactured part. Based on the labeling, both of those shown below are quite old, probably dating back to the 70's.


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[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

Here's another interesting NOS u-joint. This one is a GM #3937988. It was never catalogued for a Corvette application but it was a predecessor part number for the 390133. It was discontinued and replaced by the 390133 in August, 1971 so the example shown cannot be more recent than that date and, likely, older. I would not be surprised if this part numbered u-joint was actually used in PRODUCTION for some 1968-69 Corvettes with THM400.


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[Joe L.]

Re: '72 U-joints...Flat capped or recessed?

Here's another:

U-joint GM #3851520 was catalogued for the driveshaft application for 1964-65 Corvettes and replaced GM #3823102, the 1963 u-joint, in January, 1965. The 3851520 was discontinued in November, 1965 and replaced by GM #3877040, the 1966 u-joint. Thus, the particular NOS example pictured [not for sale] has to be from the period of about January, 1965 to November, 1965. There is no indication on this u-joint of a manufacturer's ID. The trunnion only has the number "8617" embossed on one side. If you're wondering why the bearing caps of not installed on the trunnion, that's because these early u-joints were supplied that way. The needle bearings in the caps were retained by a small cardboard cylinder which was to be removed when the caps were installed on the trunnion. Incidentally, bearing caps were once available from GM separately, too. I could never figure out why anyone would just replace a cap rather than the complete u-joint. To me, that's asking for trouble.

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[Gary B.]

Re: '72 U-joints...Flat capped or recessed?

You are correct. A 71 very original car.
Gary Bosselman

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