GM #3886960; question for Joe Lucia

[Gary B.]

Joe,

Some years ago on the BD you described the mid-65 thru 70 driveshaft U-joint Used in production as:

46C01FD0-FC2E-4D9A-80FD-7D7D7D4AAE19.jpg

[Joe L.]

Re: GM #3886960; question for Joe Lucia

Joe,

Some years ago on the BD you described the mid-65 thru 70 driveshaft U-joint Used in production as:

“During this period, Corvettes used driveshaft u-joint GM #3889690. This u-joint had a "square" trunnion design with square indentions on both sides of the center of the trunnion.“

I’m trying to imagine what the square trunion and square indentation looked like. Does the U-joint in the attached image look something like what you described?

Gary

[ATTACH=CONFIG]99615[/ATTACH]

Gary------

Exactly as I described.

[Brad Hillhouse (37766)]

Re: GM #3886960; question for Joe Lucia

Joe - I have seen the 1310 series Ujoint used in the drive shafts of 1967-1969s with the indented circle on each side but never this square version. Is this just a different variation from a different manufacturer?

thank you

Brad Hillhouse

[Gary B.]

Re: GM #3886960; question for Joe Lucia

Brad,

Based on examples I’ve seen on the BD, the circular indentation certainly existed prior to mid-65 and more recently the GM/Spicer joints had circular designs. I’ll defer to Joe on the time frame for the square indentation design.

The example of the U-joint in the image I showed was an aftermarket unit made by Precision, I think.

Gary

[Joe L.]

Re: GM #3886960; question for Joe Lucia

Joe - I have seen the 1310 series Ujoint used in the drive shafts of 1967-1969s with the indented circle on each side but never this square version. Is this just a different variation from a different manufacturer?

thank you

Brad Hillhouse

Brad------


Yes, I have seen GM u-joints with the round center depression on both sides. However, I do not know of what part number they were since they were used u-joints and not identified in any way by part number. I have observed an NOS GM #3886960 which was configured very similar to the joint pictured above. It's very possible, though, that there were different configurations of u-joints of the same GM part number. At the time, GM was using these u-joints by the millions. I know that some were of GM internal manufacture, some were manufactured by Spicer, and, likely, there were other manufacturers, too.

For example, I have many NOS examples of the 1350 series half shaft u-joints GM #3889696 [none for sale]. Some are in the old GM black and yellow boxes. Some of these are clearly of GM internal manufacture and some are clearly of Spicer manufacture. There are slight differences in their configurations not related to functionality but all are the same GM #3889696 part number.

There were many different part numbers for the 1310 series u-joints over the years. These include but are not limited to GM #3713926, 3830580, 3849500, 3889690, 3955571, 2448382 and likely more.

By the way, the GM #3713926 had the center round depressions. However, I highly doubt this part number was still being used as of 1967-69. Of course, other later u-joints may have had the same configuration.

[Brad Hillhouse (37766)]

Re: GM #3886960; question for Joe Lucia

Joe -

I grew up in a Radiator & Drive Shaft shop and have been doing research on Corvette U-joints to put on a judging school. It looks like from this thread and others you have previously posted, that maybe you already have all the information needed. Have you put together a presentation of some sort on driveline related information?


Brad

[Joe L.]

Re: GM #3886960; question for Joe Lucia

Joe -

I grew up in a Radiator & Drive Shaft shop and have been doing research on Corvette U-joints to put on a judging school. It looks like from this thread and others you have previously posted, that maybe you already have all the information needed. Have you put together a presentation of some sort on driveline related information?


Brad

Brad-------


I have not developed any presentation or paper on u-joints. U-joints can be a very confusing subject. That's because there has been a virtual plethora of part numbers over the years. For example, the u-joint you picture, GM #7806140, was preceded by GM #5677655 which was discontinued in January, 1971. There were probably several other part numbers predecessor to the 5677655. The GM #7806140 was discontinued in March, 1997 and replaced by GM #26042371. There were several part numbers following that culminating in GM #23104840 which is the current part number. They'll probably be more supercessive part numbers as time goes on. In addition, many of the u-joint part numbers for functionally the same part co-exist for certain periods of time adding to the confusion.