Rear End lets go after only 300,000 miles !

[Harry S.]

Re: Rear End lets go after only 300,000 miles !

This thread and, in particular the degree of damage to Jack's C2 diff has my attention. Is this degree of catastrophic internal damage typical or the exception to the norm? My '64 with 4::11 posi is making noise - is it at all safe to drive (just drive not abuse) or am I risking a major blow-out like Jack experienced? Granted I have far fewer miles than Jack, I have good reason to believe this original diff has less than 70K miles. Yes, I do plan to have the diff completely overhauled / rebuilt but I would like to drive it a bit before having the rear suspension dismantled for 3 months or more.

Ed, just make sure everything is tight on the differential, especially the bolt on the pinion gear. If that comes loose and slides in you end up with Jack's problem. I had the same problem as Jack but not as bad. I just had to replace the posi. unit. Also, change the fluids.

If you look at post 21 in this thread, that is what happened to me.

[Jack P.]

Re: Rear End lets go after only 300,000 miles !

Hi Ed
Gary would like to talk with you if you can call him I would appreciate it. You can reach him at. 203 776 2813 ex 139

thanks

jack

[Jack P.]

Re: Rear End lets go after only 300,000 miles !

My problem was the posi cracked and expanded into the pinion gear , pieces then jammed spider gears and just a few yards of movement of car sealed the faith of rear. I should have stopped driving the car, but I let my son drive it to hear the noise, he goosed the gas and bang!


It happened in my driveway at less then 15 mph (long driveway)

Jack

[Edward J.]

Re: Rear End lets go after only 300,000 miles !

Ed, Rear Diff. problems can be more than area. Bearing noises are the most common, and depending on just how much noise is whether or not to drive. when a bearing is gone the rear diff. you generally hear a humming and tends to get noisier with speed. gear noise is more of a whine noise and can tend to be noiser with acceleration, decelerating or coasting. Another common issue is posi. chatter, this happens when turning in tight circles, generally will make a noise, this is a slip and grab situation, this condition is a lack of limited slip additive or not enough.

[Edward J.]

Re: Rear End lets go after only 300,000 miles !

Hi Ed
Gary would like to talk with you if you can call him I would appreciate it. You can reach him at. 203 776 2813 ex 139

thanks

jack

Jack, is this his cel phone? does he mind If I call him tomorrow? or Monday? What are his hrs., I can call tonight.

[Jack P.]

Re: Rear End lets go after only 300,000 miles !

Hi Ed , that is his work number Monday would be ok pm your number or cell and I will send it to him

Jack

[Edward J.]

Re: Rear End lets go after only 300,000 miles !

Jack I sent it email , your PM box is full.

[Jack P.]

Re: Rear End lets go after only 300,000 miles !

Just emptied it and have sent your numbers to Gary

Jack

[Ed S.]

Re: Rear End lets go after only 300,000 miles !

Jack,
I am assuming that it is Edward "Ed" Johnson that Gary wants to talk to or......, is your request to call Gary for me, Ed Szeliga.

[Jack P.]

Re: Rear End lets go after only 300,000 miles !

Yes , Ed Johnson , but if you need help, Gary is the one to call, if you can wait a while ...

[Gary R.]

Re: Rear End lets go after only 300,000 miles !

Hi Jack, Ed, Guys
Some information for you on Jack's diff issue and 63-79 vette diff's in general.

Jack had a 1968 complete differential in his '66 for the past 45 years. The '65-68's used the 1st design Eaton Posi case in place of the Dana posi used in 63-64. Keep in mind posi was optional until 1970 so there are some open differentials out there still. They were stronger then the Dana posi and I think equal to the Eaton 1st design.

The Eaton 1st design can be ID'd by looking at the case, they have what I call the "postage stamp" window in them. They were a parallel seam casting and this design was prone to cracking at the seam to large window opening. This casting are rough with sharp edges that are stress risers and with abuse or time the cracks form. Once a crack is started then it's a time bomb. Weld or drill repair does not work out well once a crack is there, the only solution is to replace the posi case with the better 2nd design Eaton case used from 1969 -1979 and still sold in the aftermarket today. The 2nd design can be ID'd again by the window, in this case a larger "tear-drop" window. These have a single staggered tooth seam and are much less prone to cracking but they still crack. When ever I build a diff I polish and tune the posi's to cut down on this from happening. I also have them cryo treated for HP applications.

In Jack's case the posi case developed a crack, who knows when, could have been in 1983 when Jack was burning rubber, could have been driving across the country, who knows. The only way you will know is to remove the diff and check it. However I have heard posi's getting ready to break by a clicking sound. I don't know if Jack heard that, I think he said he did when he came in last week but he would know better. My son heard it before his posi case broke in 1/2 on the street. Once the crack reached the cross shaft hole it was over. That is when I think it starts to click as play in the cross shaft and spider pinion gears increases. Then the gears will jam up and lock the posi and break. Jack's locked up and spun into the pinion "milling" it down in a second. Once the case broke it expanded inside the housing and really jammed up. It wrecked the RH axle and bearing and that is why I don't trust the housing. I have seen them break before but they usually shear and become loose parts inside the housing. Then when I open them up the parts fall out. Jack's was just the opposite. It was wedged so tight it was like having a case spreader on it and still wouldn't come out until I torched it out.

Ed Johnson I may be in the shop later today. If you want me to call you when I get in just PM me your number.

Ed S - if you have any questions I can help you with let me know.

Thanks Guys
Gary

[Edward J.]

Re: Rear End lets go after only 300,000 miles !

Gary, If you have a I-phone ,just send me a pm and I will send you a few Pic.s of what I have, I just want you know I am not trying to take anything away from what you are doing for Jack, this unit I have a working unit with no noise at all. and likely can be a temporary unit or if jack wants used for parts.

[Jack P.]

Jack is very happy with new rear end !!

Gary, If you have a I-phone ,just send me a pm and I will send you a few Pic.s of what I have, I just want you know I am not trying to take anything away from what you are doing for Jack, this unit I have a working unit with no noise at all. and likely can be a temporary unit or if jack wants used for parts.

Hi Ed, thanks for talking with Gary, it looks like we are all set for me to use the 78 rear end. I will give you a call after the basketball game .....or on Monday.....

I have some thing to pay forward, if anybody needs a complete set of struct rod bushings (small) for c-2, I have a 4 of them that was given to me to put in my rods. My rods are bent and different one (sm & bg) rods, so I am getting a new set of rods with the bushings installed.

If you need a set let me know and I will send them to you for FREE....

Jack

[Jack P.]

Re: Jack is very happy with new rear end !!

Hi to all,


I made a quick ride to Easton, MA , where a good friend , Ed Johnson owns a home town service and repair shop .


Ed had graciously donated a late seventies corvette differential to my car. It has a 3:70 in it, but I will have that changed out (3:36) by Gary Ramadei, of New Haven , CT , who is going to rebuild and tune it for me.


I will box it up and send it to him this week.


Here are few pictures of Ed and his good friend Bob, (owns a 63) who helped with the transfer. If you ever need mechanical work done just south of Boston, give Ed a call....508-238-9455


Ed & Bob in his shop





Here she is .....

[Jack P.]

Looks a lot better than this one...

Here is the one that I blew up





Gary had to burn it out