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3/09/2020 12:12 PM  #26

Re: Installing 9” in my 66

MS wrote:

Hornman wrote:

MS wrote:

First 50 mile trip with cool down afterwards. Have driven about another fifty miles. They sound worse. Never heard gears sound so bad. My father in law once drove a dodge pickup from San Antonio to Dallas for me to work on. When I pulled the differential, one of the main cap bolts FELL INTO THE DRAIN PAN. That differential did not make as much noise as mine does.

I don’t have time to mess around getting madder and madder in order to log 500 miles. The old 3.70 is going back in.

If you bought a new Ford with a 9” rear in it and it howled and whined on the way home, would you be willing to “put some miles on it ... it will be fine “?


I’m calling bulls$41+ on your answer, Hornman

You have the right to your opinion. I tend to have more patience than you do. My point was inquiring as to whether you had completed the recommended break in procedure, which you stated you did not. I would probably drive the car 50 miles a day for 10 days, change the oil and reassess. If the gear noise was excessive at that point then I would probably go nuclear on Strange and do my best to guilt them into replacing the gearset.


3/09/2020 2:00 PM  #27

Re: Installing 9” in my 66

When I bought my 66 the rear end howled.  The dealer replaced the pumpkin 4 times.  Still howled.  They finally replaced the housing too.  No more howl.  It lasted over 200k miles.

So, even the factory makes mistakes.

I would do the same thing MS is doing if I still had a howl after 100 miles

Original owner - 351w,T-5, 4whl disks, power R&P

3/09/2020 2:37 PM  #28

Re: Installing 9” in my 66

When you pull the 3rd member out to swap the old one back in the there should be a wear pattern, even after just 50 miles. That should indicate if they are set up correctly. I'd send a pic to Strange letting them know of the noise and what the gears look like. Because if there is a problem you certainly do not want to put another 450 miles on it!


3/09/2020 2:54 PM  #29

Re: Installing 9” in my 66

The drive  AND coast pattern will be an indication of the accuracy of gear cut.
 I always look at the pattern on drive gear as well, it tells a story on how accurate the chunk casting was machined.

Last edited by Rudi (3/09/2020 2:58 PM)

Good work ain't cheap, Cheap work ain't good!   Simple Man

3/11/2020 4:32 PM  #30

Re: Installing 9” in my 66

Sorry to hear the new gears whine.  Sadly I would bet the noise will not go away.  Once the gear set makes noise and they are driven then it's to late to even try to reset the gear pattern.  To me if its as bad as it sounds I would have to say they really screwed up setting the pinion depth.

When do you take the gears out it would be interesting to see what the wear pattern looks like.


3/12/2020 6:12 PM  #31

Re: Installing 9” in my 66

When I received the third member, it still had yellow marking compound on the gears. The patter looked textbook perfect.

After 250 miles of break-in, the noise remains the same.

I spoke with Andrew at Strange and I now believe they will try to fix this issue. He says they have the US Gear stealth series gears that are whisper quiet, but only in 3.70 ratio.  I want 3.50.   So, I am going to put my old aluminum differential with 3.70 back in the car.  I have a used set of Ford original 3.50 gears that could be installed on the aluminum diff before installing it.  Wondering if they could successfully be installed and be quiet???
I will send the new 3.50 Strange setup back to them for replacement with the Stealth gears (which I originally had asked them for, but not available at the time). They could use the 3.70, which I really don’t want, or just ship it in the future after the 3.50 stealth gears are available or, highly unlikely, just refund my money.

Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     Thread Starter

3/13/2020 8:13 AM  #32

Re: Installing 9” in my 66

I bought a set of used ford 3.50 off ebay yrs back. They looked good, but no matter after several attempts, they were whinners.  So yes, if you know there true condition


6/09/2021 6:05 AM  #33

Re: Installing 9” in my 66

What is the axle tube diameter of your rear housing?  I am just starting to get some miles on my car (up to a whopping total of 77 so far!) and the pipes are clunking on the housing when the suspension goes to full compression over bumps and such. I took the over the axle pipes off and am going to bring it back down to the exhaust shop and have them re-bend another set, but my Strange housing has 3" tubes and I am wondering if that is partly contributing to my issue.   If you've got 3" diameter tubes too and no clunking, then the exhaust shop needs to try a little harder the second time around to make it work. 


6/09/2021 8:37 PM  #34

Re: Installing 9” in my 66

3” tubes on mine. Lots of fitting to get 2.5” pipes to not hit.

Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     Thread Starter

6/09/2021 9:48 PM  #35

Re: Installing 9” in my 66

Thanks.  Yeah, the 2.5" pipes don't leave a lot of room, especially with mid-eye springs.  Hopefully they can get it sorted on the next try.


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