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Experience Using Doctor Diff "Sure-Trac II?"

piver

piver

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Hi All - Heard in forums here about a Doctor Diff (DoctorDiff Drivetrain Components). He carries an 8 3/4" Helical Gear Sure-Grip called "Sure-Trac II" - does anyone have experience using it? I'd like to know how you rate it. Would go with Eaton's Detroit Truetrac, but DocDiff says his Sure-Trac is superior. Need to hear from someone who's actually used it. This is for my '68 Coronet R/T (didn't come with the Sure-Grip option). Thanks!
 
I'm in for the knowledge. I have Eaton True Tracs in 2 cars and haven't had any issues to date. The 440 is putting out around 500hp at the crank.
 
I installed one last Spring (2022). He was great to work with. I put in the sure grip ii, a new case, axles and green bearings all from drdiff. He set up everything and I installed it. I had a little bit of a decelleration coasting whine from about 70 to 40 going down hills for the first 50 miles or so but it is gone. Everything I've read said it is a normal break in. It is a cruiser so I've not really hit it (other than the kickdown now and then), but it has been trouble free for over a year. I made a post over a year ago about rear end play and clunking, and everyone that responded to the post said to refurb the 3rd member. I did the u-joints first and no change. So I got something plug and play. It's been great but I can not compare it to anything else except the clunky diff I replaced. YMMV...
 
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Pics before the install...

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I have one in my '67 Coronet and have no complaints at all. The unit is very consistent in application of torque to both tires with no squirreliness that you sometimes get with a locker. It is very predictable. The unit is smooth and quiet as well. Bottom line is, it just works. As far as the experience with Cass goes, things couldn't have gone any smoother. He has a wealth of knowledge and it shows when you are ordering. You will get what you need, it will be done right, the price will be fair, and you will know where everything stands the entire way through.
 
You won't find me in the Dr. Diff nut swinger crowd. Spent a good amount of money with him and then bought a pair of spring hangers which were incorrect for the car. His response: the finger.
 
mrmolding said:
I installed one last Spring (2022). He was great to work with. I put in the sure grip ii, a new case, axles and green bearings all from drdiff. He set up everything and I installed it. I had a little bit of a decelleration coasting whine from about 70 to 40 going down hills for the first 50 miles or so but it is gone. Everything I've read said it is a normal break in. It is a cruiser so I've not really hit it (other than the kickdown now and then), but it has been trouble free for over a year. I made a post over a year ago about rear end play and clunking, and everyone that responded to the post said to refurb the 3rd member. I did the u-joints first and no change. So I got something plug and play. It's been great but I can not compare it to anything else except the clunky diff I replaced. YMMV...
Click to expand...
Perfect @mrmolding! Thanks so much for sharing your experience running the "Sure-Trac II" from Doctor Diff.
 
Brewzer67 said:
I have one in my '67 Coronet and have no complaints at all. The unit is very consistent in application of torque to both tires with no squirreliness that you sometimes get with a locker. It is very predictable. The unit is smooth and quiet as well. Bottom line is, it just works. As far as the experience with Cass goes, things couldn't have gone any smoother. He has a wealth of knowledge and it shows when you are ordering. You will get what you need, it will be done right, the price will be fair, and you will know where everything stands the entire way through.
Click to expand...
Perfect - thanks so much @Brewzer67!
 
piver said:
Thanks @Frank Mopar. How long have you been running your Sure-Trac II? Any engine and gear info etc. that runs with it would be helpful too.
Click to expand...
Two years running. 360, cam, header, rpm manifold and 456 gears.

As stated its smooth on the street. No chatter turning corners and lights em both up when needed.
 
piver said:
@Speedbird When will you start running with that Sure-Trac II?
Click to expand...
Doctor Diff is like other specialty suppliers . People that know there stuff and sell good products.
Brewer's is like that. They have no problem talking to customers prior to ordering to be sure people get what they need. No body knows everything.
Like I told Mancini one time in ordering.
"I know what I'm doing. I've just never done this before."
Then they were very helpful.
You pay your money and make the best decision based on that.
 
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