Rear end upgrade

[mrose]

Hi Guys
I have an 8.25 rear end in my Barracuda, running a 340 with 727 tranny. The rear gears are 3.55's, but the rear end is open. I would like to change it to a sure grip.
Can that be done? if so do I have to change the gears or can I stay with the 3.55's that are in there now?
my rear end casting number is #2852905.
It also seems I can change to a 3.90 by just changing the pinion gear as the ring remains the same at 39 teeth and the pinion goes to 10 instead of the 11 that is on their now.
Am I correct in all these assumptions?
If I can just change and go to a sure grip is that something I can tackle or is it best to take it to a rear end shop?
Thanks in advance for the information, this site is awesome and everyone is always willing to give advice.

 

[mguner]

I put a Dakota gear set and carrier in my 75 Dart. You need to know your axle spline count. You may have some carrier bearing issues as well but as long as you don't pull the pinion the issues should be minor. Setting the back lash and pre load is the only thing you will need to do. There are a couple of different size carrier bearings so you need to know what you have and what you are getting. If you get a carrier that already has the right bearings and races it's a big win. You cannot mix rings and pinions though. Seems like pre 97 Dakota 27 spline was the magic number for my 75.

 

[mrose]

Thanks Mgunner, and yes it is a 27 spline count.

 

[rumblefish360]

Free shipping @ Summit; http://www.summitracing.com/parts/aub-542072

$200 Cheaper @ http://www.doctordiff.com/8-1-4-spicer-trac-lok-differential.html

 

[mrose]

Thank You Rob, Good information.
I see the one from Summit is Auborn, Does Dr. Diff make their own?
If so is the quality different?
Thanks Again

 

[racerdan80]

Got my trac loc (clutch style) from Dr Diff for my 8.25 no issues, good unit

 

[mrose]

Racer Dan,
Did you install it yourself?
I was told there was modification that need done?
Thanks in advance

 

[rumblefish360]

I'm sorry, I do not know. Get all the info you can about the diff. from Summit and the Call Dr.Diff. To see if there is a difference

 

[alpha13]

Ring and opinions go together. They mate to eachother so you can't swap just a the ring. You can search on eBay for a suregrip. I got mine from a guy 100 miles from me for 300 bucks for a set of 3.55s and the carrier with good clutches. Paid the shop 300 dollars to hot tank my rear end put it all back together with new bearings. I thought it was a pretty good deal. The shop said the gears looked pretty good so I wouldn't have a problem with them for a long time. I had don't remember how many splines my axles were right off hand but I got the same carrier and everything went together fine. Works great, and I beat the **** out of that rear end. It's great. Lol I guess if it breaks I can go to 4.11 gears.

 

[jbc426]

...Hi Guys
It also seems I can change to a 3.90 by just changing the pinion gear as the ring remains the same at 39 teeth and the pinion goes to 10 instead of the 11 that is on their now.
Am I correct in all these assumptions?...
QUOTE]

It doesn't work that way. The pinions and ring gears are different shapes, but have the same tooth count. Might be better off buying a good used unit with the gears you want.

 

[halifaxhops]

Another doner is a dana 35, found in the late 90's grand Cherokee's and most are track locks.

 

[SGBARRACUDA]

I do have a good 8 1/4 sure grip unit I would sell but it is complete with a set of 3.55 gears which won't help you as you already have this ratio.

 

[racerdan80]

Didn't install myself, done at a drivetrain shop in Tulsa , OK. Pretty straight forward thou as I was only charged 150.00 If anything extra was required I would have been charged. The oem limited slip is a good unit for street use, goes smoothly around corners and hard off the line can feel both tires hook up.

 

[racerdan80]

The only thing I have read wheee a modification was required was some clearancing for install an auburn differential. The oem trac loc style was just a drop in