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This page may contain common questions that are often asked by DTS customers and sales reps.

View Setup Specs

Q. What do I need to know to help with my order? 
A. a. Year, make, and model of vehicle. 
b. How many cover bolts? 
c. What is the ring gear diameter? 
d. How many spline on the pinion? 
e. How many axle spline? 
f. What does the cover look like? (physical appearance)
Q. How can I figure out the ratio of my particular rear end? 
A. a. Look for any tags or stampings in your housing. 
b. Count how many teeth are on the ring gear, as well as the pinion gear, then divide the number of ring gear teeth by the number of pinion gear teeth. 
c. Obtain any numbers off of your ring gear and pinion gear. We may be able to cross-reference them.
Q. What if I have a Dana rear end or front end?
A. The best solution to help us determine what parts are required when using Dana would be to obtain the B.O.M. number. 

Q. What is the B.O.M. number?
A. B.O.M. is for "Bill of Materials" which represents the parts used to build specific rear ends. Made by Dana.  Please see ExampleA. Check your parts and application on the net at
Q. What is posi and/or limited slip?
A. Posi and limited slip are the same. This occurs when both tires under a specific load are turning equally, yet when under an uneven load - one is allowed to turn at a different speed, which allows better traction, as well as comfort. They are two different words to describe an item; example: motor or engine. 

Q. How can I determine what ratio to use for my application?

mph x gear ratio x trans ratio x 336 ÷ Tire Diameter = RPM 
Tire Diameter

70 mph x 3.73 (gear ratio) x .67 (trans ratio) x 336 ÷ 27(tire diameter)   = 2176RPM 

70 mph with a 3.73 ring and pinion over drive transmission in 4th gear with a 27" tire will perform at 2176 RPM


Q. How can I tell the difference between a GM 8.2 10 bolt, Buick/ Olds/Pontiac 8.2 10 bolt, and a GM 8.5 10 bolt?
A. Each of these has a different spline. 
GM 8.2 = 25 spline shaft 
Buick/Olds/Pontiac 8.2 = 27 spline shaft 
GM 8.5 = 30 spline shaft 
Q. What is the difference between a Pro Gear and a Street Gear?

A street gear is designed for daily driving. Long distances and extreme heat are not a problem for these gear sets.  For this reason, these are also the gears of choice for oval track racing.

A pro gear is strictly for drag racing. In a situation where there is excessive torque, a street gear is not designed for this application, and a pro gear should be used. Pro gears are much softer than street gears, in which the teeth actually bend instead of snapping off, allowing a run to be completed. 

Q. What is the proper way to measure a driveshaft?
A. Take your slip yoke for the transmission or transfer case and push it all the way in, then pull it out 3/4 to 1". This allows for normal riding position. Measure the driveshaft from the center of the u-joint cap to center of the u-joint cap at ride height. 
Q. Does DTS offer installation?
A. Yes, we install parts. We have a full service department with four      hoists and several qualified technicians. You may also ship your differentials to us to have labor performed. 
Q. What is the proper backlash for my ring & pinion?
A. For light duty vehicles, (1 ton or less for street use), backlash is .007 to .010 (7 to 10 1000ths of an inch). For pro gears, backlash is .006 to .008 (6 to 8 1000ths of an inch). 
Q. Is there any way to determine what gear ratio I have if the tag is gone and I don't want to remove the inspection cover?
A. Draw a straight line on your driveshaft. If you have a posi or locking differential you must rotate any tire completely 1 revolution and count the number of revolutions on the driveshaft. If you have an open or non-locking differential, you must rotate the tire 2 revolutions. This may not tell you exactly what ratio you have, but it will be reasonably close.
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