Denny's Driveshafts Frequently Asked Questions
Here is a small collection of frequently asked questions about driveshafts and driveline related items. Look over the list and hopefully it will help you with your problem. Unfortunately we cannot address every question here on this page and there may still be some unanswered questions that you may have. If you have something that is not answered her please see our Contact Us Page and fill our the form with your info. We will answer as soon as possible.
Frequently Asked Questions
Angle
How much driveline angle is right for my application?
Diesel Pick Up Trucks
What is available for my Diesel pick up truck?
FAQ
How much slip travel should I have?
Why does the rear u-joint fits loosly in the pinion yoke?
How tight should I tighten my u-bolts?
Why does my rear u-joint wear out so often?
Can I order a driveshaft without a transmission slip yoke?
Can I order a driveshaft without u-joints?
Can I send my factory driveshaft in for repair or balance?
Why did my driveshaft tubing twist or break?
My driveshaft is too short. Can I put on a longer slip yoke to make it fit better?
My driveshaft is too short. Can you add a little tubing to it to make it longer?
Import Driveshafts & Driveline Parts
Do you offer driveshafts or driveline parts for Import cars and trucks?
Maintenance
How often should I add grease to my non greaseable u-joints?
How often should I grease my greaseable u-joints?
Measuring Questions
Do I have to measure to order a driveshaft?
Can I send in my driveshaft so you can use it for a template?
How much of a mistake am I allowed in my measurements?
I want to order a driveshaft but my car is all apart?
Payment
What forms of payment do you accept?
Series
What is the difference between 1310, 1330 and 1350 Series?
When is it necessary to upgrade to 1350 series?
What is the difference between the Chrysler 7260 and 7290 series?
What is the stock General Motors u-joint called?
Troubleshooting
Why do I continue to break u-joints?
My transmission slip yoke feels like it is binding inside my transmission?
Answers to Frequently Asked Questions
Angle
How much driveline angle is right for my application?
Thats a loaded question. The best answer is....the least amount of driveline or u-joint angle is the best amount of angle. Try to achieve the least amount of u-joint angle but don't make it less than 1 degree. A little known fact about u-joints is that they require about 1 degree of operating angle to get the needle bearings rotating. If they do not rotate they will fail. Too much angle will also cause them to fail. The type of rear suspension also plays a big part in setting the angles as well as the engine/transmission angle. Leaf spring cars have a need for more downward pinion angle due to spring wrap-up while coil spring cars control the situation better. Hard acceleration as in the case of a drag race car requires a different setting than a street driven car. Traction bars, ladder bars, 4 links, independent rears all have special needs and requirements.
Diesel Pick Up Trucks
What is available for my Diesel pick up truck?
At this time we do not offer driveshafts in the 1410 series for diesel pick up trucks. We do, however, offer Spicer universal joints to replace your originals. Diesel pick up trucks whether 2wd or 4wd require a minimum of 1410 series to handle the horsepower and torque output of todays high performance diesels. We will offer 1410 series in the future but at this time we do not.
FAQ
How much slip travel should I have?
In most applications the minimum is 3/4 inch and more than 1 inch is not necessary. This is measured with the rear suspension supported on safety stands or with the rear end on the ground.
Why does the rear u-joint fits loosly in the pinion yoke?
A common mistake that is made when measuring is to measure the rear u-joint caps instead of measuring the pinion yoke. This is most common on Ford rear ends where a 1 1/8 inch cap diameter is found at the yoke saddles. Unfortunately someone has installed a u-joint with 1 1/16 inch caps. Always measure the pinion yoke.
How tight should I tighten my u-bolts?
1310 series and 1330 series should be tightened to 17 ft/lbs and 1350 series to 20 ft/lbs. You should never tighten the nuts on any u-bolt excessively. This will cause the cap to distort and the u-joint will fail prematurely.
Why does my rear u-joint wear out so often?
This is usually the case when a u-bolt style pinion yoke is used. The pinion yoke is not the problem the overtightening of the u-bolt is the cause of the failure. You may find that every time you change the damaged rear u-joint you will find that one or both of the journals or caps that are under the u-bolts are destroyed and the ones that are pressed into the shaft are still in good shape. You did it to yourself! 17 ft/lbs for 1310 & 1330 series and 20 ft/lbs on the 1350 series. Click to see Photo
Can I order a driveshaft without a transmission slip yoke?
Yes. We will need your slip yoke to balance your driveshaft correctly.
Can I order a driveshaft without u-joints?
No. We cannot build a driveshaft without u-joints.
Can I send my factory driveshaft in for repair or balance?
Yes. We offer repair service for alterations, balancing or diagnosis purposes. Please call to have an order written so that we know what to do with your driveshaft when it arrives.
Why did my driveshaft tubing twist or break?
There are many reasons. If you are using a stock driveshaft in a racing application then you already know the answer. Stock shafts should never be used for racing. If you had a driveshaft built by a driveline shop and it has broken or twisted the tubing then you should take it back to where you bought it. They apparently built your driveshaft with tubing that was similar to stock driveline tubing or possibly selected a tube diameter or thickness that was not correct for your application. Just because the shop builds dump truck shafts does not mean it can handle the requirements of a race car.
My driveshaft is too short. Can I put on a longer slip yoke to make it fit better?
This is a common problem and many times this seems like an inexpensive way to make it fit better but this type of fix should be avoided. We never recommend installing a longer slip yoke when the shaft is actually too short for the application. Some transmission slip yokes are available with a longer barrel but they were designed longer for a specific application and not for the purpose of extending a shaft. Using one on a driveshaft that is actually too short for the application can lead to vibration and output shaft bushing failure. In extreme cases the internal spline can twist and bind up the slip movement. Don't do it!
My driveshaft is too short. Can you add a little tubing to it to make it longer?
No. The correct way to lengthen a driveshaft is to remove both weld yokes and install a new tube of the proper length.
Import Driveshafts & Driveline Parts
Do you offer driveshafts or driveline parts for Import cars and trucks?
At this time we do not offer driveshafts or driveline parts for Imports. We may, however, offer them at a later date. When we do it will be posted on our home page.
Maintenance
How often should I add grease to my non greaseable u-joints?
Never! Just leave them alone and they will last for a very long time. You can do more harm than good by taking them apart.
How often should I grease my greaseable u-joints?
Greaseable u-joints should be greased every 3000 miles or possibly more often. You cannot over grease a greaseable u-joint.
Measuring Questions
Do I have to measure to order a driveshaft?
YES! We want your order to fit correctly. Measuring is the only way we can be sure your driveshaft will fit and perform perfectly for you. We have provided the best measuring diagrams in the business so that you can easily get the right dimensions
Can I send in my driveshaft so you can use it for a template?
Yes you can. As long as you are 100 percent sure it fits correctly. Please let us know if you want it returned.
How much of a mistake am I allowed in my measurements?
NONE!!! Its too easy to get it right so why do it wrong. Never use the hook on the end of a tape measure to measure a u-joint. It is best done with a good steel machinists ruler or a dial caliper but if those tools are not available any good ruler will do as long as it reads down to 1/16 of an inch. Use the tape measure hook for the overall length only!
I want to order a driveshaft but my car is all apart?
Unfortunately it will be best for you to wait until you have it back together to measure correctly.
Payment
What forms of payment do you accept?
We accept MasterCard and Visa credit cards.
We also accept US Postal Money Orders.
Series
What is the difference between 1310, 1330 and 1350 Series?
The "series" of a driveshaft or universal joint is determined by the actual dimensions of the u-joint. While the front and rear u-joint can be of two different sizes the shaft is only as strong as the smaller one. The 1310 series u-joint measures approximately 3 1/4 inches wide. The 1330 and 1350 both measure approximately 3 5/8 wide. The 1310 and 1330 series can have cap diameters of 1 1/16 and/or 1 1/8 inch or a combination of both sizes. The 1350 series has a cap diameter of 1 3/16 inch and the body and journals are bigger than the 1310 or 1330. Remember 1350 is almost never found in production car driveshafts.
When is it necessary to upgrade to 1350 series?
It is always a good choice to upgrade to the 1350 series components whenever your application is used for racing or with high horsepower and street use. Stock driveshafts were designed to handle a modest amount of horsepower. If your application has more than 400 horsepower then its time to consider a new shaft.
What is the difference between the Chrysler 7260 and 7290 series?
The 7260 and 7290 series are the two sizes that are commonly found on Chrysler products. They represent the two stock sizes that have been used for many years. The 7260 series is the “small” Chrysler u-joint size and the 7290 series is the “big” Chrysler u-joint size. The 7260 series is similar in size to the 1310 series and the 7290 is similar in size to the 1330 series. They both utilize the inside “C” clip design to hold the u-joint within the yoke whereas the 1310 and 1330 use the outside snap ring design.
What is the stock General Motors u-joint called?
General Motors typical u-joint size found on most passenger cars and light trucks is commonly know by a few names. They may be referred to as “3R” or “S44” or “Saginaw” but they are all one in the same. Depending on who is doing the talking you may hear any one of these terms. The factory original u-joints are held into the yokes by injected plastic. This u-joint is similar in size to the 1330 series. The replacement u-joints utilize the inside “C” clip design to hold the u-joint within the yoke whereas the 1330 series uses the outside snap ring design. You should be extremely careful not to heat the plastic with a torch to remove the original u-joints because the heated plastic will emit toxic fumes that are not good for your health.
Troubleshooting
I have had my driveshaft back to the shop that built it many times and it still vibrates. Can you fix it?
The answer is Yes and No. Many times our high speed balance equipment can make a big difference but in some cases nothing will make it run better. We can determine that and let you know what your options are.
Why do I continue to break u-joints?
The answer can be that the u-joint series is too small for the application. Or possibly you are using an inexpensive parts store u-joint that does not offer strength. Maybe you are using a greaseable u-joint and it is breaking across the grease fitting hole. The corresponding yoke is damaged or distorted and causing premature failure.
My transmission slip yoke feels like it is binding inside my transmission?
The problem may be that the internal splines of the slip yoke barrel have a slight twist and the slip yoke needs to be replaced. This problem may be the result of too much horsepower for the slip yoke design and or material. A manual transmission or an automatic with a trans brake can cause this damage because of the forces applied to the splines during a starting line launch. If you look inside the slip yoke you will see a slight twist to the spline. This twist is usually at a point that corresponds with the end of the transmission output shaft. As you insert the slip yoke into the transmission it will bind when it reaches the twisted area. Click to see photo.
