NP208 Slip Yoke Eliminator Kit

NP 208 SYE

Do not confuse ours with other kits here you are required to drill & tap the output shaft on the transfer case. Because of the surface hardness on the main-shaft, this can be very difficult to do. Beyond that, the “kits” others offer, do not shorten the output shaft, you merely bolt on a new yoke with no significant lengthening of the drive shaft.

With our SYE kit, we take a stock output shaft and precision machine output shaft so that it is shorter. Then we take the speedometer housing -that also serves as the bearing & seal retainer and shorten it, along with machining in a new seal bore. The new seal will then be installed When finished, the rear output on transfer case will be a flange that is firmly ‘sandwiched’ between the rear output bearing and the output flange.

The price for the SYE kit is $400.00.

Because this kit uses a modified stock output shaft, we do require a core charge. The core charge is $400. The core required is for the stock speedometer housing and main-shaft. To receive full core credit, original main-shaft and tail cone housing must be returned in good condition. Parts will be inspected prior to any core credit issued. Bent main shafts will not be accepted for core refund. Return freight will be at customers expense

If you would like to avoid the core charge, you can send your core parts to us in advance.

Prices for the SYE kit and drive shaft package, complete with the double cardan drive shaft will begin at $620.00 and go up to $880.00. Much of the pricing will depend on the length of the drive shaft required & the size of the universal joints needed in the drive shaft.

If you would like to plan on having your drive shaft delivered at the same time as your SYE kit, we can easily do this for you. We would only need a few reference measurements. One is for the for the length, as shown below. This measurement is from the end of the output shaft on the transfer case to the face of the pinion yoke at the differential end (which would be the same as the centerline of the universal joint at this end). The length measurement should be taken with the suspension normally loaded (static ride height). Your tape measure should also follow the approximate slope of the drive shaft, going straight from point to point (no bend in the tape measure) and it should be done at about the 3 or 9 O’clock positions at each end (center height).

Depending on the application, we may also need to know the universal joint size at the differential end. If you do not know which series of universal joint size you need, you can determine this using the art below and measuring for either the E or F dimensions and the D dimension.

Please note that in the art above, it represents two different type of yokes/joints. On the left is a Spicer type yoke, which has centering lugs to center the universal joint in the yoke. On the right, it represents Saginaw & Detroit type yokes. On the Saginaw/Detroit type yokes, the inside surface of the yoke ears are machined flat so that snap rings -which install into a grove in the circumference of the bearing cap- center the universal joint. The Saginaw yoke is common to many GM applications, while the Detroit type yoke would be exclusive to Mopar applications.

Some common Universal joint sizes and their corresponding reference measurements are as follows:

SPICER YOKE/JOINT

SAGINAW/DETROIT YOKE/JOINT

 

Spicer

1310

D=1.0625" (1-1/16")
E= 3.218" (3-7/32" which is roughly 3-1/4")

1330

D= 1.0625" (1-1/16")
E= 3.625" (3-5/8")

1330L

D= 1.125" (1-1/8")
E= 3-5/8" (The oversized cap -D dimension- is used on some Ford applications and would be as it attaches to the pinion yoke only. The other bearing caps would be 1-1/16")

1350

D= 1.188" (1-3/16")
E= 3.625" (3-5/8")

1410

D= 1.188" (1-3/16")
E= 4.188" (4-3/16")

Detroit

7260

D= 1.78" (slightly greater than 1-1/16") 
F= 2.125" (2-1/8")

7290

D= 1.125" (1-1/8")  F= 2.625" (2-5/8")

Saginaw

3R

D= 1.125" (1-1/8")  F= 2.562" (2-9/16")

 

After the installation of a SYE kit, you will then have a drive shaft that is longer than stock which will reduce joint angles and the ability to use a Constant Velocity (CV) double cardan type drive shaft. This will reduce drive shaft vibrations for smoother operation and a longer life on the related components. With this conversion you should be able to keep the transfer case at stock height. You will however, want to be sure to pitch the differential so the pinion points more or less directly at the output of the transfer case, maintaining a minimal joint angle at the differential end. For example; if the slope of the drive shaft is 15° the pinion should be between 12° and 15°. With 13° or 14° being ideal. Again, this is just an example and your actual numbers will probably be different.

 

For a simple method of determining these slopes/angles, please refer to this link for a simple method, using very simple tools.

If you have questions, or would like to place an order, please contact us.