DIVERSIFIED MACHINE INC. 2020 PRODUCT GUIDE
Open Tube - Frequently Asked Questions
Q What is the proper oil level for a Bulldog Rear
and how do I fill it?
A The proper oil level varies dependant on
the model. Below is a guide (all capacities
are approximate)
XR-1, XR-2 and XR-3 - 2.5qts.
Baby BullDog - 2qts.
The correct method of filling the rear is
to remove the pinion inspection plug and
the fill level plug located directly below the
inspection plug. On all rears, both plugs are
on the right side bell. Fill the rear until the
fluid runs out the fill level hole. Re-install
the fill level plug and add an additional 4-6
ounces of fluid. Re-install inspection plug.
Both plugs only need to be “snug”. Over-tightening
will cause the plug(s) to stick.
Q What is the best oil for a Bulldog Rear?
A We highly recommend Bulldog Blood (see
page 52) We do not re-package someone
else’s oil. We spent a lot of time and effort
testing different formulations. Our oil is
blended to our proprietary specs. If Bulldog
Blood isn’t for you, we see good, consistent
results from Driven 75w-110.
Q What type of quick change gears will work in a
Bulldog Rear?
A Any 10 spline quick change gear will
work in the standard Bulldogs. Bulldog
recommends only quick change gears
produced from 9310 steel. Inexpensive
gears made using 8620 steel will fail. We
do not recommend using helical cut gears.
Always use gears with the machined
lip facing out. Always install gears the
same way. Never mix gear sets. Sets are
machined as matched units.
Q How do I tell what ratio ring and pinion I have?
A You can call us (717) 397-5347 with the
serial number and we can see what the rear
was built with. If it’s a used rear, we strongly
suggest checking the ratio and not relying
on the build sheet. The easiest way to verify
ring and pinion ratio is to remove the quick
change gears. Install a mark on the tire at
the 12 o’clock position. Install a mark on the
pinion at the 12 o’clock position. Rotate the
tire by hand 1 complete revolution. Count
the pinion rotation as your turning the tire. If
the pinion rotates just over four times, you
have a 4.12. If the pinion rotates almost five
times, you have a 4.86.
Q How often should a ring and pinion be replaced?
A The inspection plug in the right side
bell is placed there for a reason. Weekly
inspection of the pinion should occur. Ring
gears seldom show wear. Rotate the pinion
slowly while inspecting the pinion through
the hole. Look at the drive side of the tooth.
Small pits need to be monitored. Once you
determine the pinion pits are excessive,
replace the ring and pinion. As long as the
unit looks pit-free, there isn’t a life cycle.
Use it!
Q How often should axles be replaced?
A Open tube aluminum axles should be
replaced every 1000 laps.
50 BULLDOGREARS.COM | 717.397.5347 | DIVERSIFIEDRACING.COM