William Lane demonstrates how to flip the shifter on a TREMEC TKO 5-Speed or a TREMEC Magnum 6-Speed for Jeff Kauffman.

 

What affects the gearing of a 4WD?

Gearing is all about getting the power from the engine to the ground. The simplest example is your old 10 speed bicycle. In the lowest gear, you could climb hills while making the most of your effort. On flat land, however, this lower gear would waste your effort because the higher gear can go further with each push of the pedal.

A 4WD vehicle is more complex, with the power from the engine transferring through several different parts. The components that will affect your 4WD’s gearing are: the transmission, transfer case, differentials, and tire diameter. You can greatly improve your vehicle’s performance by understanding how all these parts work together.

What should I consider first?

With gearing, there are no absolutes, no right or wrong answers. You can gear your 4WD so that it crawls over the greatest obstacles with ease but is so bad on the interstate you have to haul it. Or, you can gear your 4WD so that it gets amazing gas mileage and flies down the interstate, but it can barely hop a curb. Most people would want their vehicle geared somewhere in-between these two extremes. That said, the first thing you should consider is how you want to use your 4WD. You can then play with the numbers until you find your sweet spot.

What is a crawl ratio?

The crawl ratio is the ratio of torque at the wheels to the engine flywheel torque. A crawl ratio gives you an idea, but not a complete picture of how your 4WD will perform under different circumstances. The higher the crawl ratio, the more control you’ll have to go slowly (crawl) over obstacles. A lower crawl ratio will be great for daily driving. Like most things, you can have too much of a good thing. A good scale to go by is:

• Under 50 Crawl Ratio - Most factor

Sometimes in transit, the TKO's synchronizers will shift and become lodged, locking up the input shaft. Ben DeHaven is here to tell you how to easily correct this condition.

 

Mating the transmission and bellhousing can sometimes be a difficult task because you don't have much wiggle room and transmissions are heavy. There are a few tricks, you can put in the slip yoke and twist it back and forth to get the input shaft lined up correctly. You can gently jiggle the transmission to get it past whatever is hanging it up, but you can not, and it's in ALL CAPS, BOLD AND UNDERLINED in the installation manual, use the bellhousing bolts to draw the transmission to the bellhousing. As our installation manual says, this will result in broken ears and will void the warranty.

Recently, one of our customers learned the hard way that this warning is printed in every manual for a reason. While he managed to draw the transmission to the bellhousing using the bolts without breaking the ears, this put the transmission into a bind. Later, when he drove the car, the rotation of the engine increased the pressue of the bind to the point that something had to give and the aluminum transmission case lost its ears.

Let his misfortune be your warning, never draw in a transmission with the bellhousing bolts!

Our customers often call us about vibrations, so we thought we’d make a check list of items to help you nail down a vibration in your car or truck.

 

The bellhousing isn’t dialed in correctly or at all.

 

__ Did you neglect to dial-in your bellhousing?

 

If you haven’t dialed-in your bellhousing, don’t even go on a test run. First, failing to dial-in the bellhousing will void your warranty. Second, you’re at risk of not just a few vibrations, but you could cause severe damage to your transmission. If it’s too late, you’ve already driven the car without dialing it in and you now have a vibration, check it. Even if it’s not the bellhousing, you can rest easy knowing you’re not destroying your transmission.

 

The vibration is felt through the steering wheel.

 

__ Do you feel the vibration the whole time you’re driving?

 

The culprit is most likely your tires or wheels. If your tires are in good shape and inflated properly, the wheels can be damaged or be out of balance. Even a small bump or pothole could have damaged your wheel and it’s relatively cheap to get them checked.

 

__ Does the vibration occur mostly at speeds under 30 mph?

 

This is almost always a tire or wheel problem. A tire with a bad belt, tread separation, or flat spots from sitting too long can go out of round and cause vibrations. A damaged, out of round wheel will also vibrate more at this speed. Also, make certain the wheel is properly tightened to the hub.

 

__ Does the vibration only occur in the 55-60 mph range?

 

Most likely, the tires are out of balance. It could also be a missing wheel weight or something stuck to the wheels causing the wheels to be out of balance.

 

__ Does the vibration only happen when you apply the brakes?

 

It is most likely th