Making switch to after-market hubs not hard

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This article was published 16/11/2007 (6701 days ago), so information in it may no longer be current.

QUESTION — I have an older vehicle, a 1994 Ford Explorer. Over the years we have constantly had problems with the automatic four- wheel drive plastic rings breaking, disabling the four- wheel drive function. I recently was in an after-market parts dealership, which had standard four- wheel drive hubs available at a more reasonable cost than I have paid for second-hand automatic hubs. I am not a mechanic. Is it a simple process to switch to these manual after-market hubs and be able to manually change them on demand, or is there more involved such as transmission differential work, etc?

ANSWER — This is a relatively simple job. An experienced person could probably convert both sides in less than an hour. Allow yourself about three times that (you will likely do it quicker). There are a few special tools you need: a spindle nut socket to turn the nut holding the wheel bearing in place, a 2 3/8 socket to tighten the new spindle lock nut and a torque wrench that will measure 15 inch lbs. torque (NOTE: not ft lbs!) to adjust the wheel bearings correctly. Finally, you will need a small strong magnet or a dental pick to remove the locking pin.

After removing the wheel, the auto hub pulls off. Inside, a ring on the axle shaft similar to a "C" clip and a spacer washer are removed. Now the plastic cam assembly can be pulled out.

A large nut that holds the brake hub and wheel bearings in place. Remove the locking key out of the top spline in the groove first with the magnet or pick or you will damage the spindle and nut. The locking key is a small piece of metal about 8 mm by 15 mm. Now the large nut can be removed.

To install manual locking hubs, a conversion kit is needed. This kit contains new adjusting nuts, locking tab and lock nuts for the wheel bearing assemblies. Install the adjusting nut and tighten firmly while rotating the hub. Back off the nut and then retighten to 15 inch pounds. Install the locking tab and the lock nut. Tighten the lock nut to 150 ft lbs. Adjusting the bearing preload is the trickiest part of the whole procedure. If the bearing is adjusted too tight, it will fail. Too loose and it will wear prematurely, so take your time. Finally, the spacer washer and C clip are reinstalled and the new manual hub goes on.

QUESTION — I currently have an ’06 Toyota Camry five- speed transmission with a V-6 that is rated to pull 2,000 pounds, and it pulls my trailer and boat (about 1,750 pounds) quite nicely. Even though it seems to have enough power there are times when the transmission cannot stay in the lock up and will down shift. From what I gather this is not a good thing so I lock out the overdrive and go in fourth gear so as to not overheat the transmission.

Every time I’m looking for a car that can tow something, they all tell me to get a truck or van. Problem is, I don’t want a truck or van, I want a car. I only have one vehicle and probably 90 per cent of the time it’s used as a car and 10 per cent of the time I want a car that can tow. Now for the question. Is there any way I can get a temperature gauge installed that will tell me the temperature in the transmission? And if so, what are the temperatures I should be looking at so not to do any damage?

ANSWER — Most ATF can withstand normal operating temperatures of around 200 degrees F for tens of thousands of miles. However, if the temperature of the fluid rises above 220 degrees F the fluid starts to break down quickly. Above 300 degrees, fluid life is measured in hundreds, not thousands of miles.

Installing a transmission temperature sending unit in the return line from the transmission oil cooler to the transmission and connecting it to a gauge inside the car is the easiest method of monitoring the oil temperature. Many of these gauges say to install the sender in the pan, but you can install a T fitting in the return line to install the sender unit. Look for gauges at truck accessory stores, as trucks are more commonly used for towing.

To keep transmission oil temperatures down, use light throttle acceleration and shift to lower gears in the transmission when towing or climbing hills with a load. The torque converter generates most of the heat inside a transmission. If transmission temperatures start to climb, back off the throttle, reducing the slip in the converter.

Jim Kerr is an experienced mechanic, instructor of automotive technology and member of the Automobile Journalists’ Association of Canada. You can e-mail questions to Jim at the address below.

kerr.jim@sasktel.net