December 2009 4x4 Truck Repair Questions - TechlinePosted in How To: Tech Qa on December 1, 2009
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Twisted Toyota Drivetrain Needs Rx
Question: I have a '79 Toyota with 5.89:1 gears. I just twisted the rear end up and down, the perches bent the tube, and now I don't know what to do. Please help. I also blew the trans, so I am in a big bind. This is taking a toll on me and my wife. This is my pride truck and I have been having so many problems that are putting me behind schedule. This truck is for us to go out and spend some fun time together.
Church Point, LA
Answer: First, I am not quite sure what you mean by "twisted the rear end up and down." I don't know what to say about your problem other than be nicer to your truck. Toyota transmissions and rearends are pretty stout-in fact, they're overkill for the power that the engine produces. The question is, why did the rearend bend and why did the transmission break?
What kind of answer are you looking for? Seems to me the only solution is to replace the rear axle housing and have the transmission rebuilt or exchange it for a rebuilt one. Most important of all-figure out why this happened and make some corrections, perhaps mechanically or in your driving style so that it doesn't happen again.
I am going to make a wild guess that because you're running 5.89:1 gears you are also running a tire much larger than 35 inches. Larger tires put a major load on the drivetrain and a lot of leverage on the axlehousings. Keep in mind that the truck most likely originally came with a tire in the 29-inch height range. Could it be that your rear springs are a bit worn out and thus letting the axle hop up and down under certain driving conditions? This is also a quick way to break gears and axleshafts, besides bending the housing. If this is the problem, then you need to correct it before proceeding any further with modifications.
Mystery Grand Cherokee Taillight Covers
Question: On your "Ain't It Grand-er" Grand Cherokee project, what type of taillight covers were those on your Jeep? The silver taillights that were almost metal looking? I only saw them in Part 1 of your buildup series, and I tried to zoom in on the picture, but it was distorted and I was unable to see what they were. I love them!
Answer: Wow, that was a long time ago. We actually had several items on the Grand besides the taillight covers that were from EGR (866/749-2610, www.gotoEGR.com). While they were made of plastic, they were made to look like they were constructed of carbon-fiber. We are still using the fender flares, as well as the hood, rear, and side-window air deflectors. However, the taillight covers did not allow sufficient light to shine through to make them safe or even legal. That "carbon-fiber look" is no longer available-only smoke color in the hood and rear air deflectors.
Wants Lower Cruising Gear for F-350 Tow Rig
Question: I have a 2003 Ford F-350 with the 7.3L Power Stroke and an automatic in it. I love the truck, and 90 percent of the time, I pull a heavy trailer. When I am on the road, with or without the trailer, I dare not to go much over 70 mph, at which point the tach is around 2,500 rpm. I know the truck is geared low to make it a better pulling truck. I do not want to change the gears in it, but would like to drop the rpm when I am moving down the interstate. Is there some kind of transmission splitter or extra gearing I can add to the transmission to get an extra gear on top of the current ratios?
Iowa Falls, IA
Answer: Not a problem at all. What you need is an additional overdrive unit that will bolt on behind the transfer case. This is the preferred way to do it as you only need one adapter and only have to shorten one driveshaft. Or, if you wanted to use it in four-wheel drive, there is a unit that bolts between the trans and transfer case, which is quite a bit more expensive since it requires two adapters, both driveshafts being modified, and it requires the transfer-case crossmember to be relocated.
Gear Vendors (800/999-9555, www.gearvendors.com) has a great unit that is well up to handling just about any load you can put behind it. You can also shift it under a load in any gear. It's a very quality product, and the price reflects it at about $3,200.
Wants Flipped Tie-Rod Tips
Question: I am currently building up a 1985 CJ-7 for mild off-roading. My dad was telling me to find a part for the tie-rods he had seen. It was some kind of adapter to flip the tie-rod to mount on top of the knuckle, instead of underneath, to reduce the angle of the rod. He said he's seen it in the 4 Wheel Parts catalog, but it is not in there anymore. Have you heard of any thing like this?
Answer: There are a couple of ways to go about this. I was faced with this same problem lots of years ago. Here is how I solved it.
Luckily, I have a lathe, so I was able to build the parts I needed. But in reality, some local machinist could make the part for you. First thing I did was determine how big of a hole I could drill in the steering knuckle arm, without causing any additional strength loss, that was slightly bigger than the widest end of the original taper. Then I located a piece of DOM heavy-wall tubing that was larger than the new hole size in diameter and turned down the outside so it was a thousandth of an inch (or so) bigger to cause an interference fit when installed as a bushing. Then I figured out the taper on the tie-rod end I had chosen to use, and machined the inside of the bushing to this taper. It was then just a simple matter of heating up the end of the steering arm, freezing the bushing, and then driving it into place so that the taper was now at the top.
Ok, that took a bit of time and machine work. Want the easy version of it? Go to OK 4WD and Tire's Website (www.ok4wd.com), and in the search box type in "flip kit." They do a slightly different approach that arrives at the solution with a lot less work. They offer some special sleeves and a reamer for, like, 90 bucks that make it a whole lot easier and faster than what I did.
Transmission Swap for FJ-40 Cruiser
Question: I have a 1977 FJ-40 with a 5.7L 1993 Chevy 350 TBI V-8 in it. I am having a shop install a 700R4 tranny at present. (It has the stock four-speed in it now.) I am going to retain the stock transfer case. He tells me (the shop) because of the longer tranny and adapters (from Advance Adapters) that the driveshaft is only going to be ten inches long. Is this short of a driveshaft alright? He tells me not to worry, that it will be fine. But then he tells me I'm lucky I am not someone who takes it on the Rubicon (something about wheel travel).
I also would like to put a CV driveshaft back in it, which it has now because it took away the vibration I had at one time with out it. He says I won't have to worry about vibration with this short of a driveshaft. Am I making a mistake having this transmission installed?
Answer: Yep, ten inches is pretty darn short for a driveshaft, especially one with standard U-joints in each end. I suggest that you have the shop that is doing the trans swap get a hold of one of the better driveline shops and have a shaft capable of working at high angles built. I know for a fact that J.E. Reel (www.reeldriveline.com) or Tom Wood's (www.4xshaft.com) can supply you with what you need.
You want to make sure that when the suspension completely droops, that neither end of the shaft binds the U-joint into the yokes. Check this out by lifting the rear of the Jeep completely off the ground and then manually turn the driveshaft by hand to check for any binding (also make sure you have safely blocked the front wheels in both directions and the vehicle is supported by jackstands before crawling under it). You may have to make up a nylon limiting strap between the frame's crossmember and the center of the axle to keep if from dropping too far down. If you should go with a CV-joint at the transfer-case end, you need to rotate the rearend upward so that the pinion is pointing directly in line with the shaft, or perhaps two degrees or so downward if you're using fairly soft springs.
Oh, and yes, you always have to worry about driveline vibrations as they can quickly destroy U-joints, and even damage bearings in both the rearend and transfer case.
Letter Of The Month
Caprice To CJ Steering Swap?
Question: I have a 1979 CJ-7 that I have been working on and need some technical assistance. I installed a power steering box from another Jeep and have adjusted it as much as possible, but there is still too much play in the steering (old and worn out).
I also have the problem that I have a small-block Chevy hooked to an AMC steering box. I had to have the hoses made to get them to work together. I was told that a steering box from a certain model-year of Chevy Caprice Classic would bolt up. Is this true? And if so, what year model(s) will work?
Answer: After some 30 years of use, those power steering boxes take a lot of abuse and do wear out. In our January 2008 issue, we had an extensive article on how to rebuild the steering box, so you might want to see if you can find a copy. It does take a bit of skill and some special tools make it a lot easier.
The steering box in your Jeep was built by Saginaw, and they provided a lot of steering systems for other manufacturers that somewhat look alike. Even the ones that appear to be identical can have different ratios, different feel, and can even turn in the opposite direction. The great news is that Jeep used basically the same steering box for a lot of years, with different ratios to match the vehicle's wheelbase. This is the 800-series, and the better of the bunch have the number "76" cast into the side. These used a four-bolt mounting system versus only three, had larger bearings and some extra strengthening ribs, plus a few other things to actually make them better. It is definitely worth the time to locate a "76"-marked box. I believe that early Jeep Wagoneers used this box, too. Ratios can vary from 20:1 to 13:1. (The higher the ratio, the slower the steering.) There are even some boxes with variable ratios.
You can check out the ratio by turning the box manually from lock to lock. The fast ratio will take about 3 1/3 turns, and a slow ratio about 4 1/4 turns. There are internal stops in the boxes that limit just how far the box can be turned, and these can vary between applications, so you want to make sure the box has enough turning ability to match your steering system. Generally speaking, in a Jeep you need a minimum of 3 3/4 turns from lock to lock.
Fullsize rear-wheel-drive GM cars used the 800-series steering boxes, too, but not all of them are the "76 boxes" and they interchange directly with the Jeep steering boxes. Do watch out for the smaller 605-series steering boxes that were used in some of the intermediate-size cars.
All the steering boxes built after 1980 used metric O-ring fittings instead of the flared nut fitting. There are conversion pieces available. I believe that Speedway Motors (www.speedwaymotors.com) as well as steering box rebuilders such as PSC (www.pscmotorsports.com) can supply them to you.
Keep in mind that steering boxes take a lot of abuse over the years so when looking for a replacement make sure that it is not leaking fluid out of the selector shaft or the end cover. In fact in reality you would be better off buying a rebuilt unit from some one like PSC. Might even want to Google something like "rebuilt steering box" or "performance steering boxes" and you will find lots of companies to consider.
Oh, and make sure the box steering shaft is centered when you install it by counting the number of turns it takes from full lock to full lock and then making sure it's set at half that number from full lock on one side. The "flat" on the steering box input stub shaft should be facing up.
Dept. Of Corrections: High-Boy Tranny Tips
In our September '09 "Techline," I answered a question titled "Wants Stick Back in His High-Boy." Apparently, I really didn't go into enough detail and fully answer the question correctly. Hey, sometimes I just don't have all the answers. But faithful readers sometimes do.
Mike Strauss of Junction City, Kansas, had this to say: "A couple words of caution to the guy wanting to put a four-speed behind his 460. Be sure to check if the engine is internally or externally balanced. It is much easier to put the four-speed behind an internally balanced engine in this year of truck. The flywheel required for the externally balanced engine is much thicker than the internally balanced version. Keep in mind that there were no Ford trucks made in the '70s that were mated to a manual transmission. A flywheel from an FE 360 or 390 has a neutral balance and will bolt up to the internally balanced 460. Use one with the larger clutch if possible. Also be careful not to force the input shaft into the rear of the crank. A 460 crank sticks out further. You will probably need to space the tranny back about 1/4 inch. The 351M bellhousing works with this combination with the spacer. My setup with a Kevlar clutch disk has been trouble-free for years under some severe abuse. Good luck."
Then, from Mark Rayer came this bit of wisdom: "Personally, as a '73-79 F-Series guy, I would rather have a C6 behind a 460 than an NP 435. But if Mike really wants a manual tranny, that's his deal. First off, the title of the Q&A implies that his truck has a divorce-mounted transfer case since he calls it a High Boy. That doesn't always mean people know what they are talking about by calling their truck a High Boy, but let's assume his truck was made before April '77. Very few F-250 4x4s in 1977 came with both a 351M/400 and NP 435 combination, but that would be the tranny and bellhousing he would want. That is, assuming he wants to stay with the original-style divorced transfer case. The 460 didn't come with a manual tranny till the mid-'80s, so getting the right parts to match up is a lot harder than a simple removal/replacement swap, and that is why the 460 swap to the older 4x4 is more likely to run a C6 tranny. His best bet is to get a 460 swap kit from Bronco Graveyard to fit a manual tranny. He also needs to figure out if his 460 is internally or externally balanced. In reality, if he really wants to go through all the work of swapping in a manual tranny, he might as well do a NV 4500 swap and have overdrive."
Thanks much for the additional help, guys.