Straight Axle Swap with a Chevy Dana 44 Axle
(Last update: 12/14/04 )
ALSO: Check out the pictures from Ed's 91 4Runner D44 swap
This swap was similar to Jason Wilson's
swap (AKA "Eight") who helped me out a LOT with the whole project.
Some differences between our swaps:
Comparisons to some other swaps:
and turned knuckles
Driver's side closeup
12 degrees of rotation
I picked up a '72-ish Chevy 1/2-ton (6-lug) 67.5" wide wms-wms (wms = wheel mounting surface) Dana 44 axle for $150 complete w/ disk brakes, locking hubs, aftermarket steering stabilizer, ~22" stainless steel brake lines, u-bolts and plates, steering arm, tie rod, lug nuts, flat-top knuckles on both sides, and CV style drive shaft. It had 3.07 gears so I needed a new 3.92-up carrier to install 5.38 gears. I also found out later that it has the older small-diameter axle shafts and u-joints, so those were changed out. The older style axle also used a different type of seal against the spindle than the newer ones, so the spindles were changed out as well.
Update: I've run the axle now with anywhere from 2-8 degrees of caster. I've found that I like how it drives best with closer to 2 degrees. With less caster, the steering is easier and more responsive, and there is less bumpsteer felt in the steering wheel. I also think that too much caster helped contribute to the "death wobble" that I had when I first did the axle swap.
Update: I changed out the double spindle nut w/ lock washer
setup for these cool Ford single locking nuts: Quick Dana 44 Spindle Nut
Update: On Ed's 91 4Runner D44 swap, instead of using a big, thick shim, I welded some flat bar to the front of the perch, and then ground the flat bar and perch down to the desired angle. This is time-consuming, but works well. It keeps from adding unnecessary lift, and leaves more clearance between the drag link and the springs (and tie rod if you run high-steer). That way you don't have to run extra tall steering arms or spacers. To take out a little lift when I went to 37's, I went back on my axle and ground the perch and shim down to normal height, and removed the spacer on the driver's side perch.
I first used stock '84-88 Toyota rear main and second leaves (moves axle forward 2" from
stock), plus 4 leaves from a Mazda 2wd pack. I was able to arrange the
Mazda leaves under the Toyota leaves so that the rear of the leaves step down
fairly evenly in length and I only have to cut the fronts. The fronts were
cut for about 1.5" steps.
Main- .280"; 2nd- .240"; 3rd- .280"; 4th- .240"; 5th- .240"; 6th- .200"
These turned out to be WAY too soft and too tall so I built another pack using Rancho top leaves from a 3" lift pack, and the lower 3 leaves from a stock Toy front pack. They are pretty stiff, but they still flex decent with the wider axle (more leverage). I plan on changing the springs again soon, possibly using Wagoneer springs.
4/02- I'm now running a set of used 4" lift Allpro
springs up front with the shackle hanger moved from under
the frame to through it. These springs are working great for me.
Spring Hanger/Front Crossmember-
The dropped front spring hanger crossmember is made of 2 x 2 x .25" square tubing (probably overkill, but it was free). The hangers themselves were cut from 3.5 x 3.5 x .25" square tubing. I also built a receiver hitch into the center since my tow hook was removed to mount the crossmember..
The hangers are 27.5" on center to match the perches on the narrowed axle. Stock straight axle Toyota hangers and perches are 29" on center.
The hangers have a 2" drop built into them (4" from the bottom of the frame) compared to a stock straight axle Toyota, but the distance from the front of the frame is the same, about 2". I also drilled a second set of holes 1" forward of those for more mount options.
TIP: To keep the sides of the hanger from getting bent sideways when hit, run a steel spring bushing sleeve. This allows you to tighten the bolt down on the sleeve, and ties both sides of the hanger together, which makes it MUCH harder to bend. Mine have held up great this way.
Update- Ever since the swap was completed, I've run the spring in the 1" forward hole. I also went back and trimmed the excess hanger material under the hole to keep it from hitting rocks and getting the very bottom edge bent in. Now the spring and the bolt are about the only thing that can get hit.
Stock rear shackle hangers were mounted to the bottom of the frame. The hangers I used are the second set of shackle hangers I had installed with my Chevy rear spring swap. I removed them and installed a double shackle in the rear instead. It was easier for me to do that than search for another set of shackle hangers.
At first, I planned to use my old stock rear shackles, but I ended up making my own longer ones out of 3/8" x 2" flat bar.
I don't really like how the hangers on the bottom of the frame make the shackles and rear of the springs hang down so low, so I'm thinking of mounting some new hangers through the frame similar to the stock mounting method.
UPDATE 4/02- I've moved the shackle hangers to through-the-frame
(duplicated the stock shackle hangers) and changed to some Allpro
4" springs. I'm much happier with this setup and I'd recommend always
mounting the shackles this way.
Pitman arm- Stock IFS pitman arm, end removed and a Chevy- tapered insert from FRORFab ($20) was pressed in. Although I've yet to have any problems, the pitman arm is probably the weak link in my steering setup, so I carry a spare on the trail.
Flat-top Knuckle- I exchanged my passenger's side flat-top knuckle at Roggy Enterprises for one that was machined, drilled, and tapped to accept a steering arm ($50 exchange), basically a mirror image of how the driver's side came from the factory. I had to replace the ball joints in that knuckle as well since they were removed for machining.
Steering arm- I used a Roggy Ent. passenger side steering arm ($85).
I re-used the original studs, cone washers, and nuts from the driver's side, on the pass. side steering arm to save money.
Drag Link- is a Rockstomper Rock Rod ($60) using '85 Blazer drag link ends. Autozone (McQuay-Norris) part numbers are ES2026R & ES2027L for the ends. Drag link overall length is about 40-1/2".
Tie Rod- A sleeved (3/8" wall) Rockstomper Rock Rod ($75) runs below the springs using an '85 Blazer end (ES2234R) and a '79 Dodge W200 truck (w/ 4500lb axle) end (ES2010L). Tie rod overall length is about 53-5/8".
Total cost for tie rod and drag link ends was just under $120 w/ tax and a "lifetime warranty"
Note: The Toyota pitman arm is very short compared to a domestic pitman arm or steering arm. This means it cant steer the D44 to its full range. To solve this problem, I had the steering arm on the axle re-drilled and tapered about 2" back from the original hole and moved the drag link back to that hole. This effectively shortens the steering arm and makes for a better match to the Toyota pitman. If you run high-steer, you can effectively do the same by running the drag link to the tie rod, which is already mounted in rearward holes. This is known as an Inverted "T" setup.
Also check out Billavista's Dana 44 steering research page for lots of other info & options.
I've also decided that I will probably not ever switch to high-steer (tie rod
above the springs). With the tie rod below the springs, I am free to move my
axle forward/backward as I wish and not ever have to worry about the tie rod and
drag link interfering and/or needing to move the steering box foward to prevent
it. As you can see, the tie rod is actually in front of the drag link as it
High-Steer vs. Low-Steer on a Dana Axle
High-steer puts all the steering loads on the bolt-on steering arms and puts extra loads on the upper ball joints. Low-steer spreads the loads between the top bolt-on steering arm and the strong cast arms. Since the cast arms are between the upper and lower steering joints, they distribute the load across both joints more evenly. Either setup will normally work just fine, however under high stress like when adding hydro-assist, the low-steer setup will have a strength advantage. High-steer is a little more likely to tear the arms off the knuckles and wear out the upper steering joints.
My point is, high-steer may be a bit over-rated. Don't shy away from "low-steer" simply because it is "low." That really isn't much of an issue, the axle itself is what limits ground clearance. Low-steer is actually a little stronger, cheaper, and in cases like mine it can be a lot easier to set up.
Bilstein 5100 series 14" travel shocks from Roggy Ent. ($120, part # F4-BE5-6250-HO). They measure 34.90" extended and 20.75" compressed which is longer than the popular Rancho RS9012's (but they have about the same travel), and were mounted accordingly. At rest there is about 5.75" of shock rod exposed.
I like a fairly firm shock and these shocks are fairly soft, so someday I'd like to upgrade to some Bilstein 7100's with custom valving.
Shock towers- '88 F250 shocks towers (part number E5TZ-18183A) purchased from Harold Ford in Sacramento ($10.85/ea).
I left part of the old IFS bracket on the frame rail where the shock tower is
now welded. This made for less junk to cut off, and kept me from having to
re-box in the motor mount support. And, since the IFS bracket is very strong and
spread over a large area of the frame, I didn't need to brace the tower to keep
it from tearing off the frame.
5-04- I swapped out the Bilsteins for Poly Performance BBCS shocks. These are firmer and I like them better. They are also longer, so I moved my lower shock mounts down a couple of inches.
The easiest way I've found to adapt the Chevy calipers to the Toyota brake lines is buy custom lines from Tony at Rock Equipment. Tell him you need some lines to go to the D44 under your Toy, he'll ask you how long you want them and whether your calipers have 3/8" or 7/16" banjo bolts. In a couple of days you'll have exactly what you need.
I also installed a 1" bore V6 brake master cylinder from a '92 pickup in order to be able to push enough fluid for the large Chevy calipers. This helped, but the pedal was still pretty soft and mushy.
UPDATE- I found a way to fix the mushy pedal and dramatically
improve the brakes over all.
I used receiver tubing to build a cheap, home-made, long-travel drive shaft.
I used the pinion end of my IFS drive shaft at the transfer case (transfer case flange was redrilled) welded to some 2x2x1/4" tubing. I chopped off the shaft leaving about 1" to slide into the square tubing. I had to grind small flat spots into the round tube until it could be pounded into the square tubing and then welded.
The Chevy pinion-end yoke was also chopped off with about an inch left and I tack welded sheet metal chunks in four places around the tube to help it fit snug and center itself. Then I filed those down until the yoke was a tight fit into the receiver tubing and welded it up.
Both yokes and tubes were pre-heated with a torch and then MIG welded.
The receiver tubing was $7.50/ft at S&K Steel and I used about 18" worth.
The price of the square driveshaft compared to a new long-travel one is
definitely worth it for a rockcrawler. It works great for rockcrawling, but not surprisingly,
vibrates at speeds over 25mph. Part of that is due to having a
lot of angle on the t-case u-joint, and no angle a the pinion joint.
A CV (double cardan) joint at the joint will help cure this part of the
UPDATE: I won a High-Angle
Driveline on the Marlin Crawler
To help reduce body roll on my daily-driven commuter/rockcrawler 4Runner, I installed a swaybar. I used a thicker one with shorter arms from a '90's V6 Toy truck, flipped over so that the bend went up and over the driveshaft instead of under it. The new swaybar frame mounts are several inches farther forward on the frame than the originals, so they were custom. I also made some disconnects using heim ends, similar to the Rockstomper disconnects.
The only real swaybar problem I have is that if I bottom out fairly hard, the driveshaft hits it. I think using one from a Tacoma will solve this problem since the bends are the same on both sides as well as sharper and deeper.
The disconnects also rattle on rough roads when installed, but that's not a big deal.
UPDATE: I've installed a Tacoma sway bar. The bar is stiffer than the old one and works very well. It has a deeper/wider bend that gives the driveshaft lots of clearance as I had hoped. However, the bend is deep enough that it also hits the transmission, so the bar had to be spaced down from the frame about 1-3/8". That worked fine until I moved my shackle hangers to through the frame which made it so the springs hit the sway bar mount brackets when the springs are compressed. Its not too bad though. They hit just after the bumpstops do, so I have to bottom fairly hard for them to hit. It hasn't been enough of a problem for me to bother fixing yet. If I plan on flying around at high speeds where I'll be bottoming out a lot, I just remove the whole sway bar.
Contact Info for Parts Sources:
City Differential, Rancho Cordova, CA, (916) 852-7109
Chevy Dana 44 width possibilities using stock length axle shafts:
(Axle widths are, WMS-WMS - wheel-mounting-surface to wheel-mounting-surface. Perch widths are center to center)
69" wide, 31.5" perches- stock Chevy 8-lug
65" wide, ~29" (Toy width) perches- long side cut down 2-3/8", use 70's
Ford long side axle shaft
Wagoneer axle dimensions-
Warn's axle shaft application page has some useful (but limited) axle shaft length info.
Stock Toyota front axle measurements for comparison:
Toyota Rear Axle Widths:
Cost Breakdown at time of swap-
Complete used axle- $150
Axle shim- $20
Short and long side axle shafts- ~$50
Pass. side knuckle machining- $50
Pass. side steering arm- $85
Drag link- $60
Tie rod- $75
Chevy shackles- $10
Mazda Springs- $35
Pass. side ball joints- $45
Tie rod and drag link ends- $120
Pitman arm insert- $20
Ford shock towers- $25
Brake master cylinder- $??
Brake line fittings- $10?
3.92-up carrier- $45?
Gear install kit- $100?
5.38 gears- $48
|Since my 4Runner is my daily driver, I got as much as
I could ready before the actual swap took place so that it could
be finished in one weekend. I didn't get as much done beforehand as
I had planned, so it was an extremely busy weekend. However, I had
lots of friends stop by to help get everything done.
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