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Discussion Starter · #1 ·
Greeting all - I've been away for quite a few months (my new employer does not allow internet access - I'm getting a lot of paper reading done at lunch but I'm way behind on my forums).

I just completed some work on the front drive axle and now the driveline binds when in 4WD (both hi & lo). 2WD works good. By binding - the effort to move (either forward or backward) increases w/ distance traveled. By the time I have covered about 10 ft I really have to slip the clutch and rev the engine and I am afraid to push it further and break something. This is my winter commuter car & 4WD is important to me.

I replaced the front differential, repacked & rebooted the CV joints (the old boots were 11 years old and beginning to look weathered - I converted a 2WD to 4WD 11 years ago - with out any driveline problems),did a big brake update and repacked hubs/wheel bearings and lubed the autolocking hub parts.

Both diffs are open. If I lift one side of the vehicle off of the ground and run the engine w/ 4WD engaged, all is well (I have done this on both sides). What this tells me is that the trans/transfercase, drive shafts & differentials are OK and that the problem has to be in either a front axle CV or a hub. Any suggestions on what to look for?
 

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Are all your tires the same size? What did you do to the front diff?
 

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Discussion Starter · #3 ·
Yes, 4 new tires - all the same size

For 11 years I had a ratio mismatch between front & back. 4.10 rear and 4.556 front (my fault - I asked the right question about rear axle ratio(s) on the wrong forum (a 4wd only forum) and got the wrong answer. After 9 blissfully ignorant years, the rear pinion failed (apparently the weakest link) and that is when I found out about my rear ratio. So I finally fixed the front and now it does not work. And yes I am **certain** about both the front and rear ratios in there now.
 

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Sure sounds like something is binding, different ratios F/R would be the first suspect since you were able to make it 10 feet or whatever, but you say you've got that straight. A problem before the diffs would be quicker to manifest due to more revolutions per foot. I can't see how the hubs would cause this, never really heard of a CV doing that but I can't rule it out either. It would be easy and worth checking to take the hub cap off and make sure the snap rings are properly installed in the ends of the CV shafts.
 

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aribert said:
Greeting all - I've been away for quite a few months (my new employer does not allow internet access - I'm getting a lot of paper reading done at lunch but I'm way behind on my forums).

I just completed some work on the front drive axle and now the driveline binds when in 4WD (both hi & lo). 2WD works good. By binding - the effort to move (either forward or backward) increases w/ distance traveled. By the time I have covered about 10 ft I really have to slip the clutch and rev the engine and I am afraid to push it further and break something. This is my winter commuter car & 4WD is important to me.

I replaced the front differential, repacked & rebooted the CV joints (the old boots were 11 years old and beginning to look weathered - I converted a 2WD to 4WD 11 years ago - with out any driveline problems),did a big brake update and repacked hubs/wheel bearings and lubed the autolocking hub parts.

Both diffs are open. If I lift one side of the vehicle off of the ground and run the engine w/ 4WD engaged, all is well (I have done this on both sides). What this tells me is that the trans/transfercase, drive shafts & differentials are OK and that the problem has to be in either a front axle CV or a hub. Any suggestions on what to look for?
The part I emboldened.....are you talking in a straight line, or when you try and turn, or both? If it does this in a straight line, you either have front and rear tires that are different sizes (or worn differently...that'll do it to) or different gear ratios. Don't put it in 4wd again and try to drive it, you'll only break something. Your transfer case should be allowing some slip between front and rear, unless it's strictly a "part time" unit, in which case you should never engage it on dry pavement or solid high-traction surfaces, it isn't built for it. Your front and rear tires don't travel the same distance to any given object, which is why any vehicle built for "full time" 4x4 operation will have a sort of limited slip built into the transfer case. There are alot of other guys on this form that can tell you more about this than I can, I'm surprised they aren't chiming in on this already.

To find out for sure exactly what's happening, you could put it on a couple of jackstands (same side), take it out of gear, put it in 4wd and rotate a rear wheel by hand a few revolutions and see whether the front and rear are turning the same number of times. Mark both tires that are in the air at the bottom of the sidewall with chalk, so you'll have a reference. If they're turning the same number of revolutions after about 20 or so times, then it's a tire size difference problem and easily solved with several hundred bucks. If not, then you still have a front/rear ratio mismatch problem and...it's easily solved with several hundred bucks ;)
 

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Binding in as little as 10 feet where it is so bad you are afraid to stall the engine is surely a gear miss match. Wear on a set of tires that are all the same size and brand will not cause binding that severe is such a short distance.

Did you count the teeth on the gears? If not then you wont know for sure. The stock diffs are not marked and neither are the gear sets. You have to count manually.
 

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betterthanyou said:
Binding in as little as 10 feet where it is so bad you are afraid to stall the engine is surely a gear miss match. Wear on a set of tires that are all the same size and brand will not cause binding that severe is such a short distance.

Did you count the teeth on the gears? If not then you wont know for sure. The stock diffs are not marked and neither are the gear sets. You have to count manually.
That's what i'm thinking as well. Despite your work, sounds like you still have a mismatch.
 

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Another way to tell is jack it up and set it on jack stands. Put it in 4low first gear and let it idle and watch the wheel speed from front to back. Same concept of the chalk but using the engine instead. What is your gear ratio now ??? Maybe what you have is 4:77's in the rear and 4:56's in the front. Close but more than enough to bind/lock it up. If you could find some loose gravel or dirt to drive briefly on you'll see if the rear is getting drug by the front or vise versa fronts getting pushed by the rear. That would sink the front suspension noticeably.... One other thing you could do is jack up the front, turn the wheel sharp one way, make sure the hubs are locked and spin the tire to feel the cv's for massive binding.
 

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Discussion Starter · #9 ·
All:

Thanks for the responses:
I have totally ruled out a gear mismatch. Yes I counted the teeth. I also blocked off the wheels on one side, marked the tires and let the clutch out and let the system run. I did this more than 5 times (lost count), letting it run from a few seconds up to a couple of minutes, 5+ times of random run time length, both in hi & low & in multiple gears. My tire marks stayed consistent. My rear axle is a corporate 10 bolt - per Jerry L it is not available in 4.556 or 4.77. I just spent $700 on 4 new tires, they have about 17 or 18 miles on them to date, they are all the same size.

This is a straight line issue.

One other point - after having the vehicle off the ground and running it, I tried to push it rearward w/ the hubs still locked, trans in neutral. I was not able to push it more than about 18 inches - it was binding too much for me to roll it. Normally I have no issue rolling the vehicle on level pavement.

On Monday night I took it out with a light snow cover on the roads (about 1/2 inch depth) that is where I got up to 10 ft in 4WD. I tried again on Wednesday on dry pavement and it was less distance.

I'll put it up on jack stands and turn the steering wheel to full lock and see if I can diagnose which side the issue is coming from - I hope this suggestion leads somewhere - I am so short on time this weekend, I really want to limit the dis-assembly to only there the problem is. I'll also check the snap rings on the ends of the axles.
 

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Since it has auto lock hubs you can rais the front off the ground, t case in 2wd spin the front drive line by hand to rotate everything. It will lock the hubs and you will quickly find an answer if it bindes up or not.
 

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Ok, so let's recap:

It's only when it's in 4 wheel drive that it binds, drives perfectly in 2 wheel drive, new tires, all same, guaranteed to have the right (identical) gears, front and rear having been verified both by counting teeth and by spinning tires to verify they turn at identical rate..

There's only one thing I can think of to check, and that's to pull the front driveline, put it into 4 wheel drive, and see what happens. If there's no problem moving, then the malfunction is in the front differential and not in the T-case. Not knowing much about that differential, I can't guess what could be causing it, but if it's binding only under pressure, maybe your gears aren't adjusted properly. I've never heard of a CV joint causing problems like you describe.
 

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Unlock the hubs, put tranny in neutral and spin the front driveshaft by hand...see what happens.
 

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aribert said:
All:

Thanks for the responses:
I have totally ruled out a gear mismatch. Yes I counted the teeth. I also blocked off the wheels on one side, marked the tires and let the clutch out and let the system run. I did this more than 5 times (lost count), letting it run from a few seconds up to a couple of minutes, 5+ times of random run time length, both in hi & low & in multiple gears. My tire marks stayed consistent. My rear axle is a corporate 10 bolt - per Jerry L it is not available in 4.556 or 4.77. I just spent $700 on 4 new tires, they have about 17 or 18 miles on them to date, they are all the same size.

This is a straight line issue.

One other point - after having the vehicle off the ground and running it, I tried to push it rearward w/ the hubs still locked, trans in neutral. I was not able to push it more than about 18 inches - it was binding too much for me to roll it. Normally I have no issue rolling the vehicle on level pavement.

On Monday night I took it out with a light snow cover on the roads (about 1/2 inch depth) that is where I got up to 10 ft in 4WD. I tried again on Wednesday on dry pavement and it was less distance.

I'll put it up on jack stands and turn the steering wheel to full lock and see if I can diagnose which side the issue is coming from - I hope this suggestion leads somewhere - I am so short on time this weekend, I really want to limit the dis-assembly to only there the problem is. I'll also check the snap rings on the ends of the axles.
OK ,YOU STILL HAVE THE ORIGINAL 2.3 AMIEGO REAR AXLE ,CORRECT, THEY ONLY CAME WITH 4.10 GEARS , WHAT IS THE FRT AXLE /DIIF IN YOUR TRUCK , ASSUMING IT IS ALL SO A 10 BOLT NOW WHAT DID IT COME FROM , THE FRT 10 BOLTS WERE AVAILABLE IN A LOT OF DIFF RATIOS, 4.10 4.30 4.55 4.77,

THE REAR 10 BOLT , UNLESS THE GEARS THEM SELVES WERE CHANGED , NEVER HAD ANYTHING BUT 4.10 , SINCE IT WAS THE MODIFIED 10 BOLT THAT CAME OUT IN 88 AND WAS USED ONLY IN THE PICKUP AND THE AMIEGO WITH THE 2.3 ENG. THE ONLY WAY IT COULD HAVE 4.55 ,SOME ONE WOULD HAVE HAD TO CHANGE THEM, THE GEARS ARE SWAP ABLE TO 4.55 , BUT THE EARLY TROOPERS ARE THE ONLY PLACE YOU WOULD FIND THEM , THE COMPLETE DIFF WILL NOT FIT THE LATE 10 BOLT HOUSING . JERRY
 

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Discussion Starter · #16 ·
With ears that are currently out-glowing Rudolph's nose, I am here to say: You were all correct in the gear ratio mismatch. Several of you mentioned manually engaging the front auto-lock hubs and checking the ratio. I did this on Saturday and this time the front and rear tire rotations were noticeably different. It took me quite a while to figure out why I kept getting the results that I wanted (same ratio front to back) - while checking for the ratio mismatch under engine power I was not using the brake (loading up the front auto-lock hubs) when shutting off the engine. Without a load the hubs would freewheel during shut down and when I got out of the vehicle they apparently stopped at the same rotation point - I am guessing rotor to pad friction.

So last night I crawled under the vehicle and turned each of the driveshafts and counted the wheel rotations. Front ratio is definitely a 4.1:1 (from an '01 Rodeo Sport). Back ratio was much more difficult to figure out anywhere from 4.3 to 4.6. While laying dumbfounded on my creeper I noticed that the rear diff did not have the two long bolts near the bottom like the 10 bolt axle has - when I replaced my damaged 10-bolt it appears that I bought a 12 bolt and never realized it.

This is my old axle asm - notice how the diff has two longer mtg bolts. http://i290.photobucket.com/albums/ll27 ... godiff.jpg
This is my axle today - all diff mounting bolts are same length http://i290.photobucket.com/albums/ll27 ... 260022.jpg I assume there is only the 10, 12 bolt corp axles and the Dana w/o removable diff - correct?

So now I need to pull the rear diff to confirm the ratio and then pull the front and replace to get a match. Most likely I had matching ratios the past two years while I was at times driving stupid to make sure I always kept the wheels in the snow and not in cleared ruts - why it did not bind up the first 9 years with the 4.556 front and 4.10 rear is a mystery to me. This is an expensive screw up on my part - I'll take the 23rd of Dec off w/o pay and try to button it back up on the 30th all other days are spoken for till after New Years.

So thank you all for your input - hopefully I'll have a useful 4wd in the beginning of the year.
 

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Well live and learn. The rear would be easier to pull apart maybe. I guess it depends on what ratio you want. We've all been there so don't feel to bad... I got a little confused between those two pics. The original rear axle was the small 10 bolt that matched the front in size and all correct ??? You scored the bigger axle for the rear and it's noticably bigger then the front now correct. I had the 12 bolt in my amigo with the 4:56's. I still have a rear amigo axle with 4:77's if it helps. Probly way to low but let me know.
 

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A 12-bolt is most likely 4.56...
 

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aribert said:
With ears that are currently out-glowing Rudolph's nose, I am here to say: You were all correct in the gear ratio mismatch. Several of you mentioned manually engaging the front auto-lock hubs and checking the ratio. I did this on Saturday and this time the front and rear tire rotations were noticeably different. It took me quite a while to figure out why I kept getting the results that I wanted (same ratio front to back) - while checking for the ratio mismatch under engine power I was not using the brake (loading up the front auto-lock hubs) when shutting off the engine. Without a load the hubs would freewheel during shut down and when I got out of the vehicle they apparently stopped at the same rotation point - I am guessing rotor to pad friction.

So last night I crawled under the vehicle and turned each of the driveshafts and counted the wheel rotations. Front ratio is definitely a 4.1:1 (from an '01 Rodeo Sport). Back ratio was much more difficult to figure out anywhere from 4.3 to 4.6. While laying dumbfounded on my creeper I noticed that the rear diff did not have the two long bolts near the bottom like the 10 bolt axle has - when I replaced my damaged 10-bolt it appears that I bought a 12 bolt and never realized it.

This is my old axle asm - notice how the diff has two longer mtg bolts. http://i290.photobucket.com/albums/ll27 ... godiff.jpg
This is my axle today - all diff mounting bolts are same length http://i290.photobucket.com/albums/ll27 ... 260022.jpg I assume there is only the 10, 12 bolt corp axles and the Dana w/o removable diff - correct?

So now I need to pull the rear diff to confirm the ratio and then pull the front and replace to get a match. Most likely I had matching ratios the past two years while I was at times driving stupid to make sure I always kept the wheels in the snow and not in cleared ruts - why it did not bind up the first 9 years with the 4.556 front and 4.10 rear is a mystery to me. This is an expensive screw up on my part - I'll take the 23rd of Dec off w/o pay and try to button it back up on the 30th all other days are spoken for till after New Years.

So thank you all for your input - hopefully I'll have a useful 4wd in the beginning of the year.
AH HAH, SO YOU HAVE A 12 BOLT REAR AXLE, FROM EITHER A LATE PICKUP OR A LATE AMEIGO 89-91 SINCE THEY ARE THE ONLY TWO THAT WOULD BOLT RIGHT UP, AND DEPENDING ON WHICH VEH IT CAME FROM YOU COULD HAVE THE 4.30 OR THE 4.56 AND IT LOCKING UP AS FAST AS IT DOES , MOST LIKELY IT HAS THE 4.56/4.55 THE PICKUP CAME WITH 4.10 4.30 AND 4.55 AXLES DEPENDING ON WHICH TRANS AND WHICH CHASSIS 2X4 OR 4X4 STARTING IN 88 A LOT OF THE 2WD PICKUPS AND IN 89 AMIEGOS CAME WITH 4.10 WITH DISC BRAKES, BUT ALL HAD DISCS IF 4WD AND THE GEARS DETERMINED THE TIRE SIZE
STANDARD TIRES 4.3 BIG TIRE PACKAGE 4.55
 

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Discussion Starter · #20 ·
bradzuzu:
For 9 years I had a 4.556 front diff and a 10 bolt (4.10) rear axle and I was oblivious to that fact (in 4wd there was no binding, there was a bit of transfercase hum over 40 mph and there was a 4 mpg drop in fuel economy) & I even occasionally drove it in 4wd on **dry** pavement. If the early morning traffic report said the roads were slick and icy or snow covered 10 or 15 miles to the west of home and the weather was headed east, I would drop into 4wd as I backed out of the driveway - easier than finding a spot to pull over to engage the autolock hubs in heavy commuter traffic.

I am hoping that with both front and rear ratios the same that the fuel economy drop will be a bit less.
 
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