'94 4Runner ADD/Hub Question - ADD
11-14-2013, 09:40 AM
#1
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
'94 4Runner ADD/Hub Question - ADD
I just got this 1994 3.0 sr5/v6 4x4
My question is this:
When engaged in 4x4, i 'feel' the t-case engage, the driveshaft locks in, the light comes on, the vacuum is proper at the front axle (goes from driver side suction to passgr side suction on the diaphragm at the axle), but the front tires don't lock in.
Am I having a hub issue?
Can I just convert from the auto hubs to manual, and be fine?
If so, OK to pick up the manual hubs (Aisin) at the boneyard, or go with warn or other...
Not trying to sink a ton of money, just need the dang 4x4 to work!
Thanks for any help!
My question is this:
When engaged in 4x4, i 'feel' the t-case engage, the driveshaft locks in, the light comes on, the vacuum is proper at the front axle (goes from driver side suction to passgr side suction on the diaphragm at the axle), but the front tires don't lock in.
Am I having a hub issue?
Can I just convert from the auto hubs to manual, and be fine?
If so, OK to pick up the manual hubs (Aisin) at the boneyard, or go with warn or other...
Not trying to sink a ton of money, just need the dang 4x4 to work!
Thanks for any help!
11-14-2013, 10:26 AM
#2
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
http://www.off-road.com/trucks-4x4/t...tem-19259.html
After reading this, it seems I either have a hub problem on both sides, or an actuator problem or a sleeve problem? There is vacuum on the driver side of the acutator on the diff in 2wd and passge side in 4wd, but I do not know if its 15 lbs...
After reading this, it seems I either have a hub problem on both sides, or an actuator problem or a sleeve problem? There is vacuum on the driver side of the acutator on the diff in 2wd and passge side in 4wd, but I do not know if its 15 lbs...
11-14-2013, 10:37 AM
#3
Registered User
Join Date: Sep 2007
Location: San Francisco East Bay
Posts: 8,254
Likes: 0
Received 822 Likes
on
649 Posts
You need to find out if the problem in the hub (unlikely, but someone could have messed with it) or in the ADD. Since the light comes on, it sounds like the ADD is engaging. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
So I would start by putting the front on jack stands. When you turn the wheel, the half-shaft SHOULD turn (the wheel is permanently connected to the half-shaft through the flange), but the opposite side wheel should not (the ADD disconnected). If the half-shaft doesn't turn, you need to disassemble the hub to see why. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
If the the wheels are connected to the half-shaft, use a vacuum pump to shift the ADD back and forth to see if that engages. (You could start the truck and use engine vacuum, but be REALLY careful since it's on jack stands.)
So I would start by putting the front on jack stands. When you turn the wheel, the half-shaft SHOULD turn (the wheel is permanently connected to the half-shaft through the flange), but the opposite side wheel should not (the ADD disconnected). If the half-shaft doesn't turn, you need to disassemble the hub to see why. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
If the the wheels are connected to the half-shaft, use a vacuum pump to shift the ADD back and forth to see if that engages. (You could start the truck and use engine vacuum, but be REALLY careful since it's on jack stands.)
11-14-2013, 10:43 AM
#4
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
You need to find out if the problem in the hub (unlikely, but someone could have messed with it) or in the ADD. Since the light comes on, it sounds like the ADD is engaging. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
So I would start by putting the front on jack stands. When you turn the wheel, the half-shaft SHOULD turn (the wheel is permanently connected to the half-shaft through the flange), but the opposite side wheel should not (the ADD disconnected). If the half-shaft doesn't turn, you need to disassemble the hub to see why. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
If the the wheels are connected to the half-shaft, use a vacuum pump to shift the ADD back and forth to see if that engages. (You could start the truck and use engine vacuum, but be REALLY careful since it's on jack stands.)
So I would start by putting the front on jack stands. When you turn the wheel, the half-shaft SHOULD turn (the wheel is permanently connected to the half-shaft through the flange), but the opposite side wheel should not (the ADD disconnected). If the half-shaft doesn't turn, you need to disassemble the hub to see why. http://personal.utulsa.edu/~nathan-b...26addcontr.pdf
If the the wheels are connected to the half-shaft, use a vacuum pump to shift the ADD back and forth to see if that engages. (You could start the truck and use engine vacuum, but be REALLY careful since it's on jack stands.)
Possibly something inside the front diff?
And, Thanks for the reply!
11-14-2013, 10:54 AM
#5
Registered User
Join Date: Sep 2007
Location: San Francisco East Bay
Posts: 8,254
Likes: 0
Received 822 Likes
on
649 Posts
Hmm. Do the wheels turn in opposite directions? (that's the correct action of a differential)
This suggests that the ADD IS engaged. I suppose you could block one wheel (anything to keep it from turning), and try to turn the the other wheel. In 4wd you shouldn't be able to. But if you can, does the front drive shaft turn? That suggests the ADD is working but your transfer case is not.
This suggests that the ADD IS engaged. I suppose you could block one wheel (anything to keep it from turning), and try to turn the the other wheel. In 4wd you shouldn't be able to. But if you can, does the front drive shaft turn? That suggests the ADD is working but your transfer case is not.
11-14-2013, 11:44 AM
#6
Registered User
Join Date: Jul 2012
Location: Northern Colorado
Posts: 1,776
Likes: 0
Received 109 Likes
on
81 Posts
I'll echo what scope said - make sure both wheels are turning in the opposite direction. If the half-shafts turn but one wheel doesn't, that's a hub problem on the non-turning wheel. (or possibly a broken CV shaft inside the hub.) With an open diff, if even just one wheel is free-wheeling, it's like not having any 4WD at all.
If the light comes on, it's highly likely the ADD is locking, because the switch for the light is activated by the movement of the ADD into lock.
If the light comes on, it's highly likely the ADD is locking, because the switch for the light is activated by the movement of the ADD into lock.
11-14-2013, 12:14 PM
#7
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
I'll echo what scope said - make sure both wheels are turning in the opposite direction. If the half-shafts turn but one wheel doesn't, that's a hub problem on the non-turning wheel. (or possibly a broken CV shaft inside the hub.) With an open diff, if even just one wheel is free-wheeling, it's like not having any 4WD at all.
If the light comes on, it's highly likely the ADD is locking, because the switch for the light is activated by the movement of the ADD into lock.
If the light comes on, it's highly likely the ADD is locking, because the switch for the light is activated by the movement of the ADD into lock.
2wd. engine off.
pass wheel turns freely, cv shaft turns, drive shaft not turn, driver wheel not turn.
driver wheel turn wheel, cv shaft turns, drive shaft not turn, pass wheel not turn.
exact same in 2wd, engine on.
engine on, 4wd (light on)
turn pass wheel, cv shaft turns, driver wheel turn opposite dir, driveshaft turns but not an exact ratio (meaniing wheel turns 1 revolution, driveshaft only 1/4 or so)
same thing opposite side.
engine on, 4wd (light on)
turn driveshaft, both wheels spin fwd or rev
engine on, 2wd
turn driveshaft, nothing turns either wheel or cv (supposed to happen)
jack all 4 up, 4wd (h or L), back wheels turn no prob, front wheels only barely trun and not same speed as back..
so differential or transfer case problem, being that my add is engaged as according to front end being locked in in 4wd?
Last edited by DocShock; 11-14-2013 at 12:23 PM.
Trending Topics
11-14-2013, 12:25 PM
#8
Registered User
Starting to sound like a transfer case problem. Your description of the 4wd tests sound normal. With the 4runner not jacked up, in 2wd and you should be able to spin the front drive shaft by hand. When in 4wd (still on the ground, vacuum pump or engine on, and in neutral) you shouldn't be able to turn the front drive shaft by hand (diff functioning normally).
11-14-2013, 12:29 PM
#9
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Starting to sound like a transfer case problem. Your description of the 4wd tests sound normal. With the 4runner not jacked up, in 2wd and you should be able to spin the front drive shaft by hand. When in 4wd (still on the ground, vacuum pump or engine on, and in neutral) you shouldn't be able to turn the front drive shaft by hand (diff functioning normally).
DAMN! started out thinking a simple vacuum problem, easy fix.
I guess that's why the guy didn't 'bargain' when i low balled him.. oh well, i got the a/c fixed pretty easily.
So what are common issues with the t-case in these bad boys? Ive never pulled one, and don't want to sink a ton of $ into this thing, if I don't have to!
11-14-2013, 12:46 PM
#10
Registered User
Ours are chain driven t-cases, so might be as simple as a broken chain. Next question would be why did the chain break? Won't know whats up until its out and you open it up, or take it to a shop to have them do the work. T-cases aren't too complicated inside. That being said, I've never had mine off. I'm sure those with more experience here will start chiming in. I'm sure there are threads aplenty with transfer case tear downs and troubleshooting though
11-14-2013, 12:54 PM
#11
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Ours are chain driven t-cases, so might be as simple as a broken chain. Next question would be why did the chain break? Won't know whats up until its out and you open it up, or take it to a shop to have them do the work. T-cases aren't too complicated inside. That being said, I've never had mine off. I'm sure those with more experience here will start chiming in. I'm sure there are threads aplenty with transfer case tear downs and troubleshooting though
I appreciate the reply!
I'll start searching for t-case swaps, etc.
If I can find one cheap and a good article to pull it, maybe eventually I will get to tearing this one apart!
If not, I'll be 2wd for awhile, LOL
11-14-2013, 12:59 PM
#12
Registered User
At least it sounds like you figured it out before you needed the 4wd to get outta somewhere. Nothing like taking a 4wd where you shouldn't only to find out its only a 2wd!
11-14-2013, 01:02 PM
#13
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Dangit.
11-14-2013, 01:28 PM
#14
Registered User
Join Date: Jul 2012
Location: Northern Colorado
Posts: 1,776
Likes: 0
Received 109 Likes
on
81 Posts
Before you buy a new (used) transfer case and go to the work of putting it in, go inside the cabin and pull the top off the t-case shifter mechanism and make sure the linkages and shift rails are all working properly. It could be that one of the shift rails is out of place and not being moved by the lever. The right shift rail is the one that shifts it from 2WD to 4WD. Forward is 4WD, and back is 2WD (just the opposite of the markings on the knob.)
Since your 4WD light is working properly, I'm not hopeful that this is the problem, but it's a fairly quick inspection and could save you some work.
BTW, we should ask. Is this an auto or a manual transmission? The automatic uses a special transfer case, I believe, that is somewhat integrated with the transmission and has more involved shifting logic.
Since your 4WD light is working properly, I'm not hopeful that this is the problem, but it's a fairly quick inspection and could save you some work.
BTW, we should ask. Is this an auto or a manual transmission? The automatic uses a special transfer case, I believe, that is somewhat integrated with the transmission and has more involved shifting logic.
Last edited by RJR; 11-14-2013 at 01:31 PM.
11-14-2013, 01:33 PM
#15
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Before you buy a new (used) transfer case and go to the work of putting it in, go inside the cabin and pull the top off the t-case shifter mechanism and make sure the linkages and shift rails are all working properly. It could be that one of the shift rails is out of place and not being moved by the lever. The right shift rail is the one that shifts it from 2WD to 4WD. Forward is 4WD, and back is 2WD (just the opposite of the markings on the knob.)
Since your 4WD light is working properly, I'm not hopeful that this is the problem, but it's a fairly quick inspection and could save you some work.
BTW, we should ask. Is this an auto or a manual transmission? The automatic uses a special transfer case, I believe, that is somewhat integrated with the transmission and has more involved shifting logic.
Since your 4WD light is working properly, I'm not hopeful that this is the problem, but it's a fairly quick inspection and could save you some work.
BTW, we should ask. Is this an auto or a manual transmission? The automatic uses a special transfer case, I believe, that is somewhat integrated with the transmission and has more involved shifting logic.
I did recently take the top of the t case shfter mech off to inspect everything. I thought I got it all back lined up properly, but will re-take it apart and test it ( i have to replace that stupid little light bulb anyways)
Thanks, will repost what happens!
11-14-2013, 01:50 PM
#16
Registered User
Join Date: Jul 2012
Location: Northern Colorado
Posts: 1,776
Likes: 0
Received 109 Likes
on
81 Posts
Here's a link to "how it works" for your transfer case. Might give you some insights as to what to look for.
http://www.autoshop101.com/forms/AT09.pdf
http://www.autoshop101.com/forms/AT09.pdf
11-14-2013, 01:51 PM
#17
Registered User
Join Date: Sep 2007
Location: San Francisco East Bay
Posts: 8,254
Likes: 0
Received 822 Likes
on
649 Posts
You probably have the A340H transmission (I'm not certain who gets which). The transfer case is "part of" the rest of the transmission (in that they both use ATF and have a fluid connection; it's all filled through the one filler tube). So you're not likely to find a transfer case by itself.
My first guess (and the first item on the diagnostic checklist) is the transfer shift linkage. http://personal.utulsa.edu/~nathan-b...32prelimin.pdf I've never taken one apart, but I wouldn't be surprised if you are moving the transfer position switch correctly (which triggers the VSVs to engage the ADD) but not moving the lever on the transfer case that engages the C4 clutch. (The A340H transfer case changes speeds H/L electronically to prevent you from shifting at a too-high speed, but the H2-H4 engagement is directly driven by the shift lever)
My first guess (and the first item on the diagnostic checklist) is the transfer shift linkage. http://personal.utulsa.edu/~nathan-b...32prelimin.pdf I've never taken one apart, but I wouldn't be surprised if you are moving the transfer position switch correctly (which triggers the VSVs to engage the ADD) but not moving the lever on the transfer case that engages the C4 clutch. (The A340H transfer case changes speeds H/L electronically to prevent you from shifting at a too-high speed, but the H2-H4 engagement is directly driven by the shift lever)
11-18-2013, 09:51 AM
#18
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
transfer case question, automatic v6
Havent gotten a chance to pull the pan on the tcase yet. Does anyone know if you can see the chain from there?
I checked the linkage, and all seems to be functioning properly there. I have no problem shifting, and the linkage connected to the 'switch' on the driverside of the tcase goes through the positions well.
3 questions:
Anyone know if there is any electronic part on the tcase that could of failed (ie, that switch on the driver sided that the linkage connects to)
Can you access and/or see the chain or any other issues by pulling the pan on the bottom of the tcase?
I can tell someone has been in there before, as there is gasket goop down there.
btw, it goes in to 4L (which in my case is 2L, since the tcase is not engaging)..not sure if this is a transmission function or not?
Thanks
I checked the linkage, and all seems to be functioning properly there. I have no problem shifting, and the linkage connected to the 'switch' on the driverside of the tcase goes through the positions well.
3 questions:
Anyone know if there is any electronic part on the tcase that could of failed (ie, that switch on the driver sided that the linkage connects to)
Can you access and/or see the chain or any other issues by pulling the pan on the bottom of the tcase?
I can tell someone has been in there before, as there is gasket goop down there.
btw, it goes in to 4L (which in my case is 2L, since the tcase is not engaging)..not sure if this is a transmission function or not?
Thanks
11-18-2013, 09:54 AM
#19
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
You probably have the A340H transmission (I'm not certain who gets which). The transfer case is "part of" the rest of the transmission (in that they both use ATF and have a fluid connection; it's all filled through the one filler tube). So you're not likely to find a transfer case by itself.
My first guess (and the first item on the diagnostic checklist) is the transfer shift linkage. http://personal.utulsa.edu/~nathan-b...32prelimin.pdf I've never taken one apart, but I wouldn't be surprised if you are moving the transfer position switch correctly (which triggers the VSVs to engage the ADD) but not moving the lever on the transfer case that engages the C4 clutch. (The A340H transfer case changes speeds H/L electronically to prevent you from shifting at a too-high speed, but the H2-H4 engagement is directly driven by the shift lever)
My first guess (and the first item on the diagnostic checklist) is the transfer shift linkage. http://personal.utulsa.edu/~nathan-b...32prelimin.pdf I've never taken one apart, but I wouldn't be surprised if you are moving the transfer position switch correctly (which triggers the VSVs to engage the ADD) but not moving the lever on the transfer case that engages the C4 clutch. (The A340H transfer case changes speeds H/L electronically to prevent you from shifting at a too-high speed, but the H2-H4 engagement is directly driven by the shift lever)
11-18-2013, 10:03 AM
#20
Registered User
Thread Starter
Join Date: Nov 2013
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Here's a link to "how it works" for your transfer case. Might give you some insights as to what to look for.
http://www.autoshop101.com/forms/AT09.pdf
http://www.autoshop101.com/forms/AT09.pdf
lol
So, seems scope and rjr are correct! seems the c4 clutch may be the culprit, possibly?
Inevitably, it looks like dropping the tcase is a must, ehh?
