CILO

Hi all,

for the past month or so I've been trying to locate the source of vibration coming from the drivetrain. yesterday while checking my ujoints i noticed that there is some play at the rear companion flange. The front flange is stiff which leads me to guess that this is what's causing the vibration. Has anyone ever run into this problem? After looking at the FSM, I see that there's a lock nut keeping the flange in place. is it possible the nut may have come loose?

any help in this is appreciated

thanks

GSGALLANT

Usually the nut comes loose. In extreme cases, your bearing(s) could be bad. The nut is staked to keep it from turning. Unstake it, torque it to spec, then restake it. There is a spec for bearing preload that you can check to ensure that the nut is tightened correctly... it is a little tricky to check with the transfer case (I assume you mean the end at the transfer case) or the differential completely assembled, because you must check it within the backlash of the gears.

CILO

Thanks for the response!

One question though. You make it sound as if its common for this to happen. Is that the case? cause now you've got me thinkin. I recall seeing several posts mentioning a vibration at about 50mph. Could that lock nut you're referring to be the culprit?

1985 4Runner

The companion flange is not needed according to Jess at High Angle Driveline.

I just put a new shaft/yoke in & didn't re-install the companion flange. Pull it off & reinstall & see if that solves your vibration problem.


New (without flange)






Old (with flange)

Flash319

I just solved a vibration problem on my 89 Extracab. The rubber cross member mount had broke away from the cross member. Just one side of it. After putting in a new(spare) mount the vibration was gone. This is all after replacing a $250 hanger bearing. Something to check.

CILO

1985, (or should I say Spidey)

yours looks completely different from mine. Mine has 4 bolts sticking out of it and these bolts are what hold the drive shaft. I'm not sure what part you're referring to. What's the name of that new part shown in your first picture?

GSGALLANT

In the rear differential, there is a spacer behind the bearing that gets deformed when you torque the flange to spec, and you check the bearing preload to ensure that it is correct. If you have any sort of vibration in your driveshaft, over time I would think that would tend to further crush (slightly) the spacer to the point that the output shaft would be a bit loose (and the torque applied by the staked nut would be lowered) at a given nut position. Some people have corrected this by installing a solid spacer instead of a "crush" spacer.

I don't believe (but I could be wrong) that the same applies to the transfer case output shafts. somebody chime in if I'm wrong, but I think the FSM just calls for torquing the nut to spec, and not having to check the bearing preload?

CILO

FYI all,

I finally had some time last night to unbolt the drive shaft and inspect the lock bolt holding the companion flange. Turns out the bolt was loose after all. Unfortunately, I didnt have the right size socket to fit in that bolt and I couldnt pull out the dimple that locks the bolt in place. so i had to use an adj wrench to grab onto the outer lip of the bolt and try to force the bolt tighter. I was able to turn it a little less than a quarter doing it this way so I left it like that, reassembled, and took it out for a spin.

So now I'm on the highway approaching 50mph and expecting to hear the usual humm. However, the usual hum had become a fraction of what it use to be! ( at this point a light came from the sky and the angels from heaven sang in unison: HAAAA LE LUYA, HAAAA LE LUYA, HALELUYA HALELUYA, HALEEEEE LUYAAAAAA, LOL) I had found the source of my vibrations. Now I just gotta get a new bolt, the right socket, and lay this issue to rest....... And move onto the next, lol.............

CLIFF NOTES:
If your vehicle vibrates over 50, you feel the vibration in the shifter, and when driving over 50 you disengage the overdrive and the vibration stops momentarily, then you should inspect the companion flange lockbolt

Marc P

I had the same problem with the same solution. Mine was so loose it was leaking...

GSGALLANT

CILO,
Good to hear your problem is better! I recently tightened the rear output flange on my transfer case, when I pulled the driveshaft to replace a u-joint (which I still didn't finish). I got about an eighth of a turn on the nut in order to torque it to 87 ft-lbs. I still have to tighten the front one on the transfer case, but that will have to wait a bit until I finish the rear driveshaft work. Right now, I'm driving with front wheel drive only.

To stake/unstake the nut, use a punch and a hammer (be careful so you don't mangle the threads, then you can re-use the nut.)

The socket size you need is 30mm. Consider making a tool (piece of metal flat bar or angle iron with a couple of holes in it that you can bolt to the flange) to hold the flange while you tighten the nut. I just left the truck in park with the wheels on the ground and the emergency brake on, which was enough to hold the flange in place while I tightened it. I don't endorse this, although I can't see what damage it could cause when you're only torquing to 87 ft-lbs.

AuburnRunner

I need to bring this thread back to life...
I have vibration coming from the driveline... Checked underneath, and fluid is under the body at the companion flange... Removed the D-shaft, checked.. yup the nut was loose, tightened it up... Road test, and still vibration. Less but still there.
Question: Which bearings are further in from the seal that could be the problem? Are they accessible from under the truck or do I need to pull the Transfer for this one. Thanks for the help.

toyota_mdt_tech

All the time. Remove the prop shaft and rattle the flange nut down, stake it and secure the prop shaft back in.

MudHippy

Transfer case rear output shaft bearing, yes t-case requires opened (off truck prefferably) to replace. If you can't feel any significant play when you grab the shaft/flange, the bearing is fine.

As toyota mdt tech stated, the proper tightening procedure requires no specific torque, just tighten the nut (TIGHT) and stake. There's no bearing pre-load involved with that flange.

buckz6319

Hi guy's I would like to chime in...I had a bad vibration in my 95 4runner v6 4x4 and after replacing lots of rolling parts and reading lots of posts I have found the nut on my output shaft was loose to.I also retorqued(90 foot pounds) and restaked the best I could back to specs and hooked the drive shaft back to the companion flange.I went for a test drive and the vibration was gone I was so happy However to day I drove to work about 24 miles and during the drive I felt the vibs coming back again...now with this being said I think the old nut may have backed back off? or the bearing is bad? I really dont know how long the previous owner drove this 4runner with the vibs but I purchased it this way....so if I have to replace the output shaft bearing would it be the one just behind the nut or the others in side the t-case?..I have an automatic and I think it's a A340H...does any know what I should do next or have a link to a web site that will show me the steps to this progect I may have to do..........thanks for any help
Dwayne

chairwitharmrests

im not sure if the vibrations that you guys are experienceing are the same that I am, but when I hit bumps I could feel the shifter moveing, but I wouldnt consider it a vibration and it only does it over bumps at any speed. What could this be?

buckz6319

you may have a bad t-case mount,

AaronT

This is a very old but helpful thread I would like to dig a little more into.

I also had the major vibration after buying a 92 4runner with the A340H/VF1A I thought it was my tires for the longest time until the tires were almost bald and the vibration was still there. Took the truck in and they found that the 30mm bolt holding the driveline on was loose so they tightened it. Vibration decreased by half. The flange coming out of the transfer case for the rear of the vehicle has a lot of play in it still. My speedometer has since went out as well. I am going to remove the companion flange so I can get to the speedometer drive gear and replace it and also want to replace whatever bearing it would be that is causing the vibration. Could it be as simple as just the output bearing or would it be a lot of bearings in this situation. I do not wanna take it to the dealer I cannot afford it.

Also the tranny shifts fine but gets very hot on driving long distances. Is the torque convertor locking up because the speedsensor isnt functioning? I know there are 2 speed sensors and one is working to allow it to shift right now but the speedometer one is not.

Thingking of getting a better tranny cooler as well but do not want to overcool. any suggestions to a good model?

Thanks!
Aaron

buckz6319

I too had a loose rear companion flange nut and it being loose may have done more damage than I though ....I think this may interest you.I have started a thread on the tear down of a used donor A340H with chain drive t-case because I think .....I have the same problem as you and a lot of other folks with this tranny.I purchased this used unit to remove parts from that I thought were bad in my tranny .I took the parts from the rear output shaft companion flange up to the clutch basket and put them on my existing tranny that is still in my 95 4runner.

I did all this work only to discover that it didn't solve my issue and the parts I took of my existing A340H look as good as the donor parts(174,000 on my existing tranny parts)...and (101,000 miles on the donor tranny and the only problem with the donor tranny was slipping so I thought the t-case parts would be reusable so I removed the ones I thought I needed)...I know now after tearing down the donor tranny what's inside the hydraulic portion of this t-case and there are a lot of snap rings and c-clips and scarry stuff in there so have the whole tranny in pieces in 2 boxes at my home sooooooo if any one needs any parts please P.M. me any suggestions will be appreciated..by the way my rear output shaft has a lot of play also when going into gear and I can rotate it left/right with a lot of slack is this normal......are there a lot of these trannys with the same issue out there?

https://www.yotatech.com/forums/f116...t-case-156307/

saveapit

Man I wish this thread had a final solution. I too have the same issue: replaced u-joints, replaced rear dif, found the t-case companion nut loose, tightened, lesser noise but still there, came back after a few miles. Is the bearing shot from the loose nut? Can you just remove the case cover and replace? Are there more bearings you should do while you have it out? Where can you buy these bearings? My google searches pull up seals but no bearings? I've owned this 86' 22re/A340H for months now and I haven't even drove it except for test drives! Damn noise every time! I hope someone can post a valid reply on these bearings.

rhill

Bringing this back to life. I was having the same vibration issues. Tires/balance/alignment are all good so I thought it might be the drive shaft. Removed it and drove around in 4hi for a while and vibration was 100% gone. Whoopee! Took the shaft to a shop to get it serviced, put it back on, vibration still there!!! I just found this thread so I haven't checked that bolt yet. If I remove the drive shaft from the transfer case will I be able to see the bolt in question? I'm not quite sure on all the terms being thrown around and I'm getting confused. Any other ideas on what my issue could be after doing the FWD test?