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1st Gen 4Runner Vibration when letting off gas After OME 2.5" Lift
For those of you watching my build thread, you know that I just finished adding an OME 2.5" lift to my '87 Turbo. When I drove it to the paint and body place in fully stripped down condition, I noticed a loud vibration coming from the rear center when I let off the gas pedal at speed.
After a quick search, I realized this is very common after a 2.5" lift. From what I can tell, the steps are:
1) Reassemble the truck and see if the added weight in the rear causes enough sag to fix the problem
2) Get an alignment with the new tires (32x11.50 KO2s)
3) Check Rear Axle U-Joints
4) Check Front Axle U-Joints
5) Check Rear Pinion Nut
I'm hopeful #1-2 above will fix it. For those that have experienced this, are there any other ideas for when I get it back?
Also, when I had a similar issue on my '98 Tacoma, I simply dropped the Carrier Bearing using some washers and longer bolts. Is this not an option on our 1st gen 4runners?
The U-Joints look like a PITA to replace on these given how tight everything is! Note that I also removed the rear differential to apply new sealant it after a slight gear oil leak, but I don't think that fix caused any issues as it went really smooth.
Charles - well, you don't have a center dshaft bearing on your 4Runner, so there is nothing to "drop" there. When you say the U-Bolts look like a PITA, I think you mean u-joints? I'd suspect the u-joints, 30+ year old u-joints are begging to be changed anyway. The added weight of your topper may make the u-joints happier, but I'd probably still change them if it were me. When it's all back together if nothing else helps, they sell wedges I believe that sit under your leaf spring to angle the pinion up toward the tcase for a less severe dshaft angle.
Charles - well, you don't have a center dshaft bearing on your 4Runner, so there is nothing to "drop" there. When you say the U-Bolts look like a PITA, I think you mean u-joints? I'd suspect the u-joints, 30+ year old u-joints are begging to be changed anyway. The added weight of your topper may make the u-joints happier, but I'd probably still change them if it were me. When it's all back together if nothing else helps, they sell wedges I believe that sit under your leaf spring to angle the pinion up toward the tcase for a less severe dshaft angle.
Good to know there is no Cartier Bearing like a Tacoma - if I had the truck, I would have just looked!.
I should be able to feel if there is play in the U-Joints when I pull the shafts. If so, I guess I have some vice and sledge pounding work ahead!
I’ve used leaf spring perch wedges before, but wasn’t expecting to need them given how well engineered the OME Dakar packs seem to be. I’m also expecting the Dakar’s to settle quite a bit during the break-in period, which will help. I also removed one of the leafs to soften them given I don’t carry weight in the bed.
If the U-Joints, let’s hope it’s only 1 or 2 of them!
Last edited by Charles4x4; Jul 18, 2018 at 04:40 AM.
Good to know there is no Cartier Bearing like a Tacoma - if I had the truck, I would have just looked!.
I should be able to feel if there is play in the U-Joints when I pull the shafts. If so, I guess I have some vice and sledge pounding work ahead!
I’ve used leaf spring perch wedges before, but wasn’t expecting to need them given how well engineered the OME Dakar packs seem to be. I’m also expecting the Dakar’s to settle quite a bit during the break-in period, which will help. I also removed one of the leafs to soften them given I don’t carry weight in the bed.
If the U-Joints, let’s hope it’s only 1 or 2 of them!
your rear driveshaft only has 2 u-joints, so there is that going for you! shouldn't require any real pounding to change them out. a socket and small hammer to tap the cap out will suffice (a press works, too). the front driveshaft, and d-c joint, shouldn't come into play for normal driving. if the vibration is from the differential, you probably have bearing replacement in your future, rather than just seal replacement. that stake-nut doesn't come loose by itself.
your rear driveshaft only has 2 u-joints, so there is that going for you! shouldn't require any real pounding to change them out. a socket and small hammer to tap the cap out will suffice (a press works, too). the front driveshaft, and d-c joint, shouldn't come into play for normal driving. if the vibration is from the differential, you probably have bearing replacement in your future, rather than just seal replacement. that stake-nut doesn't come loose by itself.
Good to know. I had read some posts where others had front driveshaft issues causing it, but it seemed rare. Glad to hear the swap should be easier than I was thinking - I've read posts where a lot of pounding on a vice was required to get the caps out given how tight our driveshafts are. Here's a YouTube example - this guy seems to be a bit of a novice though and his wooden vice table is far from ideal:
You may have the U joints roller bearings binding in the caps due to lack of greasing over the years. After a slight angle change may have caused the condition show up in a vibraton.
You may have the U joints roller bearings binding in the caps due to lack of greasing over the years. After a slight angle change may have caused the condition show up in a vibraton.
Good thought. If so, would re-greasing them (assuming they are greasable) suffice or would they need to be replaced?
If you have the driveshaft out, you could grease them and try to work out the kinks, until you have smooth travel around it axis. You might have to install a grease zerk fitting if they don't have them. Next option would be to replace. I had a set on a 73 GMC pickup that that had slight vibration and this trick worked for over 2 years before finally replacing. Dirt and debris gets in the caps and without regular greasing, can pack up around the roller bearing and cause binding ie vibration
#5 on your list, that was my problem. I had a vibration when letting off the gas & when stepping on the gas at any speed over 45 MPH. Although I did not install a lift, I thought I would still share. The rear diff pinion nut ended up being loose because the stake gave out. I recommend you look at that, its easy to check it. I noticed you said you replaced the differential, may be related?
When I installed my OME springs it threw the pinion angle off. With a traditional driveshaft with a single joint at both ends, both the transmission output shaft and pinion shaft must be parallel. If they aren't you'll notice vibration. Here's a video I made to hopefully explain it and show how to fix it.
When I installed my OME springs it threw the pinion angle off. With a traditional driveshaft with a single joint at both ends, both the transmission output shaft and pinion shaft must be parallel. If they aren't you'll notice vibration
good point. in fact, if the flange faces are not parallel, the joint will follow an elliptical path instead of remaining in a single plane.
When I added the OME medium lift I developed an off acceleration whine when coasting. Much more noticeable in the higher gears and at speed. It went away when I depressed the clutch. To be thorough I checked pinion angles and they were so close as to not be the problem. U-joints were solid. I started to worry it was transmission/clutch related. I decided to do the ostrich and ignore it until I could do a better job diagnosing.
My shifter was a bit sloppy so I decided to install a new Marlin Crawler shifter bushing. My OEM was for all intents and purposes gone. After installation, all the off acceleration whine went away. My thinking on this is unless you clearly have identified some other component, this is a cheap and very simple thing to do. Unless someone has already replaced this bushing, I can guarantee the original is toast and so replacing this bushing is not wasted effort or just throwing parts at the problem. If it doesn't fix the whine, no problem you have better feeling shifter.
If I where you I would check for play in the U-joints, order the shifter bushing and check pinion angle. If U-joints feel fine I'd then grease the snot out of them (and the rest of the chassis) and go for a drive. If your pinion angle is off you can easily fix with shims. If all of these steps don't fix your problem then check your third member, pull the driveshaft/u-joints, etc. The way I try to work is do the simple/easy diagnostics first and then move to more involved things. If your pinion angle is off and you just replace the u-joints the noise may go away for a bit, but will end up thrashing your new u-joints over time.
#5 on your list, that was my problem. I had a vibration when letting off the gas & when stepping on the gas at any speed over 45 MPH. Although I did not install a lift, I thought I would still share. The rear diff pinion nut ended up being loose because the stake gave out. I recommend you look at that, its easy to check it. I noticed you said you replaced the differential, may be related?
Thanks, very helpful. I simply pulled the diff to reseal it (it had a gear oil leak). Everything looked solid that I saw and it didn't have any vibration before the lift was installed - which makes me think the new angles are causing it.
I'll do a full round of diagnosing once it's back. I'm hopeful it's not #5 for me
When I installed my OME springs it threw the pinion angle off. With a traditional driveshaft with a single joint at both ends, both the transmission output shaft and pinion shaft must be parallel. If they aren't you'll notice vibration. Here's a video I made to hopefully explain it and show how to fix it.
When I added the OME medium lift I developed and off acceleration whine when coasting. Much more noticeable in the higher gears and at speed. It went away when I depressed the clutch. To be thorough I checked pinion angles and they were so close as to not be the problem. U-joints were solid. I started to worry it was transmission/clutch related. I decided to do the ostrich and ignore it until I could do a better job diagnosing.
My shifter was a bit sloppy so I decided to install a new Marlin Crawler shifter bushing. My OEM was for all intents and purposes gone. After installation, all the off acceleration whine went away. My thinking on this is unless you clearly have identified some other component, this is a cheap and very simple thing to do. Unless someone has already replaced this bushing, I can guarantee the original is toast and so replacing this bushing is not wasted effort or just throwing parts at the problem. If it doesn't fix the whine, no problem you have better feeling shifter.
If I where you I would check for play in the U-joints, order the shifter bushing and check pinion angle. If U-joints feel fine I'd then grease the snot out of them (and the rest of the chassis) and go for a drive. If your pinion angle is off you can easily fix with shims. If all of these steps don't fix your problem then check your third member, pull the driveshaft/u-joints, etc. The way I try to work is do the simple/easy diagnostics first and then move to more involved things. If your pinion angle is off and you just replace the u-joints the noise may go away for a bit, but will end up thrashing your new u-joints over time.
I'll definitely check the U-Joints to see fi there is play and grease them if not. Note my Turbo is an Automatic (I should have said that earlier).
Update: I was fortunate. Once all the weight was back in the truck (which wasn't a ton - spare tire, interior parts, roll bar, seats, etc), the vibratoin went away by 95%. I may eventually see if I need a small shim at the rear leafs, but for now its hardly even noticeable. If it wasn't bad before, I probably wouldn't have ever even noticed it.
Jul 17, 2018 | 01:49 PM
