Vibration only in 4h at highway speeds.

Before anyone freaks out. I have looked all over this site for answers and have made a post without previous luck. So here I go again.

I have a growling pulsating vibration that can be heard and felt on the floor boards of the truck going between 110-120 km/hr, and sometimes at 80-100 km/hr while in 4h. I had the ecgs bushing installed before because I had the same vibration before but only in 2h, not in 4h. Since the bushing was installed there has been no issues in 2h. Now just in 4h. Anyone know what could be the issue here?

I'm running a revtek 3 inch lift level with 285 wheels -12 offset if that helps at all. I have a diff drop on the front that came with the revtek kit.


New information. The growling sound and vibration is constant between speeds of 110-120. As well with acceleration between those speeds.

BUT if I let off the gas the vibration and sound stops. Wheels have been balanced and zeroed out. Don't hear any constant grinding when turning.

The only time I hear some noise in 2h is when I'm crawling in traffic, 10km/hr or less. I feel the same vibration but it's not anywhere close to the extent when driving in 4h on the highway.

We had a crazy snow storm north of the border and most highways were snow covered with areas of ice. I feel the pulsating vibration even on snow covered roads.

I called ecgs and the said that they never tested there bushing at highway speeds.

What do you guys think the issue is?

 

take the diff drop out.

Sounds like its non proper angles between the two u joints of the front driveshaft that goes between the transfer case and front diff caused by the diff drop.

 

If I take the diff drop out won't that increase the angles of the cvs and cause them to have issues rubbing down the road.

 

I took the diff drop out, it did not fix the pulsating vibration. Any other ideas?

 

Look at the u-joints on the front driveshaft. Make sure all 4 bearing caps purge grease when lubed. Check the front diff oil level, and the transfer case oil level, and go from there.

And slow down. If traction is too poor for 2wd, it's too poor for those speeds.

 

The trucks a 2015 so I would hope all the fluids are up to par.

 

Hoping will get you nowhere. The diff was drained when the ECGS bushing was installed. It could be the front u joints too, make sure they're greased. There's a passenger side bearing in the diff too. Is it the same sound as the driver side bearing before the ECGS bushing? It's not a common problem, but it could still fail.

 

I'm not trying to be an ass, but there is no way to know your fluids are were they're "supposed to be" unless you check them.

 

How many miles are on the truck? Diff fluid levels aren't always "ok" just because it's a newer truck. My 2015 had low fluid in the rear diff when I changed the fluids at 30,000 gentle miles. Makes me think it came from the factory that way, I had no leaks etc.

 

50,000km on the truck. The dealer said everything was fine. But a tech even went with me for a test drive and felt the issue. After having the truck all day, they said the issue was from the tires needing to be rotated since they were wearing in the back more then the front. They did the rotation and still did not fix the issue. Any other input from anyone will be helpful.

 

There is no reason to be driving that fast in 4hi in a 4X4 vehicle, in an AWD vehicle it would be fine. If it is safe to drive over 25 mph or so 4X4 isn't helping you and may in fact give you less traction than you'd have in 2hi. Just because you can shift into 4X4 at those speeds doesn't make it a good idea. I can't recall for sure, but am thinking that 55 mph, which would be about 90 km/hr is the max recommended speed anyway for 4X4 operation.

 

might want to browse through this thread.

https://www.tacomaworld.com/threads...differential-bearing-vibration-thread.152173/

 

Has it always done this, or is it a new development?

 

@landphil he had it before in 2hi not 4, got ecgs bushing, now has it in 4hi, not sure how soon after it started tho

 

Yeah, I'm wondering about the balance of the front driveshaft, but if there was a time it would run smooth in 4wd at those speeds then that's probably not it.

Also, has the rear suspension been altered at all?

 

@landphil Revtek 3" kits come with AAL's unless he got the kit with the Blocks

 

Bullshit. All of it.

 

@Pigpen so you don't think its at all possible that you would have less traction in 4Hi, I can kind of see it, KIND OF. 4 wheels turning on a slippery surface vs just 2 kind of thing. Granted that in 4hi you have a better chance of recovering yourself lol

 

Well, either one alters the rear suspension and rear driveline angles. I'd suggest having the driveline angles measured and the calculations done to ensure the driveline working angles are within acceptable limits. I'm thinking poor rear driveline angles causing a mild torsional vibration combined with driveline tension in 4wd is what OP is feeling / hearing.

 

now I by no means have any knowledge of any of this, to me this is all a learning experience, but if it was a driveline angle would it not causes symptoms in 2hi as well as in 4hi. just seems odd that's its only in 4hi