So on my db1 I have a torque shudder most noticeable in second and third gear under acceleration and was looking for some fresh ideas. The car has new upper and lower balljoints, new axles, new intermediate shaft, new inner and outer tie rods, new wheel bearings and studs, pic select coilovers, revo upper control arms, poly bushings, full race traction bars, ys1 short geared transmission, exedy organic clutch, exedy flywheel, and a b20 block. I just redid the lower balljoints, the transmission, clutch, and flywheel. The only thing I can come up with is that it is caused by slop in the rack and pinion set, so I am going to tighten the rack and see what I can do or replace if necessary. This is not a new problem, but am looking for another perspective on where to look.
I have the same exact problem, also most noticeable in second and third. It seemed to decrease significantly after tightening the radius rods but its still there. I have a couple bad motor mounts too but I’ll be changing them out for brand new avid mounts next weekend.
I think it ends up being some combination of bad mounts, cheap axles, worn bushings / bearings, etc etc.
Cheap axles, unbalanced wheels, bad mounts. I went through this same problem over and over. If you are using any kind of parts store axles, that is your problem. Source a pair of OEMs and reboot them or get some from Raxles.com
Is there a way to know the axles are OEM? Like a stamping?
Oem axles have the rubber dampening ring in the middle of the shaft. Aftermarket axles (with the exception of Raxles) do not have this dampening ring.
I also have had great luck w/ Raxles. I did get one bad axle from them before, but the customer service has been great and they last a LONG time compared to parts store ones.
When you say that you “redid” the transmission, what exactly do you mean? Just a different trans for the car, or has it actually been rebuilt? It usually happens at lower speeds but a bad input shaft bearing can also cause a vibration under acceleration.
Sorry to jack but by input shaft bearing you mean the bearing in which the spline on the axle goes into? Also, if those bearing are bad could that be the cause of the inner “hub” of the axle having play even though it’s all the way in? Both my passenger and driver side axles have a little bit of play on the inner part if that makes sense. The part that goes into the trans and the intermediate shaft
I guess I wasn’t the most concise in my wording, The transmission is not new, It is a short geared ys1. It seems to be in good shape, but next year I am going to tear it down for a rebuild with an lsd and ls 5th gear. I ended up getting a set of new aftermarket axles since I was in a rush and was unable to get oems. It also has new innovative mounts that I put in with the transmission. I did adjust the rack guide a bit and that made a noticeable difference, but I couldn’t get the slop out without going to the point of being too tight. I ended up picking up a reman rack for now. The vibration is definitely much better then before, but I still can notice a shudder in lower rpms. I am going to adjust this rack, but again there is still a small amount of movement in the steering wheel, and it is definitely in the rack.
I also had the the front end aligned, the wheels balanced, and I put in ebc rotors and pads.