I've had a shake in the cab section of my truck for ever!!

I've checked every part in the front in end myself and replaced all the bushings, had it taken to places to check out and both shops said it was fine. I had alignment and new tires done.

So I figured I had bad u-joints... which I did.. but now both have been replaced and still i have a wobble.
I replaced the transmission mount a while back because it was done for when I first started diagnosing the problem. I also made sure the drive shaft had been balanced when the joints were changed.

So what could it be?!? It feels like my auto transmission is shaking.... but i dont even know where to start in diagnosing that?

also sometimes I will feel a slight "knock" or "clank" under strain or in a full lock turn... I keep imagining a worn bushing crushed to nothing, toward the back and the shaft is just barely knocking around...

i swear it feels like a bad u-joint up front but they're both brand new... and I took my driveshaft to a reputable place where ALL they DO is drive-shaft work..

I think between having a bad transmission mount and bad u-joints could have damaged my transmission in SOME way to be causing something like this..
The truck drives perfect and shifts perfect the only problem is this wobble.

 

tell us what the setup is on the truck... exact suspension setup. whats been done. is it the whole cab that wobbles/vibrates?

do you feel anything at your steering wheel? do you know a place that has a dyno you could throw it on and inspect the truck while rolling on the dyno to the specified speed you feel this movement to inspect it visually? this would be my next step.

 

slammed all the way with torsion at the moment but this was done recently trying to see if the wobble was shocks related..
4" blocks in the back I'm pretty sure they're tapered even though I have the regular cab and bed.

I dont feel really anything in the steering nor do I get any pulling in any direction.

But I'll see the hood shaking a bit and I bet my rear view mirror shaking.

Yeah running on a dyno would make sense but I dont have much access to that since Im on a budget :-/ I dont know who I would take this to that might specialize in something like this..

is there a bushing or barring or anything that is designed to be replaced in the transmission. Some kind of maintenance part that goes out at almost 200k...I do also always notice a drop of tranny fluid handing from the rear of the tranny. As in it doesnt really "leak" but fluid is obviously coming out lol... if that makes sense..theres no puddle under my truck and the level is always fine when I check it..

 

Maybe engine mounts are bad.At idle does it vibrate.Does it vibrate in neutral without the trans engaged.Does it vibrate in any particular gear or under any particular conditions.Try to narrow it down.

 

At what speed is this vibration! Is it all the time? Is it only when turning! Are u sure its not a bent rim or tire balance issue?

 

this may be unrelated but try this and swap your front wheels to the rear and front to back and see if this changes the frequency or origin of the vibration any.

im also gonna suspect the taper on the rear blocks could be a factor since at 4" ive never used any taper on them and had better results with controlling vibration. you can remove the rear blocks and take it for a quick drive to rule this out.

the drop of trans fluid could be normal wear, and not much to be related. the only other thing at this point would be the motor mounts as previously mentioned. check these areas out and get back to us.

 

Maybe just something we have to live with. I've been chasing the same gremlin for a couple years now, except mine's rear. I've swapped tires, rotated tires, checked driveshaft, u-joints, pulled rear axles, and it persists. Mine's a 5 speed, but does it clutch in or out. Decided just to live with it. I've stumped the best this town has to offer.
Good luck.

 

It's so subtle it's hard to find exactly when it triggers. But it does it pretty much in all gears. it gets a little worse the faster I go, but it doesnt effect my driving a bit...

It's taken me for ever just to narrow it down to being in the middle of the cab.. but really i see vibration in the whole truck so im not even sure. But Im REALLY starting to think that taper in the blocks has something to do with it....

before my toyota i had a slammed gmc sonoma but it was an extended cab so I remember NEEDING the taper so i wouldn't get vibrations in the shaft. I wonder if since my 88 yota is a regular size I should not have gotten the blocks with a taper. and now it's having a negative affect on my shaft alignment...

 

Try what SD said and just take out your blocks and drive it and see if it's still happening..

 

So I've been extremely busy with work and everything and still havent managed to take the day to figure out my dilema.. but the vibrating has gotten a lot better for some reason...so I kind of lowered on the priority list..

BUT I am still having transmission issues, where it's struggling to engage in drive and reverse. It started every morning here and there. Now every morning when I first start the truck, I put it in drive and wait a second to kick in...

sounds more like the torque converter to me... but im still looking around on craigs for a new tranny anyways... figured 200k is about time for a new trans.. before it breaks when I least expect it...

since my friends 92 with 160k just went through the hassle of replacing his tranny, it worry's me...

 

Maybe its time to start rounding up parts for a stock shift swap. Not sure if that suits your needs, but most of us prefer them on this type of truck after driving both.

That aside, it may be the rear tail shaft bearing and/or rear main seal of the trans. Having had bad u joints like you said it could have gotten wobbled a bit worse than usual. And now it finds a spot to clunk around. My carrier bearing is the same way.

If its no seeming to be getting worse, go ahead and focus on other issues. But don't totally forget about it. You'll be kicking yourself on the side of the road otherwise.

 

I think that's exactly whats wrong... the slight leak, the slight vibration toward the tail of the tranny.. and now this..

it's totally getting worse though -__- It went from never happening to now a regular thing.. i think it could drop in the next few months of year...
Its about 200k thats about the life of one of those trannys I'd think.. :-/

How difficult is the process in comparison to do a stick swap or just an exact auto donor?

I always drove stick but I didnt care because I wanted this specific truck.
I'm completely used to it now and pretty indifferent.. automatic makes it feel like a go kart

it's my daily so the truck cant be down for more than a couple days..

 

craigs or ebay another auto trans it takes about 4 hours if you've done this kind of work before. a manual is a straight forward swap but you have to have every bit of parts to do it and be prepared for a bit of frustration to get it just right. I prefer the auto myself cause I can blip the throttle though the gears