Clutch Bump on start and engine brake

[imgfx]

Hi all.
Just got my camel back on the road! 1995 SR5 4wd 155k.

My mechanic said the front CVs were tight, so if they are tight, what would cause what I would otherwise think is a weak CV?
Feels like slack in the front end, although that is tight as well. He could be wrong.

My thoughts are worn motor mounts, CVs, or transmission. One mitigating factor is the the car was mostly pulled behind a motorhome for the majority of those miles. Otherwise, it is pristine with a totally unworn interior!

The front seats had TWO seat covers over the original seats. The spare still had paint on the outside tread. I have having the camel detailed today and will post some photos once she gets the grimy mechanic prints off her white paint.

Back to the topic... what should I have checked which would cause a slackness, clutch slap, cv jerk, etc?

Mike
Atlanta, Georgia

[dlb]

hi mike. everyone has had their own experiences with this problem but i have twice found that worn strut mounts were the cause of a clunk on clutch engagement when starting from a stop, as well as some shifts between gears, both shifting up and down. to adequately check them you must remove them: first remove the steering knuckle, then undo the three nuts at the top of the strut in the engine bay. once you have the strut out you can easily tell if the mounts are worn because they should only spin—if they wobble from side to side they are worn out and should be replaced. you need a spring compressor to do this, but be extremely careful. when you use the compressor on the spring, there is a ton of force just waiting to knock your face off of your head. spring compressors look like this.



again, i found this to be the cause of my mystery clunk, long after i replaced the engine and trans mounts, clutch, ball joints, inner and outer tie rods, control arm bushings, sway bar bushings, etc. but others here have found otherwise. best thing is to thoroughly check all the suspected components yourself so you know you're not doing any unnecessary and expensive work.

[Petros]

you have not really described in detail the behavior at all, but rather made guesses at what it could be. If you want us to help you, you need to tell us exactly how it is behaving.

There are lots of things that can cause a loose feeling, but short of telling you to check it all out yourself, we need more info to narrow it down. Could be ball joints, tie-rod ends, anti-sway bar end mounts (where it goes into the lower arm). We need more information: what it does exactly, when does it happen, noises, accelartion, turning left or right, braking, down shift, up shifting, or what?

[dlb]

i thought 'clutch bump on start and engine brake' in the subject line and then 'slackness, clutch slap, cv jerk' in the post covered what happens, when, and what it sounds and feels like.

[Petros]

I saw that and my first thought was I not sure what is meant by "clutch bump", I have never heard a clunk described as a bump, there is a term to "bump start" an engine using the clutch with a rolling car, but it is clear that not what he was talking about. Does the car jerk, along with a clunk, on acceleration and deceleration? Or at other times too. I just want a clarification of when it happens and what it feels like.

If indeed there is a clunk and jerk when he accelerates and decelerates, than there are a few things that can cause that: bad engine mounts (front or rear), bad rubber bushings in the anti-sway bar, loose suspension parts. CV axles do not normally behave that way, they get clunky in accelerating in turns when they wear, unless really badly worn (but than the problem is very obvious).

[imgfx]

I have had two sets of mechanics assure me everything visible is tight and in order, so that leaves the worn strut mounts.
I want to replace the struts anyway, because the shocks really feel womby and bouncy. Thanks everyone for the input!

Today I drove the "camel" 150 miles with no issues. Just trying to get a feel for what to replace/renew. I will continue in another thread.

[dlb]

imgfx, when you do your front end work, make sure that you or your mechanic also remove and check the front sway bar. even though the bushings can look good, the hidden parts of the bar that go through the lower control arm are notorious for rusting out. it is not uncommon to need to replace the metal collar that slide over this portion of the bar and the bushings as well. here is a thread on it in case you do the job yourself.

https://tercel4wd.com/forums/viewtopic.php?f=7&t=7481

regarding bouncy, mushy handling, you should also check to make sure your tires are fully inflated to 35 PSI when cold and that the panhard arm is still attached. this is the big thick bar that is mounted on the rear left part of the rear axle and goes up to the frame of the car on the right. i drove my last tercel home after buying it and thought the handling seemed really sloppy. got home and crawled underneath and found the panhard arm mount had been ripped right off of the rear axle! this is a huge deal since the panhard arm's job is to keep the rear axle in place. without it, the axle could go sliding out from under the car. real bad.

[imgfx]

The struts were put in, still have what feels like an engine mount bump, so I acquired engine and transmission mounts. The transmission started making really ugly sounds so now I am told I need a transmission. The camel has developed, camel-toe. She is getting expensive!

So I am sourcing a tranny to fix my camel toe, any suggestions? 4wd 1985 sr5.

[Petros]

Make sure it is really the trans, have you ever check/changed gear oil in the trans? If not you might drain it and see if there is metal particles or even gear parts in it. If so you will likely need a trans soon. if the gear oil is clean of metal flakes or chunks, you might try and trans flush with half and half ATF and gear oil, drive it for a few days and than drain it and fill with regular gear oil. Make sure you get a full 4 quarts in it (follow the procedure in the repair guides section).

Sometimes when the bearings get worn and sloppy the main gear shaft will shift back and fourth, causing a clunk, and even can pop it out of gear and you accelerate hard. if the sloppiness gets bad enough it will cause the gears to miss-align and parts start breaking off. when that happens lots of internal damage occurs the it may not be rebuildable. If you get it before parts start breaking it usually can be rebuilt.

If there are metal parts in the bottom of the trans, or stuck to the magnet on the drain plug, do not waste any money on putting fresh gear oil in it. Just pull it and start looking for a replacement transmission. Good luck in located another transmission, they are around but getting harder to find. All are the same age, some will last 300k-400k miles if treated nice and gear oil is changed every other year (every 30k miles), but some get bundled up in only 150k miles. Rebuild kits are still available but it is a big job and requires special pullers and clip pliers, and the kit costs as much as a good used transmission. Expect to pay $250 to $350 for a good trans. You will need to get a trans-axle assembly from an '85-88 Tercel4wd so the ring and pinion ratio matches the rear diff. The '83-84 has a different ring and pinion gear ratio and can be used if you either swap out the rear diff assembly to get the early gear ratio, or swap out the front diff assembly out of your existing trans (presuming it is still good and not trashed by ingesting gear cluster parts).

Drain the gear oil and let us know what you find. Also, catch it all in a fairly clean container and see how much comes out. If less than about 3 quarts, the trans was lubrication starved and that is what caused the bearing wear and damage.


Good luck.

[The Professor]

imgfx, did you ever figure out exactly what was wrong?

I am also having this bump/jerk when in gear during clutch re-engagement, as well as during engine braking right when I let off the throttle.

To me, this should be an easy to identify problem, but in my research it sounds like it could be anything from worn out strut top mounts, to engine/trans mounts, to the clutch itself.

Each of these parts should be making different noises and have different symptoms. It seems like there isn't enough consensus on what actually causes this phenomina.