khany2002

I've got an '86 4Runner (22RE, auto, bone stock). About 80,000 miles on it.

It's had a really annoying issue which has gotten progressively worse over the past year or so.

When shifting from park to reverse, or from reverse to drive, the whole vehicle jerks and the gear engagement is very harsh.

When in drive, gear shifting is equally harsh, unless you really baby the throttle, then shifts are somewhat smooth. I've just become used to letting up on the throttle before shifts, so I don't get the jerk (letting it shift around 1800 rpm as opposed to 2200 - 2400 rpm). This is the only problem with the vehicle, though -- transmission fluid, diff fluids and transfer case fluids are in perfect shape (I changed all fluids this summer, and the old fluids were in good shape), and the truck runs perfectly otherwise. The jerk happens whether the front hubs are locked or not, whether in 4WD or not.

My family has had this truck since new, and it's never been taken off-road even once, and maintenance has been kept up on it since day 1, so abuse or improper care is not a concern. The worst the truck has seen is towing a very overloaded trailer (say about 1500 - 2000 lbs) about 5 miles at speeds of no more than about 40 mph. I didn't notice any damage after this, though.

If you guys have any ideas what this could be, I'd really appreciate your input -- I don't have too much of an idea where to begin looking -- I'm suspecting something is just sitting loose, and getting looser the longer I leave it.

Thanks!
khany2002

dbcx

80k wow its not even broke in good. U-joints maybe? Did you change the transmission filter also?

khany2002

I've lubed the U-joints pretty much every year, although I think the caps on the U-joints are getting on (when I pump grease in there, you can hear the old grease spurting out from the splines). They still work though, as I can take the vehicle up to about 95 - 100 mph without any odd vibrations or noises. I'm told that if the u-joints were going out, I would notice vibration at higher speeds.

I dropped the front transmission pan when doing a tranny flush this summer, but wasn't able to get the pan clear of the front torsion bar, so I just sprayed the filter with brake cleaner, mopped up whatever came out with a cloth, cleaned all the magnets in the pan, and put everything back together. The second pan (a bit more rearward) was not dropped at this time. The fluid in it was still in good shape though, so I don't suspect its filter would be clogged.

rev. chuck

my 86 does the same thing but just when putting it in gear not when driving. and it been badly abused and worked on by idiots.

ill be interested in finding out whats doing this well i suspect mine is timed a little too high causing a higher rpm when engaging gear then what it should be

but that shouldnt cause the problem while driving bad mounts perhaps

khany2002

I'll check the mounts in a few days time; the truck is going to be coming in to the garage in a few days as I'm not going to be driving it in the winter. I'll give the mounts a once over when I do -- I don't notice any shaking of the engine, which I figured was a symptom of a broken / loose engine mount.

As well, I figured the engine mounts were designed to support the whole engine when offroading and all -- mine must be weak as hell if they can't stay tight just driving down the road!

Thanks guys!

abecedarian

what type of trans fluid have you been using? brand, rating, etc.

Tubbyfatty

My old 98 chevy lumina did this, but that was from a torque converter going out.

khany2002

Before this year, the truck was getting the regular generic-brand ATF, but only had about 3000 - 5000 kms put on it per year. Change intervals were about every 3 - 4 years I'd say.

This summer, the fluid was flushed and changed to Amsoil full synthetic.

The jerk isn't so hard that you think something is going to break immediately -- it's more a feeling almost of something binding a little bit, then engaging properly (while driving). It's much more pronounced if you use 4-low -- it will run up to say 3000 rpm, then, even with you babying the throttle, the whole vehicle will sort of buck, then shift into the next gear. Either way, it runs perfectly up to redline -- it's just the shift that's harsh.

The one where you shift from park to reverse isn't a BANG like I've experienced in some old Dodge trucks -- but it's definitely something I'd rather not be there!

Since the vehicle will be stored / driven very little for the next 4 - 5 months, I figured it would be a perfect time to fix whatever could be wrong!

abecedarian

what I was getting at was the type of fluid- Dexron II/III/IV, Mercon, Type F, etc.

sound's like you're getting hard shifts which could be caused by the wrong type of fluid.

abecedarian

what I mean is that the wrong fluid can cause the clutches in the trans to grip prematurely / not slip enough / grab and this would cause a hard/sudden shift to the next gear.

please don't assume I'm correct though. It could be a warn mount on either the trans or the engine exaggerating the effect when the trans shifts gears.

khany2002

Hey guys,

Sorry for the late response -- been really busy with exams and all!

The transfer case and transmission both are currently filled with Amsoil universal synthetic ATF (the one you can buy from the store). It was all put in this summer.

Before then, it always ran the basic in-house Canadian Tire Motomaster ATF fluid, which was supposed to meet the needs of the transmission. Since the vehicle did virtually no towing, and was never driven hard, that's all that was used.

Here's a picture of the bottle for reference.

As I'd said before, the fluid was always changed with very low mileage on it, and was still red when it was drained.

One thing which occurred to me was that about 5 or 6 years ago, my dad was driving my mom to the hospital in a severe snowstorm, and, in 4WD, made a U-turn. I was in the truck, and it was shaking / bucking quite a bit (I could feel the driveline bind), but, at the time, there didn't seem to be any noticeable damage. I'm not sure what I'd check that would've gotten stressed at that point (weak points).

Today, I had a little bit of free time, so I checked the driveshaft for any slop / freeplay. Sitting in park, there was no freeplay whatsoever in the rear driveshaft. With the wheels chocked and the transmission in neutral, there was around 5 degrees of freeplay in the shaft. This seemed to come from the transfer case, and there was a little bit of a click as the shaft rotated. I checked for play in the u-joints, and there seemed to be none.

With the vehicle running, I got underneath the truck, and had a helper shift between reverse and drive. I noticed that the driveshaft turned about 10 - 15 degrees between reverse and drive -- is this normal?

The shock feels like it's coming from the driveshaft area, and I'm suspecting the slip yoke, although it's always been greased, from my research, the ends of the shaft can get rough edges from wear, and, when the yoke is loaded and unloaded with power in a relatively short timespan (e.g. during shifts), that's where the shock comes into play.

As always, any thoughts / opinions are always appreciated -- I'm thinking of taking the truck down to my local Toyota dealership once I finish exams, and having the service tech manager do a simple road test with me to see if he can offer some insight.

Thanks guys!