Dirveline and accelerator issues on 93 FZJ80

[Nikofzj80]

Hi guys, looking for some advice on some minor issues on my 93 FZJ80 US Spec.
First of all, excuse my rather prehistoric English!

Land Cruiser has the Automatic transmission A442F.

DRIVELINE
Really don't know what the issue is (reason for this post), but this is what I am noticing:
- when accelerating from a full stop, sometimes I feel like the rear driveshaft makes a slight "bang". My logic tells me this can be wear in the drive shaft.
- when stopping from slow speeds, everything seems smooth, but when stopping from medium to high speeds, I can hear a "bang", but in this case, my senses feel it on the front of the car. The truck was at the shop this past week, they dismantled the front drive shaft, retightened and lube everything, and it got less aggressive, but the "bang" is still there.
- when accelerating steadily and suddenly I let go on the throttle, I sometimes hear that same "bang", also I feel it on the front.
- sometimes downshifting when stopping at a light, I notice the downshifts, but they are not perfect smooth. I understand it is a 30 year old transmission, with less technology and 210.00 miles of wear.

My main concern is whether it could be a driveshaft issue or a transmission issue.

ACCELERATOR / THROTTLE
I replaced both cables, throttle link and accelerator and it is sill hard to get a nice steady accelerator feel. I have to be very gentle to avoid a downshift when accelerating. This means when starting from a complete stop, I need to start rolling really slow to avoid going down to 1st (I believe) when pushing a bit hard.
I found a link in this forum to cable regulations standards, sent it to my mechanic and It is still not perfectly smooth. Don't know what else to do about it.

I used the search button, but didn't find anything similar to my driveline issue. maybe I searched for the wrong words, which has to do with my prehistoric English !

Thanks in advance for taking the time to read and for any input you guys might have!

Cheers

 

[Nikofzj80]

Hi guys any ideas?
Feel free to replace "bang" with "clank".
Still having this issue.
Cheers

 

[ajax1]

Post pics of the cables in the throttle. Pull each driveshaft and run in 2wd, with cdl locked. See which shaft is making the noise. If shaft prob worn splines. Both can be bought new from yota

 

[Nikofzj80]

Post pics of the cables in the throttle. Pull each driveshaft and run in 2wd, with cdl locked. See which shaft is making the noise. If shaft prob worn splines. Both can be bought new from yota

Will do that for sure.
So AT shouldn’t be a problem?
I have the spiders for both driveshafts. Splines are the same or something else?
Cheers

 

[OffRoadScott]

For your suspected bang/clanks in the drive line check for play in the u-joints, also when was the last time you greased the u-joints and the slip joints on the drive lines? Do not over grease your slip joints, you can cause them to hydrolock with too much grease.

As far as the transmission, check the level of transmission fluid. When was the last time you did a drain and fill of the transmission? Your transmission fluid level might be low and dirty. I would drain it and only refill the transmission with the same amount that came out during draining.

 

[Malleus]

Based solely on your description, I'd rule out the transmission. If it was the root cause, the direction of the sound wouldn't change.

Yes, the splines and the spiders are two different things. The ends of the propeller shafts have teeth on them; these are the splines. You can test for wear: hold the slip joint with one hand and the shaft with the other, at the points indicated by the arrows.

Try to twist them in opposite directions. There should be little to zero play between them. If you feel there is play, remove the shaft and inspect the teeth on the splined end. All should appear the same in form, to each other and along the length. Use the far end (away from the shaft end) as the basis for comparison. This end isn't engaged and so should be as cut at the factory. The teeth should be consistent in form from the inner end to the shaft end. If not, they should be replaced. If you get this far, take pictures and post them here if you have any doubts.

The clunk in the front could be related to drive flange spline wear. These are wear parts.

The outer ends of the front axle driveshafts are splined, similar to the propeller shafts between the transmission and axles.

The rear driveshafts aren't splined at both ends, as the front driveshafts are; they are only splined at the differential end. The outer end is bolted to the hub. It's unlikely that joint is the root cause of the clunk.

 

[Malleus]

My first effort would be to inspect the universal joints themselves, before working farther out. These are wear items (the splines on the propeller shafts are not, though they do wear, they are not designed to wear and be replaced as the drive flanges are, for example).

The check for the security of the bearings is the same as described for the propeller shaft. Hold the bearing on both sides of the cross shaft and twist in opposite directions using both hands. Sometimes it is helpful to raise the wheels connected to the propeller shafts of the ground, before performing this inspection. The driveline can "wind up", think of the entire line as a twisted rope, and when this condition exists, you may not find slack in a bearing.

This "twist" can also account for the change in direction/location of the sound you hear.

 

[Malleus]

To put your mind at ease concerning the transmission, check the color and smell of the fluid. It should be pink or red; the darker the color the older it is. If it's more black than red, change it. It should have a distinct smell but not smell burnt. If it does, change it.

You can use the engine and transmission to change the fluid nearly completely.

The transmission is connected to both the lower radiator and a cooler behind the grill. There are two hoses leading from and to the transmission. The upper one at the radiator is the outflow hose. If you pull this off the nipple and point it into a container and start the engine, the transmission will pump the fluid out.

There is a simple process for fluid exchange which will, as I said, nearly completely, safely, exchange all the transmission fluid. This can be done in less than 30 minutes, with no special tools. I have done this on my 80s and it makes a noticeable difference in shift feel.

 

[Nikofzj80]

For your suspected bang/clanks in the drive line check for play in the u-joints, also when was the last time you greased the u-joints and the slip joints on the drive lines? Do not over grease your slip joints, you can cause them to hydrolock with too much grease.

As far as the transmission, check the level of transmission fluid. When was the last time you did a drain and fill of the transmission? Your transmission fluid level might be low and dirty. I would drain it and only refill the transmission with the same amount that came out during draining.

Trans fluid was replaced like a year ago.
I have both front and rear U-joints that I need to replace. Will check the whole drive shafts.
Thanks!
Cheers

 

[Nikofzj80]

My first effort would be to inspect the universal joints themselves, before working farther out. These are wear items (the splines on the propeller shafts are not, though they do wear, they are not designed to wear and be replaced as the drive flanges are, for example).

The check for the security of the bearings is the same as described for the propeller shaft. Hold the bearing on both sides of the cross shaft and twist in opposite directions using both hands. Sometimes it is helpful to raise the wheels connected to the propeller shafts of the ground, before performing this inspection. The driveline can "wind up", think of the entire line as a twisted rope, and when this condition exists, you may not find slack in a bearing.

This "twist" can also account for the change in direction/location of the sound you hear.

Wow! Thanks for all the input.
The following where already replaced with brand new OEM ones.

Should I also replace the flanges?
Also did a knuckle rebuild with bearings and seals etc.
So now I will replace U-Joints and see what happens.
Maybe do a full drain on trans and check again.
Will keep you guys posted!
Cheers

 

[Malleus]

You can, of course, replace any components, but only the ones which are not functional should be replaced. Spiders (AKA universal joint bearings) can be replaced or regreased.

If the drive flange splines are tight, they are good.

 

[Kernal]

Does it feel like the transmission is slipping then catching suddenly,
or is it like a harsh (hard) shift between gears (going up or down through the gears)??

The A442 seems to have more problems with the shift solenoids than the later A343 transmission.

Translated to Spanish if that helps:

¿Sientes que la transmisión se desliza y luego se engancha repentinamente? ¿O es como un cambio brusco (brusco) entre marchas (subiendo o bajando las marchas)? La transmisión del A442 parece tener más problemas con los solenoides de cambio que la posterior transmisión del A343.

 

[Nikofzj80]

Does it feel like the transmission is slipping then catching suddenly,
or is it like a harsh (hard) shift between gears (going up or down through the gears)??

The A442 seems to have more problems with the shift solenoids than the later A343 transmission.

Translated to Spanish if that helps:

¿Sientes que la transmisión se desliza y luego se engancha repentinamente? ¿O es como un cambio brusco (brusco) entre marchas (subiendo o bajando las marchas)? La transmisión del A442 parece tener más problemas con los solenoides de cambio que la posterior transmisión del A343.

Not really.
It actually feels Like @Malleus said in an early message, like some kind of wind up, and when it releases I can hear the "clank". I can feel it on the front of the truck.

What I do feel is: When starting at a stop light, I am easy on the pedal, its ok, if I push it a little to hard, it will "kick down", which I thing its weird since I am just starting from 0. But I read somewhere that the truck starts in OD and if pushed it downticks to 1st? Is that correct?

Cheers

 

[Malleus]

That is incorrect. The A442F transmission always starts in 1st gear. The '96-'97 LX450, equipped with the A343F transmission, was programmed to start in OD and then shift to 1st gear, in order to make the shift feel softer.

There is a cable fitted to the throttle body which adjusts the shift pressure in the transmission, based on the throttle position. When the throttle is more open there is more pressure than when the throttle is more closed, resulting in a firmer, or harder you might say, shift. This is by design and is normal.

This is an extract from the 1994 Toyota Land Cruiser repair manual (AKA FSM). @SmokingRocks has generously provided a most excellent copy in the Resources section. If you have not already done so, you should download a copy for your use.