A343F reverse noise

Brian894X4 · 10-15-07, 01:16 AM

It's a '95 FZJ80 with the A343F, 93,000 miles. Recent tranny flush a few months ago.

What happens is when I put it into reverse and there's a load, such as trying to back up a hill or over something, the engine revs, the rig doesn't move and then a noise that sounds like metal grinding or slippage in the transmission occures. It's never a problem on the street or normal backing up. Works perfectly the rest of the time.

I've searched the threads and everything seems to come back to a TSB regarding some check valve or something on the 343F. Does anyone have any more details or the TSB itself that I could look at?

Referring to this thread, this sounds like my problem:
Transmission slips in reverse

One question I have is, if this is the problem, can I retrofit whatever changes need to be made to the checkvalve, oil rings, etc and stop this problem or is now too late? And does the fix really require removal and tear down of the tranny. Some threads seems to indicate that only the valve body needs to be removed and that the tranny can remain on the vehicle.

Finally, has anyone found that using 4L in reverses helps negate the problem at all?

Thanks much.

DanKunz · 10-15-07, 04:45 AM

FWIW, it sounds like you have garbage in your valve body preventing proper shifting (probably from the flush...don't do that!!).

If I recall correctly, you can access your solenoids and the valve body from below without dropping the tranny, but pretty sure that would suck for your back and your level of cleanliness.

Wait for others to confirm, but unless someone comes up with something magically unheard of I am pretty sure you have crap up in there and it isn't getting fluid to the right place at the right time, and some nasty metal on metal action is the result.

landtank · 10-15-07, 04:52 AM

I swapped my tranny out for this problem. There is a check valve change and also pressure plate change. At some point I posted the serial number break down for those trannys. Basically a late production 97 is the best choice. I contacted cruiserparts.net and was able to confirm that the tranny he had had the changes by using the serial numbers.

I'm leaving for a week of work annd if this thread is still active I'll try and post TSBs if I can find them

here is the link to the tranny serial number break down TSB

Brian894X4 · 10-15-07, 10:11 AM

Thanks Rick,

I guess what I'm wondering is if this is something that can be fixed without swapping transmissions. Perhaps with the tranny still in the vehicle, by doing some of these updates you mentioned.

Sounds like all the changes occured after 1995 and since I have one of the earlier 343F I get the big screw job. This sucks.

landtank · 10-15-07, 03:02 PM

some of the fixes require removing the tranny to do. Might as well replace it.

right now, good, used, and cheap '97 trannys are out there. You have the info to get one completely updated from the factory. I don't know your mechanical skillz but I opted to swap mine out. As time goes on and more people have issues and they become smarter about what to look for I think these cheap 97s are going to get real expensive.

But this is from a guy who did his HG as a PM before anyone else.

L8Shift · 10-15-07, 08:02 PM

Quote:

Originally Posted by Brian894X4

What happens is when I put it into reverse and there's a load, such as trying to back up a hill or over something, the engine revs, the rig doesn't move and then a noise that sounds like metal grinding or slippage in the transmission occures.

I back-up on a hill when I parallel park in front of the house.... I usually wait ~5 seconds in reverse before giving it any gas....

If I give it gas immediately after I go into reverse (on the hill), I get the chatter noise, and go no where.

CactusCruiser · 11-15-07, 02:45 PM

My tranny somehow didn't get the upgrades that have been mentioned or I have a different issue.

Shift the transfer case to low seems to take care of it though.

gray · 11-15-07, 03:19 PM

My early 1996 model had a similar problem, but it started after I had added some additives; I was looking for a crisper shift, but I got mush instead; and a violent shudder/slipping in reverse.

I immediately drained out what was in the pan, then as soon as I could, I flushed my tranny with two bottles of LUBEGARDs tranny flush/cleaner, and 16 quarts of Mobil 1 synthetic; problem solved. I think the LUBEGARD did the trick; it is a high quality, non-solvent based cleaner, not cheap either; $10 per 8 ounce bottle. I drove the vehicle with one bottle in the tranny for a day, then added the second bottle about 10minutes before the flush. Avoid the cheap bulk ATF most quick lube places use, unless your plan is to flush it again with good stuff; can't hurt; I flushed mine three times before it came out clean, the last time with the Mobil 1.

Key point; most places do not use enough ATF for a flush; you must use at least 14 quarts IMO. Two Toyota dealers, independantly, both used only 6 quarts to "flush" my tranny. I noticed the ATF was still a bit dirty after the second flush (15K miles after the first); the service writer did not know how much fluid was used, so I asked him to ask the mechanics; the answer; "we use 6 quarts on everything, they all take the same amount of fluid"

The flushing may not work for the original poster, but might be worth a try before you replace your tranny; particularly if you do not know what fluid or additives are in your tranny. Be sure to use a high quality Dexron type ATF; IME.

g

theyis · 11-15-07, 04:40 PM

So Rick,

Do you know what 97 model numbers have the latest updates or do all the 97s need the ball mentioned in the TSB?

Kyon

landtank · 11-15-07, 04:47 PM

TSB breakdown:

Starting with serial number 96JE-06161, the B3 brake return spring assembly and low coast modulator valve compression spring was updated.

Starting with 97AE-07106 the material of 3 O-rings where changed to help them seal better.

Then serial numbers 97H*-00001 thru 97K*-99999 need to have the check ball added to the valve body.

Look at your serial number and plug it into the serial ranges above.

IdahoDoug · 11-15-07, 08:47 PM

Rick,

Thanks for the #s. Where's the serial number - tranny or the build plate? If tranny - where is it located so I don't get my pajamas too dirty.....

DougM

landtank · 11-15-07, 08:49 PM

from memory it's on the PS near the back just above the oil pan seal. It's a little silver plate.

landtank · 11-15-07, 08:55 PM

here is a pic pulled off of here. You can see the tag behind the rear cooler connection

IdahoDoug · 11-15-07, 09:20 PM

Man, that's a devilishly difficult place - the rear shaft joint is right next to it and its loaded with crap. I tried wiping it clean and wore off a lot of blue paint but did not get it clean. You have to angle your hand up over the shaft and back down so.....I got some grease on my favorite SpongeBob footy jammies. In your picture there's a black plate slightly forward of the rear circled cooler nipple - are the #s off that worth anything? That rear plate's gonna take some ugly dripping and spraying of brake cleaner tomorrow.

DougM

Brian894X4 · 11-15-07, 09:59 PM

Quote:

Originally Posted by landtank

TSB breakdown:

Starting with serial number 96JE-06161, the B3 brake return spring assembly and low coast modulator valve compression spring was updated.

Starting with 97AE-07106 the material of 3 O-rings where changed to help them seal better.

Then serial numbers 97H*-00001 thru 97K*-99999 need to have the check ball added to the valve body.

Look at your serial number and plug it into the serial ranges above.

Just so I get this straight, all A343s prior to the 96JE-06161 have a poor quality brake return spring assembly and low coast modulator. (Does this affect reverse?)

And all A343s prior to 97AE-07106 have 3 low quality oil rings that may not seal properly. (Any idea how the O-rings might affect the reverse noise?)

The part I'm confused on is the last one. Are saying that ONLY A343s within that 97H through 97K serial range need the check ball added? If so, I assume this last one doesn't affect most 1995 and 1996 transmissions?

Thanks for posting this up again.

theyis · 11-15-07, 10:01 PM

Quote:

Originally Posted by landtank

TSB breakdown:

Starting with serial number 96JE-06161, the B3 brake return spring assembly and low coast modulator valve compression spring was updated.

Starting with 97AE-07106 the material of 3 O-rings where changed to help them seal better.

Then serial numbers 97H*-00001 thru 97K*-99999 need to have the check ball added to the valve body.

Look at your serial number and plug it into the serial ranges above.

Thanks Rick. I guess what I was asking was... Is there a series that doesn't require modification. You said you replaced yours with a 97 trans. I have a 97 and am wondering if mine is good to go. In reality I'm being lazy and don't want to get covered in grease at the moment like Doug is. I just want to keep my Spongebob jammies clean

.

Thanks,
Kyon

alaskacruiser · 11-15-07, 10:14 PM

Rick- does your list of serial numbers imply this:

The following trannies have all the upgrades (B3 brake return spring assembly, low coast modulator valve compression spring, O-rings) and require no valve body modification:

97AE-07106 through 97G*-99999
and
97L*-00001 through End of production run

Please let us know if this is accurate. Thanks!

Bear80 · 11-15-07, 11:04 PM

Can the check ball and spring be added to the valve body without pulling the whole tranny?

landtank · 11-16-07, 04:10 AM

Quote:

Originally Posted by landtank

Starting with serial number 96JE-06161, the B3 brake return spring assembly and low coast modulator valve compression spring was updated.

Any transmission built prior to S# 96JE-06161 has nothing but after that it has the above mentioned updates.

Quote:

Originally Posted by landtank

Starting with 97AE-07106 the material of 3 O-rings where changed to help them seal better.

Any transmission starting with S# 97AE-07106 and on has the first set of updates as well as these three o-rings being updated.

Quote:

Originally Posted by landtank

Then serial numbers 97H*-00001 thru 97K*-99999 need to have the check ball added to the valve body.

Then I suspect that some other parts where changed starting with S# 97H*-00001, but a TSB wasn't generated for those changes, which created the need for the check ball to be added. This last update is actually for a noise shifting OUT of reverse, not shifting into reverse as the two previous ones are.

The ball can be added with the tranny in place. It goes into the valve body itself. The tranny I got is one of the ones that needs this ball and I have heard the noise coming out of reverse a few times.

theyis · 11-16-07, 08:31 AM

So is this a destructive type of issue? What I mean is if I just wait a few seconds after I shift into reverse for the fluid to make its way through the passages correctly is that good enough or is there going to be damage if the updates aren't installed?

Kyon