A440 shudder (1 Viewer)

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Oct 27, 2021
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Location
Alaska
Have a 1988 hj61 12ht with the a440 that gets a bad shudder after the torque converter lockup happens. I have a parts fj62 with the a440 but am not sure if the I can just swap torque converter from the fj or if the 12ht has a different one and if the transmission from the 12ht would need to be rebuilt/ swapped also?
Trying to get as much advise and info as I can before spending a bunch of time and money on this.
 
Friction modifier additive like dr tranny sometimes fixes the shudder.
I second that. Had a shudder and used a tube of dr tranny which helped a lot.

@WildmanToo there is a member of this community, I cannot remember his name (but he's in Cali. and does work such as this for a living). He also recommended getting several bottles of the "Black" bottle tranny restorer - by the same maker as dr tranny. Then, go for a long drive so that the existing tranny fluid heats up properly. When back home, drain some fluid, then add a bottle of the "Black". Repeat three or four times, and make sure that the tranny fluid is topped up properly. This often cures, or at least extends the life of the torque converter in the A440.

If you search for "tranny shudder"/"torque converter shudder", or something close to that effect, you'll find the exact instructions in greater detail provided by the gent I noted above.
 
I'll give those a shot, do you recommend trying one before the other or both at the same time?

At work rn and won't be home for a week and a half so trying to get everything I need or might need ordered so it's waiting for me when I get home
 
do you recommend trying one before the other
I thought there was only one product for shudder? Old Nick might chime in with this ? I guess go with lubegard instant shudder fix I think it's called. The a440f holds about 15 litres all up, so use enough of it to suit this quantity of atf. Should be instructions on the tube. This stuff apparently actually works:) compared to other magic in a bottle cure all's
Definitely worth a shot. Let us know if it does work? I'm curious to know.
good luck

Forgot to add, I 'm not 100% but I think the 3fe torque converter has a slightly larger pilot than the diesel.
 
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I think what Nick is talking about is the lubegard highly friction modified atf supplement.

I'll get both of them but try the shudder fix first. Hoping this fixes it 🤞 and will update when I try it.

Bummer about the torque converters not able to be swapped. If this doesn't fix it the only one I'm seeing for the 12ht is the billet heavy duty tc for $1600 which seems expensive to me
 
Also if the tc keeps shuddering is it doing damage to the transmission or wearing out the tc faster or is it OK to keep driving it?
The couple times it did it was lower rpms with the lock up and to make it go away I just "made" it unlock accelerated to a higher speed and when it re lockedup at higher rpms didn't have the shudder. If that makes sense. Used that method to get home then parked it
 
Also if the tc keeps shuddering is it doing damage to the transmission or wearing out the tc faster
I often wondered this. Mine shudders every so often, but not enough to really bother me. Has done this for years without any apparent damage. I am going to try the lubegard soon. Been putting it off hoping it will fix itself. Can go for weeks without issue, then one day the shudder appears, then it's gone again:confused:
 
I'll give those a shot, do you recommend trying one before the other or both at the same time?

At work rn and won't be home for a week and a half so trying to get everything I need or might need ordered so it's waiting for me when I get home
Man, I’m sorry that I didn’t get back to you sooner.

I would go with the dr tranny first to see if it works (it comes in a small tube) simply because it’s the easiest step to take. If it helps or sorts out your shudder, excellent.

If it doesn’t - then go the lube guard route. Thank you for jogging my memory on its name!
 
I thought there was only one product for shudder? Old Nick might chime in with this ? I guess go with lubegard instant shudder fix I think it's called. The a440f holds about 15 litres all up, so use enough of it to suit this quantity of atf. Should be instructions on the tube. This stuff apparently actually works:) compared to other magic in a bottle cure all's
Definitely worth a shot. Let us know if it does work? I'm curious to know.
good luck

Forgot to add, I 'm not 100% but I think the 3fe torque converter has a slightly larger pilot than the diesel.
Here is the other product (made by the same folks who produce dr tranny).

 
Man, I’m sorry that I didn’t get back to you sooner.

I would go with the dr tranny first to see if it works (it comes in a small tube) simply because it’s the easiest step to take. If it helps or sorts out your shudder, excellent.

If it doesn’t - then go the lube guard route. Thank you for jogging my memory on its name!
All good, like I said not gonna be home to work on it for a bit
 
Well I've taken It for a couple drives and definitely better still a periodic shake but not anywhere near the shudder. I'm not sure if it is locking up when it warms up though, it used to go from 3rd, hit 4th for a second then lockup and stay in lockup unless I practically floor it. Now either it's not locking up anymore and just staying in 4th or actually using 4th and going in and out of lockup easier

How do other's a440s act?
 
That's exactly how it should work.
If the rpm's are approx 2200 @ 100kph it should be in lockup. IF it's 2400-2500 it's not locking.
It might need a longer / few more drives .
I can't remember, did you change / flush the atf?
Thanks for the update.
Ok good.
It's around 2000-2200 @ 60-70 mph
Will definitely be doing more and longer drives as she's my daily driver
I did a drain and refill, don't know if a flush is more involved than that
 
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I did a drain and change, don't know if a flush is more involved than that
If the old atf is really bad/burnt it's always better to get it all out. However 3 or 4 drain and changes over a week or so is just as good. Best to buy 20 litre drum , a lot cheaper. That's what I do .

**If you do the multi drain and change you will need to add the dr tranny again unless the new atf fixes the shudder.
 
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If the old atf is really bad/burnt it's always better to get it all out. However 3 or 4 drain and changes over a week or so is just as good. Best to buy 20 litre drum , a lot cheaper. That's what I do .

**If you do the multi drain and change you will need to add the dr tranny again unless the new atf fixes the shudder.
The old doesn't look too bad but I will do a couple more drain and refills when it gets warmer, filling thru the dipstick tube takes forever when it's -10 F
 
Synthetic atf is a good idea. Copes with heat better. I've heard anecdotes of synthetic curing shudder too. I Probably should have mentioned this earlier:notworthy:
I didn't know about it curing the shudder, I've heard since synthetic is thinner it'll find any leaks that are there. I didn't want to grenade my transmission if it did leak, I didn't notice and it ran out of fluid
 
Synth is claimed to maintain viscosity better over wider temp ranges. Mineral I assume gets thinner [as thin as synth? not sure] with heat. My a440 is due for a change of atf. It has mineral ATM. I'm going to do a few drain and fills with fully synth soon. AFAIK there is no issues mixing synth with mineral. I will report back if my intermittent shudder completely gets cured .
 
The old doesn't look too bad but I will do a couple more drain and refills when it gets warmer, filling thru the dipstick tube takes forever when it's -10 F
To add to what @pithicus said (which I think is spot on), let your truck warm up properly before driving it, especially when the ambient temp is cold, so that your fluids all have time to warm and circulate.

It could simply be an old wive’s tale, but it can’t hurt.

When I used to ride/own a Ducati, I never put it in gear or opened the throttle until the temp registered above “L” (120 on my moto). Never got a flaking rocker (with an engine notorious for that defect) 😉
 

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