Thread: auto got hot, is it now wrecked?

Originally Posted by 87County

Sounds like you've got it under control.

One more, or even two more, fluid changes will reduce the remaining proportion of old fluid. I wouldn't wait too long to do this.

I think about a week should be OK before the next fluid change.

Muddymatt,


Get the wife to tow the horses in 3rd and 3rd lockup. It will prevent excessive heat and less strain on the tranny.

Good save hopefully! I just did my trans fluid and filter. Very dirty but no bits in the filter. The crud trapped in the gauze on yours would have alarmed me too...
I notice since the service my tc locks up faster and cleaner

Pippin, how do you "lock up" third?

My interpretation of the story described, is that towing horses places excessive strain on the torque converter. Over a period of time there is excessive slippage which generates heat. Up to a point, a clean cooling system accommodates this extra heat. Eventually, overheating occurs, damaging the ATF and any other heat sensitive components. Provided the situation is promptly recognised, no other damage will occur, but the torque converter is still "kangaroo/edward". I'd stop giving the horses a lift (let'm walk) and use the gearbox more gently.

My understanding of this may be a total crock, and I'd appreciate hearing why.

Bob

Hi Roberto,
With the trany in third the TC will lock up at 80Ks and stay locked right down to about 60. It's a great way to tow or drive up steep long hills. The engine revs at it's optimum of 2500 at 80Ks and you get all the advantages with engine breaking down to 60 and effortless response on gradients with no wear on the TC and no extra heat generated, you can also smoothly change to Drive if conditions warrant it. It is one of the least known features of the Auto that is ideal for towing horses and vans.

I agree with the idea of towing in locked 3rd and I do it all the time with my 1tonne camper.
Just a detail.
The trans locks in third at 70KMh and in 4th at 80 Kmh, so when you are coming to a big hill a quick shift back to 3rd at over 70Kmh will see it lock in a second or two, and you can see it on the tachometer.
You can also use it for engine braking and it will stay locked down to 60Kmh unless you floor it.
Unfortunately it looks to be pretty late in the day for your transmission.
Regards Philip A

PhillipA,

Mine locks in third a little above 70Ks, but interestingly in the owners handbook there is no mention of TC lock up at all and thus no mention of how it can be used in third with only little mention of heat generation and driving techniques for towing.

Update.

Not good news
We did the same trip again today, 350k round trip and using third was better but there is still a judder on tc lock and unlock. It's magnified in 4th but still present in 3rd. Worse on tc unlock.

So it looks like it's stuffed.

My options are....

Take it to auto box shop for pull and rebuild. $$$$$
Buy s/h replacement unit from wrecker and fit. Less $$$$
Buy s/h replacement unit, strip and overhaul and then fit. Middle $$$$

If I go the last route, what mods do you recommend? Bigger t/c? Thicker flex plate?

I will be stage 2 Jose chipping it eventually and I have read about lower stall speed converters. Has anyone got first hand experience of them? It will be primarily a tow wagon until we get a horse truck then it will be my off road truck.

Lastly, if I'm going to all this bother I may as well swap out my non cdl lt230 for a cdl equipped unit and give that a birthday too!

Ashcroft has all the bits to overhaul both units, is a strip and rebuild of a ZF4HP22 a job only for a auto box specialist or can it be done at home?