YATT - Car occasionally "misses" passing gear

[Armitage]

1993 Landcruiser, 3spd auto with OD, ~139K miles

Occasionally at freeway speeds when the auto transmission attempts to drop down to passing gear, it doesn't engage. By "doesn't engage" I mean the engine is freewheeling, and you have to get off the throttle ASAP. And of course, it ussually happens on the freeway with somebody on my bumper - so it's a bit disconcerting.

Anyway, if you get off the gas for a second, and then back on it will engage. I've taken to manually downshifting when it needs it, and this never misses.

Fluid level is fine. It always happens when the vehicle is hot, but it never really has an opportunity to happen cold. Any ideas?

 

[Heisenberg]

That sounds like a fairly serious internal transmission problem. I'd have a professional look at if it were me, as I'm far too chicken to mess around with the insides of an automatic tranny beyond fluid and filter changes.

 

[NutBucket]

I agree it could be a serious problem. A short term bandage might be an external trans cooler.

 

[Rastus]

Have the transmission fluid and filter changed. Sometimes this helps if there is sludge built up preventing proper fluid flow. Also your tranny will run cooler. If that doesn't do the trick, you probably will need expensive work.

 

[Armitage]

Originally posted by: Heisenberg
That sounds like a fairly serious internal transmission problem. I'd have a professional look at if it were me, as I'm far too chicken to mess around with the insides of an automatic tranny beyond fluid and filter changes.

Yep, I'm definitely not going in there myself. I know zilch about auto transmissions. I might try a fluid & filter change when the weather warms up and I have some time. I'd just like to have some idea what it might be so I don't get completely shafted if/when I take it to the shop.

It works fine with the manual downshift, and that's really not a hardship for me. I'd just like some peace of mind that it's not going to sh|t itself in the middle of a blizzard 40 miles from nowhere someday soon

 

[Armitage]

Originally posted by: NutBucket
I agree it could be a serious problem. A short term bandage might be an external trans cooler.

It already has one.

On another note - I've read somewhere that the transmission "flush" services offered are a Bad Idea. Something about forcing crappy dirty fluid the wrong way (ie. - not through the filter) through the tranny. Comment?

 

[Rastus]

Originally posted by: Armitage

Originally posted by: NutBucket
I agree it could be a serious problem. A short term bandage might be an external trans cooler.

It already has one.

On another note - I've read somewhere that the transmission "flush" services offered are a Bad Idea. Something about forcing crappy dirty fluid the wrong way (ie. - not through the filter) through the tranny. Comment?

Correct. A good place for transmission service is a Brake shop or Tire shop. They can drop the pan and replace the filter, which is more effective than a flush. I would never trust a lube tech at a Jiffy Lube to touch my tranny.

Transmission shops like AAMCO will rip you off every time you go in there if you let them. If there is a problem, let someone else troubleshoot, then go to AAMCO and get the work done.

 

[Armitage]

Anybody from the afternoon crowd?

 

[deadlyapp]

Clutch packs?
Edit: I'm mostly an MTX guy, but I know a *little* about ATX trannies in the 3000gt/stealth line of cars. I know that sometimes not engaging is due to the clutch packs being worn/w/e

 

[Armitage]

Originally posted by: deadlyapp
Clutch packs?
Edit: I'm mostly an MTX guy, but I know a *little* about ATX trannies in the 3000gt/stealth line of cars. I know that sometimes not engaging is due to the clutch packs being worn/w/e

Somebody else mentioned this to me, but I don't know what clutch packs are. I gather it's something different from a "rebuild"?

What exactly constitutes a transmission rebuild?

 

[NutBucket]

Originally posted by: Rastus

Originally posted by: Armitage

Originally posted by: NutBucket
I agree it could be a serious problem. A short term bandage might be an external trans cooler.

It already has one.

On another note - I've read somewhere that the transmission "flush" services offered are a Bad Idea. Something about forcing crappy dirty fluid the wrong way (ie. - not through the filter) through the tranny. Comment?

Correct. A good place for transmission service is a Brake shop or Tire shop. They can drop the pan and replace the filter, which is more effective than a flush. I would never trust a lube tech at a Jiffy Lube to touch my tranny.

Transmission shops like AAMCO will rip you off every time you go in there if you let them. If there is a problem, let someone else troubleshoot, then go to AAMCO and get the work done.

Actually, its not that the shop won't do it right. More accurately by flushing and dislodging all the sludge in the trans you can actually cause it to fail completely.

My understanding is if you kepp up with fluid/filter changes flushing is a good idea. If its been neglected its best not to flush it period.