Transmission issues/rebuilding the A45

[NEC]

I just recently started having transmission issues. After warming up it tends to overshoot its normal shift points during acceleration. Also, it wants to down-shift and over-rev rather than maintain speed on the highway. This is Waaay more than the throttle valve adjustment issue. It feels like the governor. It has also started in 2nd from a dead stop a couple of times. I had to really gas it to get it to kick down into 1st. I have checked the fluid but not the line pressure. Does this sound like valve body issues? I have rebuilt a few automatic transmissions in the past with success but don't consider myself an expert on how they work. I would love for someone to tell me this is a common problem with an easy fix.

[NEC]

I did a bit more driving today and I have isolated the problem to 3rd gear. When accelerating and shifting from 2nd to 3rd, the trans wants to keep slipping, and very slowly drops the rpms as 3rd gear attempts to grab. OD still works fine, but when it downshifts on acceleration it slips through 3rd and goes right to 2nd gear. These symptoms are always noticeable but i have had 3rd gear work as it should intermittently during my test drives. I still have the problem with starting in 2nd gear from a dead stop. I gas it hard and it will eventually bang into 1st gear and accelerate from there.

[timsrv]

I'm not a transmission expert either, but the slipping part isn't good. It sounds like you may have a clutch pack that's getting worn. Have you smelled the ATF to see if it smells burnt? A burnt smell accompanied by a brownish tint is a sure sign the transmission is failing, but not all failed transmission exhibit this. How many miles are on it? These tend to go about 200k miles or so with normal driving. After that you're on borrowed time. I hope it's not that, but it doesn't sound too good. Tim

More comments on this subject HERE (http://www.toyotavantech.com/forum/showthread.php?210-87-4wd-auto-tranny-died-what-now)

[NEC]

I think I'll take apart the valve body first and inspect it. After that, I'll probably take on a whole rebuild as long as I don't have too much hard parts damage.

[theschnell]

My van was exhibiting some of the same symptoms, some different, but it eventually started slipping in all gears. I just changed the fluid and filter and drove it 50 miles home with no issues. If you haven't already, I would start with the filter, and then go from there.

[NEC]

I'm glad you got yours running. Mine isn't having problems with the filter. I think i have a sticky governor. Mine is a 4wd so getting to the governor requires tearing removing the xfer case. I think I'll hook up the hydraulic gauges and drive around a few days to confirm my suspicions before committing to the complete rebuild.

[theschnell]

I'm lucky mine was something so simple. Only time will tell if I'm ok. You obviously know a lot more about transmissions then I do. Good luck!

[NEC]

Well, I rebuilt my transmission today. The front clutch was completely toasted and the rear clutch pack didn't look much better. Everything else looked like new. It appears this transmission has been rebuilt before. The whole job took about a day, plus a few hours after work for the valve body. No special tools were required except a press to help removing the snap rings from the clutch pistons. I didn't take any pics except one of the valve body with all it's guts out on the table. It turns out I didn't need that picture for re-assembly. In all, I have about $300 into the rebuild. I will get it installed tomorrow and hopefully I will have some time till my next major part goes out. I have been hearing a whine from my rear axle.... good thing I have 4wd.