Auto shudders in reverse under load

[RAVXG Lurker Find all posts View Profile Close RAVXG]

Hi

I reversed my 1999 Prado V6 auto up my short slightly steep driveway, with my 250kg box trailer, and bugger me the thing shuddered twice or so . I have 201,000kms on it. It must be the 343etc?? transmission.

I stopped, continued up the drive in reverse and its fine. I tried it without the trailer, in reverse, and I had to give it a bit of boot to get it to shudder once again.

A third time a day later, and no shudder. Driving forward is fine.

About a year ago, it was a cold morning (around 5C), and I started her up, run it for 30sec (yes I know its not long enough!) and engaged reverse. Nothing. I then engaged Park again as I wondered what was going on and the auto clunked and shook the car. Felt like a delayed reaction to engaging reverse. Shook me too!...since then only the episode described above has gone on with the auto.

Now, the auto is what I would call a little slower to change up and down, and sometimes I feel a little minor clunk when approaching a stop and it changes down, but literally nothing going wrong in any major way.

I had the auto trannie oil/filter changed about three months ago, although may not have been a full flush as outlined by Ken Cairns in a post here(that is awesome Ken!), but the ATF is clean to look and touch. No smells and red colour. Plenty of it too. No delayed reaction to engagement in R or D on any mornings.

Anyone else experienced such issues? It is going in on Friday for a diagnosis at an specialist auto trannie place. I bet they will want to rebuild for $4K. I am thinking sell or trade as it may be the beginning of the end.

Any advice is appreciated,

RAVXG.

[RAVXG Lurker Find all posts View Profile Close RAVXG]

....for those following this, I had the trannie checked out by an auto trannie specialist. Ran the diagnosis machine on it and tested it cold and hot. Reckons 100% fine and can't fault the box. In fact, spoke well of the reliability of the 343 box since early 90's as used in Hilux's and Prados....but..picked up MAF sensor fault code. That's why it has been using too much fuel. Having said that, economy has now improved back to approx15l/100km around town. Will clean MAF anyway.
Cheers

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Yeah mate there a pretty strong box, there actually the same box behind the 80 series cruiser and there reliable as. I use to get the occasional shudder in reverse in my old petrol 90 under the same conditions you describe but not in my diesel 90 ?? go figure. I never worried about it and the commodore we had (bought new) shuddered from day one if reversing up hill with a load, again never worried about it either and never gave me any issues in 5 years of owning it.. Good you had it checked over and all come ok, and found an issue with the MAF sensor so will recoup your service bill in fuel over time....There a good strong vehicle the 90, I do love my 120 but the 90 was also a great 4wd. The diesel was a bit under powered and had head issues but still a great 4wd..Cheers Steve

[brissy Member Find all posts View Profile Close brissy]

had this exact problem with a Mitsubishi triton, ended up being 2 broken engine mounts, only in reverse as well must be the lower gearing

[brissy Member Find all posts View Profile Close brissy]

come to think of it right hand side mount was fully ripped probably the twisting torque lifting the motor in reverse, but opposite twisting torque in forward pushing the motor against the broken mount

[Ken in Cairns Junior Member Find all posts View Profile Close Ken in Cairns]

Thanks for the complements mate, glad you found it of some use

Can't say that mine shudders, even reversing the 2 Tonne boat, but not up a steep hill.
Could be a busted mount, easily checked, if it was a manual I would say clutch shudder, could be the reverse clutch pack in the auto, but if the auto man says it is OK it probably is .

Is a clutch pack in the limited slip diff as well, so it might be in the diff.
Not caused by the wheels spinning a bit ?? The rear end will be light going backwards, try it in 4x4 and see if it still shudders.
Worth a try anyway....

Let us know how you get on mate
Cheers
Ken