2001-2002-transmission summary

[eitankon]

Hello all,

You can find tons of materials in this forum , thanks to marvelous people and professionals that trying to help all of us who suffers from this trany (and other illnesses as well..)

Can anyone summaries this issue , to help others to understand better on how to cope with this nightmare ?

Ex:

1. The cause of failure of the Aisin trany 50-55 models 2001-2002 , is failure in the original valve body due to pure design.
2. If not treated right , it causes premature loss of the tray and needs overhaul.
3. Common symptoms are.......
a . b. .c.

4. The following treatment is used to prevent and to preserve the trany:
Oil change every 50,000 KM.
Use only Toyota type IV or with same values as this one.
etc...

5. Symptoms to show trany is damaged and needs to be rebuild:
a. 3 or more seconds delay from N to D
b. etc....

Of course all is under recommendations and people cannot obligate to these recommendations.

Kindly your thoughts.

Eitan

[howardc64]

Very tough summary to provide because

- Need statistics which require samples
- Each sample's repair cost = $$$
- Too many variables
- Too little observability inside the transmission

Probably why Volvo went with whole tranny replacement anytime they determined it was a tranny shifting problem.

Best to hear from mechanics that have some statistics. They generally seem to be relatively conservative on suggesting valvebody fixes. Since the fix isn't 100%, they don't want to eat the cost and have angry customers.

[JRL]

VERY bad to make general assumptions like this

[eitankon]

JRL - this is only a guidance , to assist others.

Each problem must be observed physically when car is under the mechanic's hand.

Howardc64 - I agree with you on the fact we need people who are in the business - mechanic's etc.

Volvo usually send the gear outside the garage , so I can understand why they don't mess with replacing parts.
Another thing is , that valve body causes at the premature damage to the mechanical part , they don't want to take chances.

My suggestion was only to try shorten the amount of time needed to search within so much info ...

Eitan

[davebeller]

Hi -

I just joined this forum the other day because I have tranny issues. After days and days of poring over this site, I stumbled upon a post from Astro14 (I think that's the name) that summed it up pretty well, and that seems to fit me and many others here perfectly. Here it is;


Here's the deal on the '01-'02 transmissions:
The biggest issue with the AW 55-50SN was valve bodies that wore quickly, resulting in low line pressure to operate the transmission. The low pressure led to damage to the internal components.
While they were under warranty, Volvo replaced the valve bodies...and in fact, in many other manufacturers, the same problem cropped up and there is a whole cottage industry to address the Aisin-Warner 55-50SN.
See here: http://www.sonnax.com/valve-body-layoutsVolvo added a bit of software that dropped the trans into neutral when stopped. When the gas pedal was pressed, the trans shifted into first. It ended up being very hard on the trans, particularly if the line pressure was low...it would slam into first and beat up the trans.
The common sequence of events is that the owner drives the car with some "small" glitches in how the trans works...but what is happening is the internal parts (bands, clutches...) are subject to excessive slip due to the low operating pressure. Most owners don't realize that if the trans takes 2 seconds to shift from reverse to drive, that something is seriously wrong...and that is the first sign of trouble...they just drive it for a few more years, putting up with the "quirks"...
By the time they bring it in for service, the soft parts in the trans are worn out and the transmission needs replacement.
Finally, while Volvo recommends changing the fluid every 52K in police or taxi service, they don't recommend changing it in regular service. So, most people don't...and the older fluid builds up with wear particles and lubricates less effectively.
The guts of this transmission live behind the 300HP V70R - and will last a long time if the trans is operating properly...So, it's not so much that they're junk - but that the valve body wear, poor software and lack of care killed them prematurely. If the valve body was replaced at the first sign of trouble, and the fluid was changed a few times - the trans will last a long time. Both my 2002 Volvos are running on the orginal transmissions.

Hope it helps!
Dave

[eitankon]

Indeed , good suggestions can be found in the forum.

Also the one from Astro14.