"shudder" in D and R in '91 740 wagon

Hi,
I just got a '91 740 wagon about a month ago. It has 167K on it. About two
weeks ago I noticed that when I am slowing down to stop it will "shudder"
for about 3-5 seconds when stopping at a stop sign or red light and in
Drive. Then it evens out and is no problem.Runs smoothly when driving at
normal speeds. It has also started doing it some when I shift in Reverse.
Mechanic said that a new transmission mount had been installed recently.
Just had transmission power flushed yesterday as well as fuel system.
Any suggestions? I am getting a 321 code(Regina system) but don't think that
is related.
Thanks for input.
JB

 

Sounds like you need to tune up the engine, the shudder is probably the
engine stumbling as the load increases at idle when you stop the car. I
don't know what that code means but find out and fix it before you chase
your tail.

 

Thanks James,
I did replace the plugs(with Volvo plugs) about a month ago but did not
replace cap,rotor, or wires(which now that I think about it are worn
looking). I did clean the throttle body and the car does not idle rough at
all.
JB

 

Did they do a thorough flush? What transmission fluid did they use?
Usually a shudder on decell just before stop is the lockup converter
clutch not releasing smoothly. OTOH a shudder in reverse when backing up
could be the front clutch slipping, or something as simple as a bad u-
joint.

Bob

 

Bob,
Interesting that you brought up the transmission fluid. It was an O'Reilly's
generic Dexron III.
The mechanic used a brand of cleaner,and conditioner that I can't remember.
He put the cleaner in before the flush. Flushed it with a machine(machine
was same brand as the cleaning agents) and then added a can of conditioner
after the flush. The old fluid was very dirty..
My mechanic owns an import shop. He is a Volvo certified mechanic with about
20 years experience. He uses mostly Volvo,Bosch and some other European
parts. The thing I do not understand is that he is of the opinion that all
motor oil and transmission fluid is the same. He believes that as long as
they meet certain requirements for a vehicle then one is as good as the
other. He did at one time use O'Reilly motor oil with a Volvo filter for
oil changes but now he buys Pennzoil in bulk and at least there is a name
brand motor oil.
Is a generic tranny fluid as good as a Pennzoil or Valvoline tranny fluid? I
don't know. I try to use name brands but I do trust my mechanic. He does
very good repair work.

James B

 

I've never heard of O'Reilly brand anything except for the guy on the
radio. Volvo lists some caveats deep in the literature mumbling about a
license number that should be stamped on the bulk drums or somwhere n
the case box for quart bottles that authenticates the formulation of the
fluid. If the license number exists it's pretty much the same as motor
oil meeting the SAE flavor of the year. If the old trans fluid was well
spent and there was some wear in the transmission friction parts then
the new fluid with a fresh friction modifier package can provoke a
different shift feel. I use Dextron III from Pennzoil or Quaker State
(same company now) and it indeed does have a license number on the
product, for what it's worth, but I seldom have any problems on a car
that was shifting fine to begin with.

Bob