Problems with 772.5 trans in a 1996 s320 - PeachParts Mercedes-Benz Forum

fredsegal · #1 02-17-2007, 09:51 PM

I think my transmission is going but I would like to hear from an expert as to what the real signs are.

1st seems fine, 2nd seems ok but 3rd and 4th will flare all the way to red line and sometimes don't catch at all but other times seem fine and the car be driven for 100 miles (or more) at highway speeds.

I first noticed the problem when I was driving at 65 or so in overdrive and would let off the accelerator the rpm's would drop down to 500-600. I have not changed the fluid because the mech said "if it's about to fail, changing the fluid will be the last straw. So don't change the fluid unless you are ready to shell out the $2700 for a rebuild"

Any help will be appreciated.

fredsegal · #2 02-17-2007, 09:56 PM

I think my transmission is going but I would like to hear from an expert as to what the real signs are.

1st seems fine, 2nd seems ok but 3rd and 4th will flare all the way to red line and sometimes don't catch at all but other times seem fine and the car be driven for 100 miles (or more) at highway speeds.

I first noticed the problem when I was driving at 65 or so in overdrive and would let off the accelerator the rpm's would drop down to 500-600. I have not changed the fluid because the mech said "if it's about to fail, changing the fluid will be the last straw. So don't change the fluid unless you are ready to shell out the $2700 for a rebuild"

Any help will be appreciated.

jhodg5ck · #3 02-18-2007, 10:28 AM

Quote:

Originally Posted by fredsegal

I think my transmission is going but I would like to hear from an expert as to what the real signs are.

1st seems fine, 2nd seems ok but 3rd and 4th will flare all the way to red line and sometimes don't catch at all but other times seem fine and the car be driven for 100 miles (or more) at highway speeds.

I first noticed the problem when I was driving at 65 or so in overdrive and would let off the accelerator the rpm's would drop down to 500-600. I have not changed the fluid because the mech said "if it's about to fail, changing the fluid will be the last straw. So don't change the fluid unless you are ready to shell out the $2700 for a rebuild"

Any help will be appreciated.

What about 5th? 5th is the 'gear' that eats itself first as it's essentially an undersized o/d unit strapped on the back of a 722.3

2700 for a .5 rebuild is fairly reasonable...and yes, I'd expect you are getting close. One thing I would do would be suck a quart of fluid out and add Lucas AT fix it in a bottle... It's bought more then it's fair share of miles on tired/failing transmissions.

As an aside, I leave all these .5's in 4th unless I'm cruising on the hwy...shifting into 5th around town does nothing but wear out already weak componentry.

Jonathan

whunter · #4 02-18-2007, 05:16 PM

Transmission:
http://www.peachparts.com/shopforum/showthread.php?t=142395

Have a great day.

mbdoc · #5 02-19-2007, 08:31 AM

I think that whoever said NOT to change the fluid is badly mistaken!

That should always be one of the first things that should be done..I would start by changing the fluid & filter. That trans will cost more than $2700 to rebuild correctly as the 5th gear overdrive unit goes for $1000 by itself.