not always going into overdrive - PeachParts Mercedes-Benz Forum

Bigmon · #1 12-25-2006, 07:02 PM

I have a 99 E320 with 185k. Last week when I was on the freeway I noticed it took several miles before the car shifted into overdrive. It happened 2 of the 3 times I got on the freeway. The 2 times it did it the temp. outside was about 50 degrees. The 1 time it went right into overdrive it was about 70 degrees.

In Feb 2006 when I got the oil changed they said the shift bushings were gone. I didn't fix them because they said it was not critical to fix them right away. Any thoughts?

Hatterasguy · #2 12-25-2006, 07:30 PM

Mercedes don't have overdrive. Your car isn't shifting into 5th gear.

C32AMG · #3 12-25-2006, 11:32 PM

You have to check for fault code in all modules.

wbrian63 · #4 12-26-2006, 09:00 AM

The definition of overdrive is when the output turns more than 1 revolution for every revolution of input. Mercedes do indeed have overdrive - 5th gear in my car is (92 300SE) is 1 revolution of the transmission output shaft to every (I think) .70 revolutions of the crankshaft.

Overdrive can be in any gear (the latest Corvette has OD in 5th and 6th gear).

Far as I know, any MB car that has a 5 or 6-spd automatic has OD in the top-most gear.

The shifter bushings can make a big difference, especially if the shifter is vague enough (due to the missing bushings) to not properly set the shift-position switch to tell the transmission that top-gear has been selected via the shifter. Try downshifting to 4th and then upshifting to 5th and see if that helps.

I'd get the bushings replaced - and pulling codes is definitely good advice.

Bigmon · #5 12-26-2006, 12:18 PM

Thanks for the the tips. The check engine light does come on once in a while, but goes out after a day or two. I'll check the codes. I'll see about the bushings too.

Johnhef · #6 12-26-2006, 12:49 PM

The trans control maodule can set off the check engine light, definte good advice to check the faults in both modules.

Hatterasguy · #7 12-26-2006, 02:11 PM

Quote:

Originally Posted by wbrian63

The definition of overdrive is when the output turns more than 1 revolution for every revolution of input. Mercedes do indeed have overdrive - 5th gear in my car is (92 300SE) is 1 revolution of the transmission output shaft to every (I think) .70 revolutions of the crankshaft.

Overdrive can be in any gear (the latest Corvette has OD in 5th and 6th gear).

Far as I know, any MB car that has a 5 or 6-spd automatic has OD in the top-most gear.

The shifter bushings can make a big difference, especially if the shifter is vague enough (due to the missing bushings) to not properly set the shift-position switch to tell the transmission that top-gear has been selected via the shifter. Try downshifting to 4th and then upshifting to 5th and see if that helps.

I'd get the bushings replaced - and pulling codes is definitely good advice.

Thanks for clearing that up. I was refering to OD in the American and to a certain extend Japanese car sense. Ie it operates as a 3spd and won't shift into "OD" unless you push a butten or move the gear lever. But you can't use it around town because it lugs the engine down, or in Toyota's case overheats the trans. MB's use a straight 5spd, 4spd whatever, put it in drive and it does its thing.

wbrian63 · #8 12-26-2006, 02:45 PM

Hatterasguy - OK - gotcha.

I'd always heard about that issue with American cars, too, but I've largely ignored it on the cars that I've had with no negative effect. The biggest problem I've seen, and you noted it in your reply, was the lugging effect from being in too high a gear at too low a speed.

My '92 300SE doesn't shift to 5th until 50mph, which prevents that lugging problem, but I'm having a time getting used to that high shift point vs my '93 Lincoln Mark VIII which shifts to 4th (OD) at about 38.

Transmission design dictates the implementation method of the OD. In my Lincoln, it's the same as my MB, the OD is electrically controlled. In my previous Lincoln ('92 Mark VII), OD was mechanically selected via the shifter - but the wierd car lacked a shifter position for 2nd - only had 1, 3 & 4 as valid shifter positions.

I think in the case of the 722.5 transmission, it's basically a 722.X 4-spd tranny with an electrically-controlled OD gearset added post-design.

Who knows - just so long as it works - with a 3.69 rear gear, I need OD bad....

Hatterasguy · #9 12-26-2006, 02:57 PM

See they changed that on the later cars. If you had a 722.6 it would shift right to 5th. But they kick down so quickly lugging is not an issue.

wbrian63 · #10 12-26-2006, 03:33 PM

Yeah, and if I had a 722.6 transmission, I'd be stuck with that liquid-gold fluid available only from MB and by special dispensation from the Pope.

I think I'll take my old, dated 722.5.

I can also check the transmission fluid level on the tranny without some special Scotty-From-Star-Trek gizmo.....

Ain't technology grand????

Hatterasguy · #11 12-26-2006, 03:54 PM

I like the 722.6 a lot actualy. You almost never have to change the fluid or check it. And it actualy down shifts without having to beat it, like the old 722.4.

To each his own I guess. Local dealer charges $200 for a fluid change, bring it in every 60k-80k miles, other then that forget about it.

lkchris · #12 12-26-2006, 05:53 PM

Quote:

Originally Posted by wbrian63

Yeah, and if I had a 722.6 transmission, I'd be stuck with that liquid-gold fluid available only from MB and by special dispensation from the Pope.

I think I'll take my old, dated 722.5.

I can also check the transmission fluid level on the tranny without some special Scotty-From-Star-Trek gizmo.....

Ain't technology grand????

It's always sooo boring to hear from guys that don't have the new stuff--and therefore have no clue--just how bad the new stuff is.

A Mercedes with a 5- or 7-speed is light years better than the old 4-speeds, especially those that start in 2nd--meaning they're effectively a 3-speed. The new transmissions really transform the car's performance.

A few bucks more for fluids is irrelevant in the big picture.

wbrian63 · #13 12-27-2006, 08:45 AM

It's always so nice to hear from folks who actually take the time to post replies labling other forum members as clueless.

That's the problem with the written word - it's hard to include the wink-wink-nudge-nudge portion of the comment.

I don't criticise those lucky enough to afford a new or newer MB - I'd love to have one of those new CDI models your wife drives, but I can't afford that.

Technology is indeed grand - I wish my car had 1st gear start, but it doesn't. However, in order for me to afford an MB, I've got to do my own wrenching. I love to work on cars, and that helps, but in this instance, I must work on this car to afford it. Like most things, these wonderful cars that we all love so much are a real treat for the driver when things are working right. I am a big fan of technology, a true techno-geek. However, technology comes with a very high price when things go wrong. I can't afford the $100/hr prices at the dealership (or slightly less at a MB-capable indie) to fix all the gizmos on my 140 when they fail, and they will.

I completely agree that the newer cars with their 5, 6 and 7 speed transmissions are a real wonder. I completely disagree that offering that opinion also required labeling me clueless.

Happy Holidays.

deanyel · #14 12-27-2006, 02:49 PM

Quote:

Originally Posted by lkchris

A Mercedes with a 5- or 7-speed is light years better than the old 4-speeds, especially those that start in 2nd--meaning they're effectively a 3-speed. The new transmissions really transform the car's performance.

A few bucks more for fluids is irrelevant in the big picture.

The new MB transmissions, 722.6+, many of them anyway, seem incredibly troubled and shortlived as evidenced by the many posts on this forum. There are multitudes of problems, not just one or two. And they are very expensive to service, repair and rebuild. They seem to have about half the life and twice the rebuild cost of the four speeds. The four speed transmissions are relatively easy to service and repair, and more importantly they work. They have all the performance I will ever need for the way I drive. It is unimaginable to me, utterly unimaginable, that I would perceive any practical performance gain from a 722.6+ transmission. And I have no interest in taking care of one or risking a costly rebuild. A few bucks more for fluids is hardly the only relevant issue. In my "big picture" it is these alleged performance gains that are irrelevant.

DslBnz · #15 12-27-2006, 05:38 PM

The older transmissions are a PITA for starting in 2nd gear only. The European cars had a toggle switch that let them engage 2nd gear starts or first gear starts.

These things can be set to shift wherever the heck you want them too, with just a couple of simple tools.

The electronic transmissions attempt to "learn" your driving habits. There is a 1 - 2 seconds minimum delay built in between shifts that I find EXTREMELY annoying. Also, why is it the torque convertor seems inefficient at multiplying torque?

E420 (5th, 4th, 3rd, 4th, 3rd, 4th, 5th)
560SL (4th, 4th, 4th, 4th, 4th, 4th, 4th)