190E won't move in 1st or Reverse - PeachParts Mercedes-Benz Forum

DieselPaul · #1 05-20-2016, 01:00 PM

Have a 722.4 that is second gear starting (I think it's supposed to?). If you put it into reverse you feel it go into a gear but if you push on the throttle it just revs up against the torque converter stall like you're brake boosting it.

In a straight line around the parking lot it shifts fine between 2 and 3, I don't have enough room to get up into 4th.

If you select L to get the car into 1st it behaves the same as it does in Reverse. Acts like the parking brake is set. In neutral the car rolls freely and smoothly.

I also noticed if you rev it up in Neutral it will creep forward a little bit.

The fluid is nice and clean, doesn't smell bad and is a good color. Car has fairly low miles on it.

Is this indicative of anything other than a bum trans? I would rather fix this trans than replace if it all possible, but I have never experienced this type of failure.

The car has sat for about 10 years, some have suggested since 2-3-4 seem to work, get it out on the road at highway speed and just run it for a while and see if something unsticks.

What say you PeachParts?

97 SL320 · #2 05-20-2016, 01:50 PM

I'd lean towards a valve body issue.

Do you have a clutch apply chart?

I've seen some trans ( Ford 4 SP in a Ranger ) that have welded a clutch pack solid and cause what you describe except they pull in neutral and are tugging against the parking pawl in park and lack reverse while dragging the engine down like ti is in gear..

97 SL320 · #3 05-20-2016, 09:05 PM

Found an apply chart for a .3 , should be the same as a .4 .

And some info here
GEARS Magazine - December 1999

Any idea why was the car parked?

Stretch · #4 05-20-2016, 10:39 PM

Have you checked the obvious => shifter bushings (as well as the fluid)?

Next step would be to measure the working pressure

Could be the freewheel clutch which is meant to operate for first and reverse

97 SL320 · #5 05-21-2016, 09:23 AM

The free wheel clutch / sprag is applied in 1 and R , slipping will cause no motion.

One of the friction elements is remaining applied, this is why the motor is against the torque converter / car won't move. Drag race cars apply 2 elements so the motor can be brought against the converter then one is released launching the car.

As a quick guess I'd say that B1 is remaining applied but that might not be true since 3 rd supposedly works. I'd want the car wheels to be elevated and see if 4 th can be engaged.

Stretch · #6 05-22-2016, 06:12 AM

Quote:

Originally Posted by 97 SL320

The free wheel clutch / sprag is applied in 1 and R , slipping will cause no motion.

...

That's how I read the problem => thread title

97 SL320 · #7 05-22-2016, 07:23 AM

A slipping sprag will give no motion but the engine will rev freely.

Our guy can't move but the engine is against the torque converter like the parking brake is on. ( sprag is holding along with another element, this locks the gear train. )

DieselPaul · #8 05-25-2016, 11:45 AM

Car was initially parked due to the owner going to jail. Car traded hands a few times after it sat for several years through people that didn't know Benzes. Now I have it.

I did drain the pan, fluid looked fine, refilled with like 4-5 quarts of fresh ATF and got the level right. I took the car on about an hour drive (highway and around town, speeds up to about 85mph) and it ran and shifted great through 2-3-4 but once I got back, 1st and Reverse do the same thing. You can actually get the car to stall in Reverse which is odd.

I jacked the car up and the wheels turn freely and the car can be rolled in neutral easily (heard of some bizarre parking brake failures)

I have a line on a transmission with similar miles for $100 at a friends shop a few miles from my house. I may just opt to replace the trans. Dropping the existing trans and tearing into it on an IF may not be as time effective as dropping the trans and replacing it with a known good unit.

I appreciate everyones input so far.

The shifter bushings are pretty toast but all the gears seem to engage well enough.

Trying to get the car into reverse or first with the rear wheels off of the ground is interesting and something I have not tried. I'll try that and report back.

97 SL320 · #9 05-25-2016, 09:06 PM

Reverse stall in a trans without a lockup converter is very odd, unless the motor is having an issue like a vacuum hose opening up due to the motor moving.

A broken accumulator piston might cause this. On domestic trans I've seen check balls wear through the separator plate and cause all sorts of odd behavior especially if the check is a 3 way not the normal 1 way.

Found this: ( more at the web site ) , while the unit in question had no fwd and good reverse, I wonder of your valve body has something jammed in it giving you a drag race trans brake.

TRNi | Transmission Rebuilders Network International, Transmission Rebuilder, Transmission Repair

Subject: MERCEDES_722_3, No forward, solid reverse
Date: Fri Aug 2 11:48:01 PDT 2002
Subject: MERCEDES_722_3, No forward, solid reverse

Hi All, The VIN says this is an 81. Yes it is a 6 bolt pan 722.304. We pulled the servo cover and as several of you have suggested, the servo was broken. My dealer said $122.50; pricey little bugger. Once we get it back together and working then I will post the fix. Thanks to all that replied and especially to Don Stone and Tranibob for the help. Thanks again, Jerry

Jerry Martire - Shirlington Transmissions
transmission_doctor@worldnet.att.net
TRNi Member Since: 9/5/00 (7 | 153)
MORE RESPONSES:

FIX:

Date: Wed Aug 7 05:11:05 PDT 2002
Subject: MERCEDES_722_3, No forward, solid reverse

It's fixed! We installed the new B2 servo but still no go. I decided to drill the B2 servo cover for a pressure guage to verify wether we had a hydraulic problem or a mechanical problem. This test showed no pressure on the B2 servo, so I knew for certain it was a hydraulic problem, so we pulled the valve body again and went through it with a fine tooth comb. Found that the B2 shift valve was jammed by a piece from the broken servo. Put it all back together and everything worked great. Thanks for all the help. Jerry

Jerry Martire - Shirlington Transmissions
transmission_doctor@worldnet.att.net
TRNi Member Since: 9/5/00 (7 | 153)

Stretch · #10 05-26-2016, 01:33 AM

There's a gizmo on the transmission that helps these petrol engines "sense" if the transmission is in gear or not. Not so surprising that it is stalling in reverse.

It still isn't clear to me if the car actually moves in first gear and reverse or not - can you confirm?

97 SL320 · #11 05-26-2016, 05:06 PM

From his post

Quote:

If you put it into reverse you feel it go into a gear but if you push on the throttle it just revs up against the torque converter stall like you're brake boosting it.

In a straight line around the parking lot it shifts fine between 2 and 3, I don't have enough room to get up into 4th.

If you select L to get the car into 1st it behaves the same as it does in Reverse. Acts like the parking brake is set. In neutral the car rolls freely and smoothly.

Stretch · #12 05-28-2016, 01:28 AM

Yeah but does it move?

Anyway it seems like Paul is planning to replace and not bother with this any more as he's got a WTB ad running

97 SL320 · #13 05-28-2016, 08:24 AM

Apparently not

Quote:

If you select L to get the car into 1st it behaves the same as it does in Reverse. Acts like the parking brake is set. In neutral the car rolls freely and smoothly.

DieselPaul · #14 12-28-2016, 11:29 AM

Sorry I never followed up with this thread, picked up a used trans locally for $50 and put that in, car is running and driving great. Seemed like the amount of effort to dismantle the trans in the chassis, or pull it and mess with it was much greater than $50 and swapping transmissions.

The car absolutely would not move in first or reverse. If you leaned on the throttle really hard it would stall the car in reverse. It was very bizarre. I moved shops during the trans swap so the old transmission was scrapped when the shop got cleared out so I was not able to do a postmortem on the old transmission. I really wanted to know what was causing that.