I've posted on this topic before with no results. My 1990 300E 2.6L has no reverse. Im going to try a used transmission, but I dont know which ones are all interchangeable with mine. I found one locally for a 1987 260E, the seller says it will fit, but Id like to make sure. Any advice would be appreciated. Thanks.

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"Picture Me Rollin' In My AMG Benz"


Past Cars:
2001 E430 4Matic
1990 300E 2.6
1973 450 SEL
1977 300D

Before you replace your transmission do a search on this site. There is a switch on these transmissions that if fails will render reverse inop. Worth a shot.

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Brandon



2008 S550
1957 Dodge D100
1967 VW Microbus 21 Window
2001 Suburban
2004 Beach cruiser bicycle
-----------------GO DUKE!-----------------

"It cannot be emphasized too strongly or too often that this great nation was founded not by religionists, but by Christians; not on religion, but on the Gospel of Jesus Christ. For that reason alone, people of other faiths have been afforded freedom of worship here." Patrick Henry 1776

If it were mine, I don't think I'd go for a used tranny without first doing some homework. I would go to a good Indy tranny shop, one that's experienced with Mercedes, and have yours evaluated. You'll hope the problem is a switch, as suggested in the previous response, but if it isn't you can find out what it will take to repair what you have. You know your transmission but you don't know the history of the "used" one you're considering. In the alternative, you may want to consider a "rebuilt" as one of your options.

As for information on Trannys that will fit your car, I'd call the "Sun Valley Mercedes Dismantlers" who make a business of rebuilding Mercedes trannys and they claim to know every Mercedes tranny in the book. Their telephone number is 1-818-768-0704. In the alternative, they respond to emails and their address is SVMBZ@aol.com. I have found them to be very knowledgeable and helpful.

I hope this helps,
William

According to the ATSG manual on the 722.3/4 transmissions "no postive contract in reserve gear" is either"

1. check lining plates and lip sealing rings on piston of LB3 and renew if required, or

2. renew one-way roller clutch in gear assembly.

It's most likely #1 - you blew a seal in the reverse piston. If so, there's nothing really wrong with your transmission. You could have another 100k in the forward operation. Replacing seals in the reverse piston is not that big a job - no need to even get into the inner workings of the transmission. The problem is of course you have to R and R the transmission which is six to seven hours. "Most people" recommend rebuilding the transmission once you've taken it out on a 14 year old car. But "most people" like your money. It isn't absolutely necessary if the transmission is otherwise operating properly. Sorta depends on what your future is with the car. But I agree, if transmission is OK better to rebuild yours than get a rebuilt in which you don't know the history.

Well, the forward gears work excellent, and reverse works until it heats up. The only reason I was looking into a used tranny is because I live in Halifax, Nova Scotia, Canada, and there arent many tranny shops that like Benzes. Im also getting an awesome deal on the used tranny cause I know the guy, but I just wanna know if it will fit. But when the old tranny comes out, I will have an estimate on just fixing the reverse, and then weigh out my options. Thanks for your help.

__________________
"Picture Me Rollin' In My AMG Benz"


Past Cars:
2001 E430 4Matic
1990 300E 2.6
1973 450 SEL
1977 300D

I recently went through this with my 1991 420SEL, which has the 722.3 transmission. Over the previous year or so, the time to engage reverse had grown longer, until it was taking 4 seconds or more. Then, it started to not engage in reverse at all, until you blipped the gas a bunch of times (problem was worse when the transmission was warmed up or hot). Miles on the car was right around 170,000.

As stated elsewhere, the problem is with the B3 reverse clutch. Most of the time, it is that the reverse clutch plates are worn out. Unfortunately, this requires removal of the tranny, and opening it up. This of course leads to the pros and cons of whether to do a total rebuild, versus just replacing/repairing the B3 clutch plates. (Or, alternatively, dropping a rebuilt tranny in.)

My transmission shop told me that the rest of the transmission looked to be in pretty good shape, so he was comfortable with either approach. The cost difference was $1300 for just repairing the B3 clutch (as well as replacing seals, etc., while the tranny was out), versus $2600 for a total rebuild. Keep in mind that this is in the inflated-price confines of the SF bay area - I think both prices would be a fair amount lower in other locales. It was also only a 3 month warranty on just the B3 repair, versus 1 year for the total rebuild. But, I went with just the B3 repair, since 1) I'm not going to keep the car for more than a year, and 2) the B3 problem is a known weak point of this transmission, and 3) the transmission shop advised that wear on other parts of the transmission seemed pretty low. (If I knew that I wanted to keep the car for multiple years, I probably would have gone for the rebuild.)

It has been about a month and 1500 miles or so since the repair, and the tranny is working perfectly since, including rapid engagement of reverse.

The one thing that frustrated me a little is that earlier versions of the 722 transmission (722.0 - 722.2) have a B3 band, instead of a B3 clutch, which can be adjusted externally, without removing the transmission. On one of these older transmissions, the fix for lack of reverse gear engagement can be as easy as a 30 minute adjustment.

Good luck,

Bob Schleicher
1991 420SEL, 172,000 miles