722.6 Major Issues--Help - PeachParts Mercedes-Benz Forum

Ben Brown · #1 10-25-2004, 08:04 PM

OK, guys I need your help with the MB 722.650 transmission in my 98 Jaguar XJR. I know, I know....but I've learned more about these tranny's on this forum than anywhere else.

So, my planetary gears implode (or explode) at 85,000. I had an aftermarket warranty on the car and they tell the transmission shop to put in a used one. Wasn't too happy, but they found one with 41k miles so I relented. Only problem was that the transmission was one digit off (so, I guess that means that it was for a different car). It goes in and throws a "wrong gear ratio" code-well there's a surprise.

Out it comes and I sourced a rebuilt 722.650 trans from Phoenix Transmission in AZ. After waiting for parts for two weeks, they finish it and it arrives. Up it goes and it promptly throws the same code!

The trans shop is lost on this tranny. My local indy Jag shop doesn't do tranny's. And I don't know a good MB trans mechanic in the DC area who might be able to help. Car has been in the shop for 7 weeks total.

Anyway, out of desparation, I'm wondering if anyone has experienced a similar situation--maybe MB Doc has seen something similar.

I did read a post where the person said the fault codes have to be removed from the trans computer or it will continue to hold the limp-home mode but I'm not sure if that applies here.

If anyone has any ideas, I would love to hear them!!!!!!!! No idea how we are going to resolve this.

Thanks in advance!

Gilly · #2 10-25-2004, 08:13 PM

I'm not sure if Jag uses the same control unit as an MB or not, I was unaware Jag used this tranny. What specifically is the fault code and description?

Gilly

Ben Brown · #3 10-26-2004, 05:05 AM

Gilly, yes the XJR's (supercharged) from 98 on use the 722.650. I think the XJ8's use the ZF trans. In fact that is part of the problem because there are relatively few XJR's when compared to XJ8's so there aren't too many Jag people who are all that familiar with them. The Jag dealers are told to simply replace any bad 722 (not rebuild).

I need to verify but I think the tech said code 731-incorrect ratio. I'll verify today.

Ben Brown · #4 10-26-2004, 05:51 AM

Gilly, Code 730-Incorrect gear ratio. Thanks Ben Brown

Ben Brown · #5 10-26-2004, 10:07 AM

Gilly, it's the wrong transmission. I went over to the shop this am and took a look at the #'s. The transmission they sent was a 722.605 not a 722.650! That might explain the gear ratio issue!

Gilly · #6 10-26-2004, 05:20 PM

OK, so maybe it's an incompatibility problem between the tranny control unit and tranny itself. I can try finding info on the code, but unlikely I'll have any info on a weird code like that, plus the control unit may have different codes which are specific to Jag. I will look though, sorry I can't be of more help.

Gilly

Ben Brown · #7 10-28-2004, 05:40 AM

A couple of weeks ago, I picked up a used engine and transmission as a back-up. We put the used 722.650 in. Works fine. The computer was recognizing that the 722.605 was the wrong tranny!