please help!!! 740 i trans

chris hinson · 05-15-2003, 07:32 AM

my trans sometimes will not revers unless i give it some gas, then it pops into gear, almost like its low on fluid, but it goes forward just fine. This morning I took it to the dealer to have the trans serviced and the guy talked me into havind a diagnostic test done instead of a service, $73. He says that its not coming back with any problems so the trans will need to be replaced $6000.
I asked if it was fixable and he said they don't do any internal work there, but i could take it to a trans shop and they could help. My brother is a Mechanic and he thinks it could just be the seals on the vavle body, or it just sticking. I thought they were going to look at these type of things. Hell the onboard computer could have told me the same thing this $72 service did. I dont want to take it to some shade tree mechanic shop that'll keep it for three months just to tell me it needs a new one. What can i do to hav these things checked out or do it myself. thank you. ant info is appreciated!

autobonrun · autobonrun's Garage

I rebuilt the unit on my 93 740 in November that exhibited the same problems. If you send me a private message with your email, I'll send you a writeup on the repair procedure that includes pictures. It's in Acrobat Reader format.

Basically, you can get a replacement valve body for about $600 with your old unit turned in as a core or you can have someone rebuid your unit for about $450, or you can rebuild it yourself for about $150. I chose to rebuild mine myself and the entire replacement is about a two day job.

The most expensive component is the fluid. It takes about 13 liters (3 five liter containers). Each 5 liter container is about $140 from the dealer, so add another $420 for the fluid. You could save and reuse the old fluid if it's been changed recently but if it has never been changed, I'd add new fluid.

chris hinson · 05-15-2003, 02:09 PM

yes that would be appreciated. I'm a little confused about the fluid. the dealer was going to charge me $150 to change the fluid and filter, but everyone is saying that this fluid costs $100 plus per container, and Autozone says I can use any Dextron III fluid????

autobonrun · autobonrun's Garage

Quote:

Originally posted by chris hinson
yes that would be appreciated. I'm a little confused about the fluid. the dealer was going to charge me $150 to change the fluid and filter, but everyone is saying that this fluid costs $100 plus per container, and Autozone says I can use any Dextron III fluid????

First, I'd say that Autozone is very incorrect. Check out these links.

http://www.peterschmid.com/zfoilguide.htm

http://www.peterschmid.com

http://home.socal.rr.com/tyrone/SD92-114.pdf

Not any transmission fluid should be used in these cars.

Next, I would ask the dealer how much fluid they planned to change for $150. Even if you just drop the pan and filter, you're probably looking at 8 liters. This would take 2 five liter containers or around $280 excluding labor. The 13 liter figure I gave earlier is when you drop the entire valve body and drain the torque converter. The recommendation to use LA 2634 fluid is from ZF not BMW. ZF makes the transmission.

I received your email and will send you the repair procedure I have. It is still a work in progress but is about 95% complete and has been proof read and commented on by a reputable transmission repair specialist. I'm adding one more photo in the near future but it will give you an idea of what is involved in its present form.

chris hinson · 05-16-2003, 06:41 PM

thank you very much!

chris hinson · 05-16-2003, 07:02 PM

oh yeah, if i decide to do it myself or get a replacement, where can i find the parts?

autobonrun · autobonrun's Garage

I'm not sure if Pelican supplies a complete rebuild kit or not. If they don't, I'll drop you a PM with other options.

Bottom line, if you have the time, you can do the entire job yourself in 2-3 days for less than $700. This assumes you may have to buy some tools like #27 torx head fittings, fluid transfer pump, etc. My writeup lists every tool you will need. Unfortunately, I can't get this 1.3 meg file through your email.

chris hinson · 05-20-2003, 04:54 PM

damn, i wonder why you can't get it through! that would realy help. is there an easy way you can break it up? its the size! here is another address. marilynhinson3282@msn.com, please try again. just in case my rofile is wrong mine is chrishinson@msn.com. do you know of any links that i might visit to get the info? i have rebuilt a trans bfore so i would like to do it myself and save some money!

autobonrun · autobonrun's Garage

I've been out of town for the past week but I just tried sending again to the 2 addresses you posted. If this doesn't work, I'll see if Pelican will be interested in posting the article after I make a few minor changes to it. My references to 8 liters of fluid should be 13 liters for a complete valve body drop and drain of the torque converter.

I also want to add a photo showing some of the parts that need to be replaced as during the rebuild. It always helps to know what you will be working with in advance. Anyway, I hope this try gets through.

autobonrun · autobonrun's Garage

It looks like the file may have made it to the first email address you listed, but I got another failure notice to yours. I'm not sure what's going on with that. Let me know if you are able to open the file.