5 speed trans. bracket mounting

[Sven]

I just installed the engine + 5 sp Getrag OD transmission in the car. The transmission support bracket holes align dead center with the wide opening of the bolt track welded to the underside. Carl Nelson's conversion description notes that the 5 speed bracket straddles this opening. It does not seem that this location would provide adequate support. For one, the bolts turn in the wider opening. What is typically done here?

Thanks,

 

[decoupe]

5 spd transmission mount

Hope this helps. Both sides have captured bolt in the track - probably from an '81 528i (SQUARE HEADED BOLT M8X18 PN # 23711130250)

Doug

http://i54.photobucket.com/albums/g120/decoupe/IMG_4667.jpg

 

[AndyM]

Put the cross-bracket at a slight angle side-to-side so the nut captures the rail on both sides. Mine has been this way for years. It is plenty strong once the nuts are snugged down.

 

[John Buchtenkirch]

That made me real nervous (imagine if the tranny drops :shock so I made adapters out of ¼” plate and some grade 8 bolts. The washers raise the tranny the same amount the ¼” plate drops it. The plates are taped, bolts screwed in, heads cut of the bolts and then I tig welded the tops of the bolts (now studs) so they can’t turn. I used fine thread bolts for maximum bite into the ¼” plate. Hope this helps. ~ John Buchtenkirch

 

[sfdon]

2 choices-
rotate the support so one t-bolt is fore and one is aft of the t-bolt openg...

OR-

slot the support.

Your choice, they both work.

What does NOT work is the later cast support- they always break!

 

[AndyM]

That made me real nervous (imagine if the tranny drops :shock so I made adapters out of ¼” plate and some grade 8 bolts. The washers raise the tranny the same amount the ¼” plate drops it. The plates are taped, bolts screwed in, heads cut of the bolts and then I tig welded the tops of the bolts (now studs) so they can’t turn. I used fine thread bolts for maximum bite into the ¼” plate. Hope this helps. ~ John Buchtenkirch
View attachment 3014

View attachment 3015

That's a nice solution!

 

[John Buchtenkirch]

2 choices-
rotate the support so one t-bolt is fore and one is aft of the t-bolt openg...

OR-

slot the support.

Your choice, they both work.

What does NOT work is the later cast support- they always break!

Don, does BMW still make a stamped steel twin mount cross member or has it been superseded with the cast aluminum one ? I would like to stick with the twin mounts so I can use the single mounting ear on the right side of the Getrag 265 for an exhaust hanger mount. If BMW still makes a steel cross member might you know the BMW part number ? THANKS as always. ~ John Buchtenkirch

P.S. If the steel twin mount cross member doesn’t exist how many miles before the aluminum one starts cracking ? Maybe I’ll just duplicate it in steel myself.

 

[Sven]

Thanks for the tips. I managed to install the bracket in the angled position. The right side mounting is all the way forward in the track. The left side is on the edge of where the slot narrows down. Probably good enough. I did need to file down the transmission case a bit at the bottom center because the angled bracket interfered. I also filed off the small pin next to the bushing stud that fits in the bracket hole (to keep the bushing from turning I assume). For the bracket slots to reach each track bolt, the bushing had to be rotated 180°.

John - I do like your suggestion of using the 1/4" spacer bar. It seems a bit tight on the forward side of the bracket to fit the forward mounting bolt/nut for the adaptor plate. I may mess around with this in the future.

Doug - I noticed in your photo that you created a second bracket to mount a second transmission rubber bushing? Have others added a second support? It does seem odd that the stock bracket supports the transmission so eccentrically on just one side.

 

[decoupe]

Transmission mount

If I recall correctly, the transmission case has a "fork" for a transmission mount on both sides and a welder friend hacked (it's not pretty) a second mount for me. Thought this was a better solution to a single urethane mount - very solid.

Doug

 

[John Buchtenkirch]

Here is a better shot of the twin transmission mount cross member I used. However if Don says the cast cross member is junk (sigh) I certainly do believe him. ~ John Buchtenkirch

 

[sfdon]

I have had several of the cast brackets shatter. The stock stamped steel [later] bracket seems to last forever. I wouldn't trust a cast unit if I slotted it at all and the steel one when slotted stays clear of the down pipes.

 

[John Buchtenkirch]

I have had several of the cast brackets shatter. The stock stamped steel [later] bracket seems to last forever. I wouldn't trust a cast unit if I slotted it at all and the steel one when slotted stays clear of the down pipes.

Don, does the steel cross member come as a twin rubber mounts or is it single mount ? If it’s a twin would you know a part number or what year & model car it was on ? Thank you again. ~ John Buchtenkirch

 

[sfdon]

here is the link - part nos and pic......

http://www.realoem.com/bmw/showparts.do?model=3995&mospid=47163&btnr=23_0399&hg=23&fg=10

Here is the link to the uber expensive angled mounts [2 required] for the cast support off the 1985 e28 and e24 with Getrag 265 2nd edition...

http://www.realoem.com/bmw/showparts.do?model=DC11&mospid=47220&btnr=23_0381&hg=23&fg=10

Note the the e23 used a different one from these!

Just a bit wider...


http://www.realoem.com/bmw/showparts.do?model=6874&mospid=47192&btnr=23_0385&hg=23&fg=10

Here is the USA version for the the Getrag 265 in stamped steel for the 535i.

http://www.realoem.com/bmw/showparts.do?model=DC74&mospid=47231&btnr=23_0052&hg=23&fg=10

And note that this link shows the wrong pic for part #23711175731 !!!


Tons of fun......

 

[sfdon]

BTW- keep in mind that I have run my car up to 22lbs of boost - I break a lot of everything.
If you ad up the diffs, trannies and engines, the number would be 12.
Still- the cast supports have a bad reputation.

Don

 

[DaveG]

Here is the order i made to Penske a couple weeks ago for the cross member...

1/23711175314 |CROSS MEMBER (09/80 to 09/82) (Manual Tr| $37.03| $37.03
1/24711127288 |RUBBER MOUNTING (09/80 to 09/82) (Manual| $21.44| $21.44
2/23711130250 |SQUARE HEADED BOLT - M8X18 (09/80 to 09/| $5.26| $10.52

I bought a couple extra square headed bolts as mine were pretty sad....
I only made 1ea. T-bar similar to the one shown earlier.
Mine is 5/32 thk x 3/4 wide 4.5 in long with outer holes on 3.5 in centers. The center bolt is just a std 8 mm bolt with a small tack to keep it from rotating. It's head fit right on the wide spot in the track, so no need for fancy tapped holes.... The opposite side was OK so no t-bar there. . It all fit perfectly centered on the trans ....No odd angles were required.
DaveG