Jump to content

Recommended Posts

I bought a Getrag 245 from a fellow who said he and his friends had bought it for their race car, and used it only once or twice before figuring out they’d never get into 5th gear with it.  In other words, worked when they sold it to me.  It came with a shortened driveshaft complete with new giubo, a slave and lengthened flexible brake line.  I opted for the Blunt shift kit, Sachs clutch and the 323i throwout bearing.  It being an unknown box we went through it pretty thoroughly and put it back together.  Looks nice inside, all synchros measure out almost like enw and all rods straight, gears nice.  

 

But the devil’s in the details, and now that I’m installing it I have gotten into a little bit of a funhoue.  First I could not get the whole thing shoved into place.  Some chiseling of a burr on the clutch kit and chamfering the end of the input shaft splines and that was solved.  Then, to test fit the driveshaft (again, this is all second hand stuff I have never installed) I hoisted it onto the output shaft, bolted up the center support loosely and hand-bolted the guibo to the driveshaft.  A pretty fine fit, maybe a little more gap between driveshaft flange and trans output flange than I expected (l/8” maybe), but the diff is installed all the way back and I was thinking it’s a gap I can easily close.  

 

Then I realized that I couldn’t turn the driveshaft because the giubo was making contact with the shift selector rod.  I measured the giubo diameter — it was 107mm at the widest point, a mm larger than it should be.  I ordered a fresh one from Blunt.  I also noted that the threaded tips of the 50mm bolts that connect the giubo to the trans output flange were rubbing against the heads of the bolts that protrude from the output flange seal cover.  

 

Just to see what effect it would have, I reinstalled the bolts with washers under the heads, which gave me just enough room that the giubo-to-flange bolts didn’t click on the output shaft cover bolt heads.  At the same time, I smoothed off the outer edges of my existing giubo with a sander to bring the outer diameter to 106mm at the widest points.  When I reinstalled it with the washers it continued to rub against the shift selector rod, but less, and I discovered that the bit rubbing was the front of the guibo, against the collar where the shift selector exits the trans case.  

 

In a moment of clarity, I measured my old 4-speed to see what the distance is between the front of the trans output shaft flange and the trans output shaft cover bolts (the ones that on the 245 had been nicking the 50mm bolts initially).  It was 18mm, give or take a hair.  Back to the 245 and measure... lo!  Maybe 12 mm?  Six millimeters is a lot of real estate in this neighborhood, as many of you know.  

 

I am not sure the best question with which to open the bidding.  I don’t imagine we could have installed the flange too deep when putting the trans back together. I think it’s a positive stop.  But we need to buy back at least a couple of mm.  How (there’s a good starting question!)?  Are there shims for this that we could put on before the flange?  Are there 3 bolt flanges of different depths?  I can’t wait to solve this problem only to find that the driveshaft is too long!

Link to post
Share on other sites
  • Replies 49
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

File this away in For What It's Worth:  all guibos are not the same.  I found that the Febi/Bilkstein fits without interference with the selector rod and the Meyle hits it.  1 other thing I learned du

That's what's great about light twin aircraft, you loose one engine and the other one will take you all the way to the crash site. Sorry a old aviation joke.

I've attached pics and measurements of the 320i trans / Guibo flanges. The two taller ones, one a 4 hole, the other a 3 hole are from 245 / 5 transmissions rescued from salvage yards 20 years ago. I d

Posted Images

11 minutes ago, 0257 said:

I bought a Getrag 245 from a fellow who said he and his friends had bought it for their race car, and used it only once or twice before figuring out they’d never get into 5th gear with it.  In other words, worked when they sold it to me.  It came with a shortened driveshaft complete with new giubo, a slave and lengthened flexible brake line.  I opted for the Blunt shift kit, Sachs clutch and the 323i throwout bearing.  It being an unknown box we went through it pretty thoroughly and put it back together.  Looks nice inside, all synchros measure out almost like enw and all rods straight, gears nice.  

 

But the devil’s in the details, and now that I’m installing it I have gotten into a little bit of a funhoue.  First I could not get the whole thing shoved into place.  Some chiseling of a burr on the clutch kit and chamfering the end of the input shaft splines and that was solved.  Then, to test fit the driveshaft (again, this is all second hand stuff I have never installed) I hoisted it onto the output shaft, bolted up the center support loosely and hand-bolted the guibo to the driveshaft.  A pretty fine fit, maybe a little more gap between driveshaft flange and trans output flange than I expected (l/8” maybe), but the diff is installed all the way back and I was thinking it’s a gap I can easily close.  

 

Then I realized that I couldn’t turn the driveshaft because the giubo was making contact with the shift selector rod.  I measured the giubo diameter — it was 107mm at the widest point, a mm larger than it should be.  I ordered a fresh one from Blunt.  I also noted that the threaded tips of the 50mm bolts that connect the giubo to the trans output flange were rubbing against the heads of the bolts that protrude from the output flange seal cover.  

 

Just to see what effect it would have, I reinstalled the bolts with washers under the heads, which gave me just enough room that the giubo-to-flange bolts didn’t click on the output shaft cover bolt heads.  At the same time, I smoothed off the outer edges of my existing giubo with a sander to bring the outer diameter to 106mm at the widest points.  When I reinstalled it with the washers it continued to rub against the shift selector rod, but less, and I discovered that the bit rubbing was the front of the guibo, against the collar where the shift selector exits the trans case.  

 

In a moment of clarity, I measured my old 4-speed to see what the distance is between the front of the trans output shaft flange and the trans output shaft cover bolts (the ones that on the 245 had been nicking the 50mm bolts initially).  It was 18mm, give or take a hair.  Back to the 245 and measure... lo!  Maybe 12 mm?  Six millimeters is a lot of real estate in this neighborhood, as many of you know.  

 

I am not sure the best question with which to open the bidding.  I don’t imagine we could have installed the flange too deep when putting the trans back together. I think it’s a positive stop.  But we need to buy back at least a couple of mm.  How (there’s a good starting question!)?  Are there shims for this that we could put on before the flange?  Are there 3 bolt flanges of different depths?  I can’t wait to solve this problem only to find that the driveshaft is too long!

 

Link to post
Share on other sites
Just now, 0257 said:

 

Just got the output shaft flange off.  Here it is, all of 15mm deep, a lot shallower than my 4 bolt.7850A640-C3E4-4B66-BE0D-4EB19EDEB178.jpeg

Link to post
Share on other sites
1 hour ago, 0257 said:

In a moment of clarity

For you perhaps but I need pictures😉

Nothing to be gained by comparing output flanges from different models of trannies, since they are completely different assemblies. No reason for the output flanges to have the same dimensions.

i would like to see a pic of the bolts you are using... 

Link to post
Share on other sites
Posted (edited)

I wonder if they left the speedo drive gear off the shaft, the only reason I say that is if I recall corectly, it about 6mm wide, how many threads were showing on the shaft when it was togeather? There should be only 2 or 3 if I recall.

 

 

PS this is just a wild ass guess!

Edited by Son of Marty
Link to post
Share on other sites
5 minutes ago, Son of Marty said:

I wonder if they left the speedo drive gear off the shaft, the only reason I say that is if I recall corectly, it about 6mm wide, how many threads were showing on the shaft when it was togeather? There should be only 2 or 3 if I recall.

 

 

PS this is just a wild ass guess!

Good one, but the speedo drive gear is in, and as the attached photo reflects the nut just barely clears the threads...CE56F719-865A-4271-9483-125EF50FC4B7.jpeg

Link to post
Share on other sites
17 minutes ago, tech71 said:

For you perhaps but I need pictures😉

Nothing to be gained by comparing output flanges from different models of trannies, since they are completely different assemblies. No reason for the output flanges to have the same dimensions.

i would like to see a pic of the bolts you are using... 

50mm factory bolts. Again, the issue appears to be the distance between the front of the trans output flange (where it meets the driveshaft) and the back of the transmission.  Not enough distance with this flange to fit the factory 50mm bolts and nuts, and even if I space those with a washer I get front outside edge of giubo rubbing against shift selector surround where it meets transmission case.  Seems I need a flange with a longer collar. Or, uh, something.  Keep the ideas coming! 

E25264C3-06A5-4FB1-98DE-AD431D8EAC7C.jpeg

Link to post
Share on other sites
Posted (edited)
34 minutes ago, 0257 said:

Keep the ideas coming! 

OK, you mention some difficulties getting the trans stabbed in.

Are you absolutely certain that it is fully and evenly seated? 

Did you change the pilot bearing? a pilot bearing not seated deeply enough might compress the entire mainshaft assembly and force it aft a little..... Hey, its an idea!

Is that really a pair of vise grips marring up the weakest and most highly stressed area of your output flange?🤔

Edited by tech71
Link to post
Share on other sites
1 minute ago, tech71 said:

OK, you mention some difficulties getting the trans stabbed in.

Are you absolutely certain that it is fully and evenly seated? 

After the “plastic surgery” on the clutch and the input shaft spline front edges the trans mated to the block just like it should.  It’s snug now.  Not sure that should affect the output shaft flange distance from back of trans case, as all those parts travel together.

Link to post
Share on other sites
30 minutes ago, jimk said:

Are 50 mm bolts, the bolt length for the 4 bolt flange or the 3 bolt flange.  The 8 bolt guibo is thicker than the 6 bolt guibo.

50 mm bolts are for the 3 bolt flange. 61 mm bolts are for the 4 bolt flange.  

Link to post
Share on other sites
1 minute ago, ray_ said:

That flange looks odd to me...

Well, you should hear what people are saying about you.

 

How?

  • Haha 1
Link to post
Share on other sites
9 minutes ago, 0257 said:

Well, you should hear what people are saying about you.

 

How?

In an odd way.

 

😁

 

I'll have a comparison in a few days. Maybe.

Link to post
Share on other sites

I had a similar problem with a 3 bolt flange on a 245 /5 where it sat too deep and bolts were making contact with the trans housing or something. I replaced the 3 bolt flange with another similar one. I think there may be different sizes as far as dept. I have one laying around in my garage from a 245 / 5. I’ll measure it’s collar.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...