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Tranny in the tunnel  Rate Topic 
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 Posted: 07-22-2005 03:10 pm
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Ron Earp
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Is my tranny crooked? It looks that way, but I cannot figure out why.  The engine looks straight, is this normal? I know the tunnels are a little offset as well as the diff pinon flange, but this is the first time I've tried the five speed in the car.  Any comments or observations?


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 Posted: 07-22-2005 04:48 pm
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Mark Rosenbaum
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In the photo, the transmission does look offset to the right a little bit, and the engine/tranny assembly appears twisted slightly counter-clockwise, too.  I'd suspect that this is due to a buildup of tolerances in the chassis parts, the transmission-to-transmission-mount adapter, and in the way the engine mounts were installed.

Normally, when the engine mounts are still a bit loose, the transmission crossmember should slip onto its mounting studs without interference.  The engine/tranny assembly is then pried and jacked into alignment, and finally all three mounts are tightened.  Properly done, this minimizes the static stress on the engine mounts, making their failure far less likely.

SAFETY WARNING:  The transmission crossmember mounting studs tend to be a bit soft in some cars, and as a result the pinch-type lock nuts used by the factory may damage them after being removed and replaced a few times.  Consequently, it is vital to examine each stud very carefully, and to replace it with a Grade 5 or better bolt if there is any doubt as to its condition.  For a race car, you may wish to use Assembly grade drilled bolts and cotter pins.

If you find that the driveshaft hits the stiffener at the rear of the transmission tunnel (which isn't likely except in 4-speed cars), be aware that the factory used several different stiffeners having a variety of shapes.  AFAIK, all of these had the same Jensen part number, and none is documented by anything other than a line drawing in the parts book.  I'd think you could fabricate a stiffener that would offer proper clearance to both driveshaft and road without arousing the ire of any scrutineer.

 

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 Posted: 07-22-2005 05:45 pm
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Ron Earp
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Hey Mark,

This is in reference to the same question I ask a week or so ago - my chassis bolts come nowhere near close to that mount and bushing for the tranmission. The mount and bushing for the transmission is a good 9 inches beyond the factory bolts for the transmission - no way to make them line up. 

Were there big changes like this through the years? Or, did the four speed have a completely different mounting position than the 5 speed?

Ron

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 Posted: 07-22-2005 06:14 pm
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Brett Gibson JH5 20497
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Hey Ron, I have'nt been under my car for a couple month's but if I remember right the 5 speed tranny is off to the passenger side a bit, I've read thru your note but I'm still a little foggy on what you mean by   ( my chassis bolts come nowhere near close to that mount and bushing for the tranmission ). but anyhow I need to spend a little quality time this weekend under my baby, ( the car that is ) so if I can take some pict's for you or other measurements let me know ASAP cuase I wont be back at this computer till Monday 7/18.

Brett

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 Posted: 07-22-2005 06:35 pm
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Ron Earp
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The chassis has bolts sticking down that are supposed to go through the transmission mount to support the tranny. But, my bolts are about 9" toward the front of the car in relation to the tranny mount. Look at the top picture, see those studs on each side of the tranny coming from the bottom of the car? You can't tell in the picture, but there is no way those studs are anywhere close to the bushing on the bottom of the tranny - they are about 9" toward the front away from the bushing, so, no brace can bolt to them and bolt to the bushing.

Hold on, Which of these are mount sfor 5 speed gear boxes?





I think it is the top one in the second picture but that thing is WAYYYYYYY too deep - that is, if yo uheld it up to the car where it should go it hangs down 4-5 inches.  Think I will have to make my own mount.

Ron

Last edited on 07-22-2005 06:36 pm by Ron Earp

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 Posted: 07-22-2005 06:55 pm
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Mitch Ware
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You use both of the brackets in the bottom photo. In this picture you can see the bottom one goes across the tunnel right where it begins to go straight back, and you can see the studs that the top one goes on to the left (front of the car). Perhaps you are missing the studs for the front one?

Mitch Ware
1974 JH-5 #111119670
1971 TR-6 #CC66950LO

Attachment: Bottom Done 001x.jpg (Downloaded 30 times)

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 Posted: 07-22-2005 06:58 pm
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Brett Gibson JH5 20497
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Ron, your correct the second pict top mount is for the 5 speed, I'll measure off the distance to the studs on my car from a couple of refrence points and let you know, as for hanging down I had'nt thought that an issue but there again I'll take some measurements, you know if you did'nt live so dam far away I'd just drive over and let you go to town, but thank god for the internet , eh what .................

Brett.

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 Posted: 07-22-2005 07:14 pm
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Ron Earp
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That second bracket, did it support the two piece driveshaft bushing holder or something? I don't have that since I am using a single piece. Wait......Brian has a JH in Apex, 3 miles from me.  Anyone have his contact info? I used to but my IBM has been "rebuilt" and I lost all my address book entries. Thanks,

 

Ron

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 Posted: 07-22-2005 07:19 pm
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Mitch Ware
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I don't know if the 2nd bracket did anything or not. My car didn't have a driveshaft when I bought it, and I put a new 1 piece driveshaft from Delta on it when I put it back together. I simply assumed the 2nd bracket was for stifness

Mitch Ware
1974 JH-5 #111119670
1971 TR-6 #CC66950LO

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 Posted: 07-22-2005 07:21 pm
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Mark Rosenbaum
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It's my understanding that the mounting studs for the transmission crossmember are located in the same place for both 4- and 5-speed cars, but I'm not an expert on 5-speed cars and may be wrong.  That said, my understanding is provided below.

The 5-speed attaches to the car through (a) an adapter bracket, (b) the same transmission mount ('insulator') used by the 4-speed, and (c) the same transmission crossmember used by the 4-speed, as shown in the 'Cases and Bearings - Exploded' line drawing for the 5-speed transmission.

Attached are photos of 4- and 5-speeds with bell housings, unfortunately not to quite the same scale.  Nonetheless, it's quite clear from the photos that the 5-speed has a longer case and a much shorter bell housing than the 4-speed.

Based on these photos, with respect to the front face of the bell housing, I'd expect that the rear mounting surface on a 5-speed is actually two or three inches forward of the mounting foot on a 4-speed.  If that's actually the case, then it would make sense for the adapter bracket to make up the difference and place the transmission crossmember in the same location for both 4- and 5-speed cars.  From the line drawing of the bracket, it appears that this is precisely what it's intended to do.

IIRC, you mentioned elsewhere that you bought this 5-speed as part of a parts collection intended for a 4- to 5-speed conversion.  Since you've already had a problem with the drive shaft, perhaps you should be suspicious of the remaining parts.  You might measure the front-to-rear dimensions of the bell housing, transmission, etc., and compare these to those from parts known to be factory items.

If all else fails, it should be a simple matter to drill a pair of holes on either side of the transmission tunnel so that things will line up and mount to the car.

One last thought here, you might also check the engine mount brackets that bolt to the block.  It's conceivable that they might be the wrong parts, or installed incorrectly, or perhaps both.

Attachment: trannsmission comparison.jpg (Downloaded 108 times)

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 Posted: 07-22-2005 07:35 pm
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Mitch Ware
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I would tend to think that if your shifter is coming out of the hole in the tunnel in what appears to be correctly centered, and the mount that goes on the back of the shifter and comes out the hole behind the shifter allowing you to put a washer and nut on it, then the engine/tranny are in the right spot.

Mitch Ware
1974 JH-5 #111119670
1971 TR-6 #CC66950LO

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 Posted: 07-22-2005 07:45 pm
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Ron Earp
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It is an odd puzzle.  The engine is right, there is little room and the engine is where it is - in the right place. The bellhousing and transmission are correct and bolt up nicely, there really isn't any other way is there? Your transmission pictures look to be exactly like my own.

I don't know why this thing had bolts through the body in the wrong place, but it does, and they look very "factory" for lack of better work. You correct though, it is a simple matter to drill four more holes and make a bracket to get this thing right.

As for the shifter, well, mine is not "centered" in the hole but is back about 1.5" I'd guess. Still shifts well and doens't hit anything. I don't have a hole for the shifter since my car was a 4 speed, but I will drill one and make a stay to hold the shifter in place. Then I'll make a bracket for the tranny and be done with it.  I would love to see a 5 or 4 speed up close though so if Brian from Apex can shoot me a email that would be fantastic!

Ron

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 Posted: 07-23-2005 06:06 am
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Judson Manning
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Ron,

The heavier Gauge bracket is actually the 4sp "anti-pole-vault" plate.  It cradles under the tail end of the 4sp transmission to catch the yoke in the event of a U-joint failure.  It is also a nifty stiffening member! 

I'm thinking the 5sp w/ original 2-piece drive shaft has the intermediate bearing mounted where the 4sp "anti-pole-vault" plate mounts.  When using the later 1-piece drive-shaft, the "anti-pole-vault" plate is in the way and must be eliminated.

Judson

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 Posted: 07-25-2005 01:12 pm
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Mitch Ware
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I left the anti-pole vault plate in mine with the one-piece driveshaft and 5-speed. There have been no interferance issues in the 4k+ miles I've driven it as far as I can tell. No scratches in the paint on the shaft, no wear marks on the plate and no scratching/grinding sounds during driving.

Mitch Ware
1974 JH-5 #111119670
1971 TR-6 #CC66950LO

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