Gearbox rebuild - popping out of 2nd advice? Video

[Andrew1]

Hi Team:

A video for gearbox experts to check out.

It's been a while since I posted, but with the cold Toronto winter, I decided to tackle a rebuild of my BJ8 gearbox today. I've run into a crossroads after getting 3/4 of the way through disassembly.

The problem the prompted the rebuild, was a perpetual slipping out of second gear, when decelerating under engine brake or downshifting from third to second.

I have followed posts on the forum and Hayes manual and have gotten as far as removing the 1st motion shaft, reverse shaft and layshaft from the case.

I was pleasantly surprised at how good a condition all the components are in, with no apparent wear/chipping on the visible parts of any of the gears.

Even externally the Syncro rings look great and sharp. Now, I am pausing to see if anyone can offer some advice on the 1st motion shaft before I start taking it apart unnesesarily. I have even prepared a video to help....

https://www.youtube.com/watch?v=Dwb5YsiprSs

(excuse my comentary, I got the 1st motion shaft and main shaft mixed up)

Issue 1:

Is the movement engaging the detents in the first gear assembly normal as I move it up and down or is there too much play? Or, as an alternative explanation, is it possible that the springs in the 1st gear assembly are a tad weak? Or, is it possible that the selector springs for the selector shaft/fork assembly are too weak to hold the gearbox in second?

Issue 2: From the video, is the orbital end play of the Main shaft too much? Should that main bearing be replaced?

Thank you for having a look at the video and posting your thoughts!!!

Andrew

 

[anthony7777]

andrew1, just watched your video, the end ply of the first gear sliding hub is normal,if you remove it from the shaft and you slide those sections apart youll have three ball bearings and three springs some place on your shop floor,its movement seems to be "crisp", however the movement of the the main shaft through the bearing is not good , that bearing is bad or the shaft is worn, has this trans. been rebuilt before? also did you remove the bearing on the first motion shaft from the housing/case easily? p.s. im only an expert by involvement.

 

[Andrew1]

No, Anthony this is the first rebuild of the gearbox and the mileage is approximately 60,000 miles. The 1st motion shaft bearing was very tight and took a few taps with a soft faced punch. There is no play with that bearing at all. In terms of it popping out of second, do you have any ideas where I should look?

Thanks again!!

- Andrew -

 

[Dave Russell]

Re: Gearbox rebuild - popping out of 2nd advice? V

The problem the prompted the rebuild, was a perpetual slipping out of second gear, when decelerating under engine brake or downshifting from third to second.

I have followed posts on the forum and Hayes manual and have gotten as far as removing the 1st motion shaft, reverse shaft and layshaft from the case.

I was pleasantly surprised at how good a condition all the components are in, with no apparent wear/chipping on the visible parts of any of the gears.

Even externally the Syncro rings look great and sharp. Now, I am pausing to see if anyone can offer some advice on the 1st motion shaft before I start taking it apart unnesesarily. I have even prepared a video to help....

https://www.youtube.com/watch?v=Dwb5YsiprSs

Issue 1:

Is the movement engaging the detents in the first gear assembly normal as I move it up and down or is there too much play? Or, as an alternative explanation, is it possible that the springs in the 1st gear assembly are a tad weak? Or, is it possible that the selector springs for the selector shaft/fork assembly are too weak to hold the gearbox in second?

Issue 2: From the video, is the orbital end play of the Main shaft too much? Should that main bearing be replaced?

Thank you for having a look at the video and posting your thoughts!!!
Andrew

Hi Andrew,
Your pic shows the first gear hub moving freely on the main shaft. The hub itself should be secured to the main shaft with a spring & detent so that the hub itself has no totally free fore/aft movement. These gear locating plungers are shown in the Moss catalog as #031-252 & 329-525. I'm not sure what the #442-100 & 442-110 springs & plungers do. I think it should be set up so that the inner hub moves first against it's detent to operate the 2nd gear synchronizer & then the outer sliding gear moves on it's detent to lock the hub to 2nd gear. The ball detents you mention only affect the outer gear which slides on the hubs outer splines.

I suspect that for some reason the 1-2 hub is not properly restrained on the main shaft. This could explain the failure to stay in gear. I'm not really sure on this so proceed accordingly. Hope someone else has ideas, The BJ8 is different from all earlier transmissions.
https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28882

The 3-4 gear should operate in a similar manner except it has synchronizers on both ends. If 3-4 works ok, compare it to the operation/feel of 1-2.

The radial movement on the front of the input shaft appears to be acceptable. When you consider that this movement is at the very end of a long shaft it is really not very much movement in the bearing. Besides, the front of this shaft is running in the pilot bearing in the crankshaft.
D

 

[Richard3000]

Re: Gearbox rebuild - popping out of 2nd advice? V

Hi Andrew,
can only tell you about the BT7 side change box. here jumping out of 1st or 2nd (or jamming in reverse) is normally due to a bent layshaft. The central change box was strengthened in this respect with bigger or more needle rollers, so this may not be your problem. On a BT7, accelerating hard in 1st gear is not a good idea.

I agree the movement on the input shaft is OK. As Dave Russell says it has the pilot bearing at the front. Also the needle rollers to the mainshaft are at the rear.

Richard

 

[Andrew1]

Re: Gearbox rebuild - popping out of 2nd advice? V

On the subject, can anyone explain what the plungers do on the sliding gear hub mechanism. They are Moss Part 44 329-525.

-Andrew-

 

[anthony7777]

Re: Gearbox rebuild - popping out of 2nd advice? V

Andrew, im doing what i remember to be my 6th healey trans. rebuild all with success, one of the trans. had the same problem as yours, i resolved it by replacing the three springs and detent balls p.n. 329-040. on the selector shafts, and also changed out worn selector forks. i still dont like the movement of the shaft through that end bearing mine does not do this and for under $30.00 id replace it. i took my time shopping around and bought everything either brand new or nos. nothing rebuilt or remanufactured. one of things i dont remember is the plunger you mention, since mine is still on the bench ill try to make some time this evening and refresh my memory, as i recall there are a couple of things different in a bj-7 and bj-8 set ups, one being a caged bearing p.n. 031-238 in bj-8, and needle bearings used for this in bj-7. one word of advise do not attempt to move/slide/reposition any of the gears with any hard object i.e. a screw driver, the gear sets appear to be stout but they are very brittle and easily damaged.

 

[Andrew1]

Re: Gearbox rebuild - popping out of 2nd advice? V

Thanks Anthony!

I will replace that main bearing since I have it all apart. And thank you for the advice about not damaging the gears.

In the o/d filter basket, I did find a moderate number of brass/bronze filings suggesting that it might be a a bit of meat off one of the selector forks.

Although, from the initial examinations, they look pretty good. It does not appear that the 1/2 selector fork is available from moss or victoria.

Any suggestions on replacement sources at a modest cost?

- Andrew -

 

[anthony7777]

Re: Gearbox rebuild - popping out of 2nd advice? V

andrew, the "plunger" we spoke about is exclusive to the bj-8 so i dont have it in the bj-7, a quick look at the part breakdown told the story, the selector forks do show up on ebay but you realy cant tell what condition they are in by the photos all used items and expensive, ive never seen a n.o.s. set or inividual piece up for sale, that doesnt mean there not around.

 

[vette]

Re: Gearbox rebuild - popping out of 2nd advice? V

Hello Andrew, i guess I'll throw in my two cents even though I have hardly any expertise on Transmissions. Since you mentioned some bronze filings in the filter. It seems to me that over the years i have been told that the trans popping out of gear on deceleration is many times caused by a worn bulk ring (syncro). I had an original '32 Ford years ago that did just that in 2nd gear. I had transmission checked/rebuilt, and the only thing that the guy replaced was the syncros and that solved the problem.

 

[Stretch]

Re: Gearbox rebuild - popping out of 2nd advice? V

I would look at the condition of the teeth on the gears. If a bevel has developed from wear then there could be a tendancy of the gears to try to push apart. There is not alot of bite for the sliding hub on the narrow teeth on second gear. It's hard to see the condition of the sliding hub teeth without taking the gear apart. (If you do make sure you reassemble the sliding hub onto the inner gear in exactly the same position). The teeth acquire a set and if rotated 120/240 degrees can jam during operation. If the shifting fork is worn, bent, displaced on the selector shaft or worn at the point the selector lever engages you may not be fully engaging the gear. Parts 442-100 & 110 simply retain gears on the mainshaft. 329-520 & 329-125 hold the sliding gear in a central position when first or second is not engaged. I believe the plunger you mention, unique to the BJ8, was developed to help reduce instances of jumping out of gear. Without taking the assembly apart I don't know how you could judge if wear is causing your problem. It really isn't too bad to disassemble and reassemble the mainshaft.

 

[Dave Russell]

Re: Gearbox rebuild - popping out of 2nd advice? V

Since you mentioned some bronze filings in the filter. It seems to me that over the years i have been told that the trans popping out of gear on deceleration is many times caused by a worn balk ring (syncro).

Although the synchros might be worn, they are made of steel on the BJ8's & would not be the source of bronze filings.
D

 

[bob hughes]

Re: Gearbox rebuild - popping out of 2nd advice? V

Just to add my weight in on the movement of the first motion shaft, having recently changed the clutch on my BJ7 the movement was much the same, and was deemed acceptable by a work shop. It takes a bearing at the front end, on a bush in the end of the crank so that helps steady it. Having said that, the bush was only part way home in the crank and was severley worn - - on the outside surface.
I would strongly recomend that you check and replace the bush and the driven plate of the clutch while you are at it.

As to your gear box problem, it is all a mystery to me, you are a brave man.

Bob

 

[anthony7777]

Andrew, how are you doing with the rebuild, you said you had some bronze/brass material in the filter each end of the lay shaft has a bushing made of this material check for end play on the lay shaft, i purchased n.o.s bushes for both ends the larger of the two cost $55.00 forgot the price of the smaller one, i sat down Thursday afternoon to finish up my rebuild when i tried to fit the first motion shaft onto the the end of the main shaft with 18 new needle bearings it would not slide on, some of these shafts take 16 needle bearing so i tied that still no go, i then remembered the bearings i removed had been thinner then the new set the ones i removed were the same used on the lay shaft so i called john at quantum mechanics in Monroe ct, told me to come over with my parts so he could check the numbers he confirmed i had all the correct parts he tried to refit the shafts also a no go, he put a caliper on the end of the the main shaft as i had done to check it, it was the correct size as he slid the caliper down the shaft it got stuck near its end, with a strong magnifying glass and light we found an otherwise discernable dimple probably caused by someone either dropping it on the ground or smacking it with a hammer thus the reason for the previous rebuilder to have used the incorrect layshaft bearings, got home and used a dremel with fine stone polished with some wet paper and all is now well in healey land, interesting project.

 

[Andrew1]

The rebuild is in a bit of a pause Anthony. My layshaft appears perfect with no play. The problem I am having now is removing the rear bearing and the bearing housing from the main shaft.

With all the spacers and O/D cam, and retaing rings removed... I can't convince the bearing and its housing to pop off the mainshaft.

Any ideas??

Once, I get this off, I can address the 1st / 2nd gear cluster.

- Andrew -

 

[anthony7777]

Andrew, i used two 5/8" inch bolts 12" long with nuts and washers and a flat piece of aluminum with three holes in it, a center hole large enough to fit over the first section of the end of the mainshaft a 3/8" hole on either side of it to slide the bolts through and into holes in the case tightening up the bolts compressing the shaft into the case releasing it from the bearing, removing the bearing from the case was a matter of "sacrifice" i didnt have the correct puller and was going to change the bearing anyway. you will have to remove the shaft in the lay gear so it falls out of the way, and also remove the reverse gear.

 

[Andrew1]

Re: Gearbox rebuild - popping out of 2nd advice? V

Hi Vette...

I checked the syncro rings and on my BJ8 they are made of steel, unlike the earlier cars. In fact they are perfect.

I suspect that the filings are from the 1/2 nd gear selector fork, which I can't seem to find a supplier. If there is anyone that can suggest a source.... that would be great.

- Andrew -

 

[healeynut]

Sounds to me like your box is missing the three little detente balls and springs, this will cause the symptoms you describe.

 

[anthony7777]

Sounds to me like your box is missing the three little detente balls and springs, this will cause the symptoms you describe.

healey nut, this is true, also even if the balls are there some weakening of the detent ball springs will also cause this problem, i just replace them.