915 tranny rebuild

[mmasse]

This Saturday I started with my tranny rebuild...after doing a LOT of reading on this board!!. It's a '73 Mag case.

Some background on the tranny. I bought this tranny from a fellow Pelicany (Kamalea, great guy to deal with!!). The tranny was partially disassembled when I got it, and the PO didn't have much info about it except for the statement of the person he got it from (with a car without engine) that the tranny had no issues. The seller mentioned to me that he trusted the person he got it from given that everything he told him about the car was truth. He didn't need the tranny because he already had one with his engine.



I took it apart this weekend and went through the parts in detail. It seems that the tranny had been recently rebuild since all the synchro rings, dog teeth, brake band look like new. I compared the parts side by side with some brand new parts I had and there is no difference.

I did find some parts that showed some wear, the sliders. My assumption is that the mechanic who did the rebuild did not replaced the parts at the time of the rebuild, in order to keep costs down.

I plan to exchange the sliders and then dedicate some time to beef the tranny up, since it is going to work with a 3.6 993 engine.

My plan is a one piece bearing plate, reinforced side cover and cooling w/internal spray bar....it's going to be fun.


Any particular advice on what else to check/ do.

I am thinking about the internal shift gate, but it is quiet $$$. Is it worthy?!?!

I will try to get a better camera, since this pics were taken with my phone camera, but I think it ios enough to notice the wear on the slider, as well as the condition of the dog teeth.

[len911]

I'm not an expert, but I'm in the middle of doing my second 915 rebuild. See how the teeth have an indentation like a "half moon", that indicates that they are worn. I remember reading it on one of the rebuild posts, but just experienced it on the second rebuild. Teeth should also be sharp. I'm sure some of the experts will chime in. Good luck! It is a fun project... Lou

[Bobboloo]

Here's a good thread, in case you didn't come across it in your search, that documents the whole rebuild process by Jim Sims.

All the Way Into 915 & Comin Out (Long)

[gold911]

Here is another good link
http://www.pelicanparts.com/MotorCity/marcesq3/TrannyRebuild.htm

[Joe Bob]

Add the WEVO intermediate plate add on.....check the bearing race as well....

[Walt Fricke]

Alas, Mario

I'm with Len. Those dog teeth look, if anything, worse than the slider teeth (making allowances for the camera/photo). I'd replace them. Both have banged against each other too many times, it would appear.

So the most that was done was maybe to replace the synchro rings, I'd venture. And who would do that and not realize that these other parts were at or a bit beyond the end of the road?

In your adventures in Internet and Pelican Land, keep your eyes open for mention of, I think, 930 synchro retainer rings. I haven't upgraded to them, but I think others have. Might be useful in corraling the mighty 3.6s torque.

My personal opinion is that there are other things more useful for you to spend your money on in this tranny than the internal gate shift system. Though if you can afford everything, have at it.

Walt

[mmasse]

Could anyone help me with advice on how to press the synch ring out? I read that you could do it with a chisel but how do you support the gear in order to hit it with the BFH??

I used the chisel method with 5th gear and it was easy because the synch ring is larger than the gear so I could rest the synch on a vise and drive the gear down, but for 1st and 2nd the gear is larger than the synch ring and I can not figure out how to support it.

Thanks in advance

PS sorry for the bad pic!!

[Walt Fricke]

Mario

1) The best way is to purchase the two tools you can use to press out and back in the two sizes the 915 uses. These are not that expensive (compared with what else you will spend). I have never regretted buying a set even though I might use them once every 4 or so years.

2) Within the last day or two I read right here on Pelican of a low buck equivalent: use the stamped steel parts from two muffler clamps to grip the groove of the dog teeth, put the thing in a vice supporting long bolts replacing those from the clamp (after adding some nuts), and use a suitably sized socket (and hammer)to drive the gear out from under the dog teeth. This is basically what the proper tool does. I don't know how those skinny bolts held up to this, but the poster said it worked for him.

3) Use heat on the dog teeth. This certainly works for reinstallation of new teeth - deep freeze the gear, heat the teeth.

4) To remove, cut the old dog tooth part with a Dremel.

I have only used method 1), but believe the posts from those who have used the other methods.

I barely dare mention the 5th alternative: take the gear to a shop which has the tools and have them do it.

Walt Fricke

[mmasse]

Thanks Walt.

I got some drawings of the tool from another Pelicany and I will have it make here. I got a quote of less than 1/3 of the cost of the tool...and that's without shipping (which could be considerable in my case)

I will let you know how it turn out.

[chris_seven]

I have fitted Wevo internal gate shift systems into 915 boxes and found them to be very good especially when combined with the Wevo shifter.

I also think that there is now a lube system available from Wevo.

[gold911]

For what it is worth and I am no expert, I removed mine easily by setting the gear on its end tapping the chisel between the gear and dog teeth. I worked the chisel around the gear and they came off with no issues.

[mmasse]

I just got the tool from the shop. It costed me $25...quiet a discount vis a vis the price of it!!

Chris, thanks again for the drawings.

Now, I am ready to press the dog teeth out.

[mmasse]

Follwing some advice on this forum, I have decided to update the first gear setup to the asymmetrical type (1977)

I already bought the following parts:

1st &2nd Asymmetrical slider
Shift Guide (three legs part)
1st asymm. dog teeth
Brake band ans anchor and stop blocks.

My question is: do i have to change the brake band, stop and anchor blocks for 2nd?

when i looked in PET it seems that there are to versions of the brake band: regular or doble brake band.

I am not sure which wnat I should use.

Thanks in advance

[mmasse]

An update on my rebuild.

It is taken some time, mainly due to shipping time for the parts to Guatemala.

I am replacing all synch, and dog teeth. I have also replace dog teeth, synch ring, brake band and anchor blocks for 1st and 2nd, since I have converted to assymetrical 1st gear. For the 2nd gear I have choosen the updated 1-piece brake band, to match my new 1st gear.

Here is a picture of my 2nd gear with only the snap ring missing.



I am also replacing the retainer bearing plate with a 1-piece 930 piece, following the advice of PHII.

I am replacing all bearing (LOTS of $$$), but giving that this tranny will work with a 3.6 engine I thought it was worth to do it now. I also glued all bearings to the cage with Loctite 640, to minimize the potential for the bearings to get loose in the future due to the torque of the engine. There were no signals of them being loose now, but ...

I am also replacing the side cover with a reinforced later type cover, and with new differential housing bearing and seals.

As a side project, I am building an oil cooler system for this tranny. I have already fabricated an internal spray bar, based on the OEM design, and will complete the desing with an external Tilton pump and oil cooler. Separate thread Transmission cooler

[mmasse]

I need some help for the reassembling. These are the two bolts that were originaly on my case for the side holes where the detents go.

I dont recall which of them goes in which hole. Moreover, in looking at the manual and other posts here in the forum I started to doubt if there is any reason why they are different. Could anyone let me know if these are the right bolts, and if so where to put each of them?



These are the holes I am refering to

[sjf911]

This is what I show from my rebuild (later model 915 from and '83).

[mmasse]

Thanks Steve. that's but I thought. I guess the wrench who rebuilt the tranny before just put whatever was around that fitted in the holes!!

[Walt Fricke]

Steve - you saved me from feeling guilty for not going out to the garage and pulling one of these from my spare tranny. I knew at once, as you did, that someone had put some wierd stuff into Mario's transmission.

The one with the rod in the middle is especially unusual - wonder where that came from? If the little rod just fit inside the spring, I suppose it would work. But those stiff stubby springs don't seem to need any help.

Walt

[sjf911]

It is truly amazing what even "Porsche" mechanics will do. I have found a number of similar shoddy repairs on my car.

[mmasse]

What type of wrench/socket should I use to torque the big nut on the input shaft. If I am not wrong, it shoulfd be torque up to 168lbs/ft, right?

Thanks