915 trans rebuild questions

[emarsh]

Hi,

I pulled my 915 transmission apart and have a question before I order parts.

Basically, things look decent except that the synco dog teeth on first gear have been banged off. Evidently they are a replacement item, which is good since I don't want to have to replace the first gear matched set which I'm sure will be very $$$$!

I'm going to order a rebuild kit which includes syncros, gaskets and the firstgear dog teeth.

My question is how tough is it to replace the dog teeth? Should I just take the gear to a shop somewhere and have it done?

How about pressing all the gears apart and back together?

Thanks,

Eric

[Jim Sims]

"except that the synco dog teeth on first gear have been banged off" If this is the case you likely need to replace the 1st/2nd operating sleeve as well as the 1st gear dogteeth. There is a lot of information here on rebuilding the 915 transmission; do a search using "915" as the key word. Jim

[john walker's workshop]

better replace whatever else is worn while you're in there. i bet the other syncros are showing some polishing, and the 3rd/4th shift sleeve is worn out, amongst other things. check the thrust plates to see if they are allowing the ball bearings to have end play. second teeth should be replaced too, as they tend to drop teeth just like 1st. you don't want to tear it down again a year from now for 2nd gear.

[ohecht]

I just did this as a novice, and it is easy to get the first dog teeth replaced.

The gear will almost lift right off, the most I had to do was lightly pry with some screwdrivers.

I went around and around considering the special tool, but I could not justify the cost for one gear and for a tool that only does first and second. The hammer and chisel method scared me, but it was easy and took less than 10 minutes once I finally just went out and started hammering. I sacraficed a wood chisel, but you can use a cold chisel that is more durable.

JW has described the procedure well in many other threads. What got me is that the gap between the teeth and the gear is almost invisible ( you want to hammer right where the teeth are, with the flat part of the chisel against the gear and the chisel "ramp" lifting the teeth away from the gear), and it is hard to believe a chisel could even get in there and move anything. The space gradually opened, though, and then it really started to move and just fell right off. The gears are almost indistructible to these sort of forces, I think, so don't be shy with the hammer, as long as the chisel is straight.

I pressed on the new teeth with my cheap 12-ton press, but it should not be hard being careful and creative with hand tools, or a machine shop could do it faster than writing up an invoice. I was most worried as I pressed the teeth back on, because with my luck the gear would have snapped in half!

Hope this helps, beginner to beginner. I agree with Jim that you should also replace the sleeve, it is easy to inspect.

Olivier

[johnsjmc]

I just did the same rebuild. The dogteeth are easily removed with a wood chisel and installed with a wood block and a hammer. I would bet you are talking about the Motor Meister rebuild kit ( syncros gaskets and first gear dog teeth) They will be out of stock on the kit as usual and will upsell you on more expensive replacements Their operating sleeve was $250+ compared to Pelican at $145 ish. If you are on a budget you can flip over the syncros on 3,4,5 and just order 2 or 3 gaskets and skip the seals if they aren,t leaking but you may be wishing the trans had a zipper if you are unlucky. It,s fairly easy but take lots of pictures if inexperienced.

[Zeke]

Originally posted by johnsjmc
........but you may be wishing the trans had a zipper if you are unlucky.

I seldom laugh out loud at the computer while home by myself. That is too funny. And, I'm cracking up still.

Where, oh where can I get one? Can I get a zipper around the whole engine and just unzip it to drop it? Heh he he.

[emarsh]

Guys, thanks for the tips. I'll make a checklist of all the things you guys mention and make sure to do them all.

Eric