915 Questions

Porsche_monkey · 09:46 AM

My 84 Cab was very difficult to shift 1-2, and occassionaly popped out of second. Everything else seemed to be typical for a 915. I tried adjusting the linkage, no improvement, so the tranny is out.

This is where I am in disassembly:

I am guessing that the 1-2 synchro is the problem. Even tough I've read the 915 rebuild faq, I still don't really know what I'm doing.

Could someone please point out where I should be looking next? I'll dig into it and post detailed pictures, but nothing looks damaged, and there was no shrapnel on the plug.

Porsche_monkey · 04-04-2007, 11:32 AM

Well I know wher to go now. Do I remove the bearings (red) or the nuts next (purple)? Can I just pull the nuts off and remove as an assembly?

jess p · 04-04-2007, 11:46 AM

Before you go any further you are going to need a special tool and jig plate to adjust shifter before installing assembly back in the case. Usually, synchro's are bad when you cannot downshift
from 2nd to 1st. When you adjust the linkage on a 915 tranny
you place the shifter in first gear, remove the inspection cover
just in front of the back rear seats loosen the retaining nut and pull the coupler and shift rod snug and then tighten the retaining nut. Sometimes this has to be done several times to get it just right.
Are the bushings in the coupler worn!!! How about the cylindrical bushing in the bottom of the shifter. All of this must be
CHECKED BEFORE you suspect and remove the tranny.

76 911s
81 911sc
66 912 V8
71 914 PROJECT CAR

silverc4s · silverc4s's Garage

[QUOTE]Originally posted by jess p
[B]Before you go any further you are going to need a special tool and jig plate to adjust shifter before installing assembly back in the case. Usually, synchro's are bad when you cannot downshift
from 2nd to 1st. When you adjust the linkage on a 915 tranny
you place the shifter in first gear, remove the inspection cover
just in front of the back rear seats loosen the retaining nut and pull the coupler and shift rod snug and then tighten the retaining nut. Sometimes this has to be done several times to get it just right.
Are the bushings in the coupler worn!!! How about the cylindrical bushing in the bottom of the shifter. All of this must be
CHECKED BEFORE you suspect and remove the tranny.

I don't know if you noticed, but PBH has pretty much passed that point...

...

Porsche_monkey · 04-04-2007, 11:50 AM

Quote:

Originally posted by jess p
Before you go any further you are going to need a special tool and jig plate to adjust shifter before installing assembly back in the case.

I haven't seen anything abou that on Pelican....

Quote:

Originally posted by jess p
When you adjust the linkage on a 915 tranny
you place the shifter in first gear, remove the inspection cover
just in front of the back rear seats loosen the retaining nut and pull the coupler and shift rod snug and then tighten the retaining nut. Sometimes this has to be done several times to get it just right.

It's more serious than that...but that is where I started.

Quote:

Originally posted by jess p
Are the bushings in the coupler worn!!! How about the cylindrical bushing in the bottom of the shifter. All of this must be
CHECKED BEFORE you suspect and remove the tranny.

That is all done. It did not help. It's torn apart because there is sometting wrong inside.

This is a high mileage 915 (160,000 miles) it needs to be gone over.

cashflyer · 12:31 PM

If you remove the bearing girdle nuts (purple) you can remove both shafts with gears, and the shift forks as a complete assembly - and you will NOT need the special jig.
You should be able to pull it out like this:

You only need the special jig if
A) you have loosened the shift forks from their shafts, or
B) the shifting problem is due to misaligned or worn shift forks

cashflyer · 12:48 PM

Read through BOTH of these threads!
Can't Shift Into First
http://www.pelicanparts.com/MotorCity/marcesq3/TrannyRebuild.htm

Porsche_monkey · 04-04-2007, 12:35 PM

Well I have the nuts off, but it won't come out....

cashflyer · 04-04-2007, 12:44 PM

Make sure the sliders/shift forks (blue) are in their neutral position, and remove the two shift fork detentes (green).

The detentes should have the cap bolt, a spring, and a steel pin. Use a pencil magnet to remove the items and place in a ziplock bag until reassembly.

I really wish you had decreased that trans.

cashflyer · 04-04-2007, 12:46 PM

Keep in mind that when it does all come out, there is ONLY your hands holding it all together. And it's oily.

You may want to tie a shop rag around it all so to lessen your chances of dropping it all to the ground.

Porsche_monkey · 04-04-2007, 01:06 PM

It's apart. Just needed some help from a mallet. I'll post pictures in a few minutes...

Porsche_monkey · 04-04-2007, 01:19 PM

First gear looks a bit worn....

Porsche_monkey · 04-04-2007, 01:29 PM

These look a bit rough...

But these seem fine...

Suggestions....what to order?

cashflyer · 04-04-2007, 01:43 PM

Others may agree or disagree, but my suggestion is to replace everything that is questionable. This saves you down-time later.

jess p · 04-04-2007, 01:44 PM

[QUOTE]Originally posted by silverc4s
[B]

Quote:

Originally posted by jess p
Before you go any further you are going to need a special tool and jig plate to adjust shifter before installing assembly back in the case. Usually, synchro's are bad when you cannot downshift
from 2nd to 1st. When you adjust the linkage on a 915 tranny
you place the shifter in first gear, remove the inspection cover
just in front of the back rear seats loosen the retaining nut and pull the coupler and shift rod snug and then tighten the retaining nut. Sometimes this has to be done several times to get it just right.
Are the bushings in the coupler worn!!! How about the cylindrical bushing in the bottom of the shifter. All of this must be
CHECKED BEFORE you suspect and remove the tranny.

I don't know if you noticed, but PBH has pretty much passed that point... ...

It always amazes me that there are more POST WHORES
here than there are people who are willing and trying to help.
This is to you silverc4s, why don't you chime in and offer some useful advice. You strick me as a polisher and waxer, the
extent of your skills!!!!!!!

dlagerstrom · 04-04-2007, 01:51 PM

I just did the same thing. In fact, I don't have it back together yet!

I replaced the 1st and 2nd synchro bands, brake bands, dog teeth, slider and hub for the slider. That was about $1000.

Pelican has a nice gasket set for the 915 as well for when you want to put it all back together. I didn't degrease mine until it was all apart either. I have spent the past 3 weeks or so cleaning all the nooks and crevices with lots of blue paper shop towels, some engine brite, and small screwdrivers and plastic putty knives. Tons of work but looks really nice when done.

sjf911 · sjf911's Garage

Dog teeth and synchro rings at the least. I ended up replacing the entire setup like dlagerstrom. If you have the resources, getting the special tool to remove the dog teeth really makes a difference.
I highly recommend the two links posted above by cashflyer. They were enormously helpful to me.

Porsche_monkey · 04-04-2007, 03:46 PM

So I need to get :

930-302-411-02-M260 915 Slider, 1st/2nd, 911 (1978-86)
Brand: OEM [Photo]

915-302-301-06-M260 915 80mm Synchro Ring, 1st, 911 (1977-86)

915-302-301-04-M260 915 80mm Synchro Ring (sold per each), 1st, 2nd 911 (1974-76), 2nd, 911 (1977-86)

10-1550-312-M184 915 Synchro Hub, Asymmetrical 1st, 911 (1977-86)

Jim Sims · 04-04-2007, 04:10 PM

Also replace the 1st and 2nd gear brake bands. If you're already in there and given the high mileage I would also replace the 3rd and 4th gear synchro rings and brake bands if there are any polished spots on their surface coatings.

Porsche_monkey · 04-04-2007, 04:44 PM

Geez... you guys on commission at Pelican?

Okay I'll make a new list. Helping Wayne fund his F-car repairs...