tranny issues

75pinz · Post by **75pinz** » Mon Apr 02, 2007 8:08 am

I had more trouble ordering the part than changing it. I wasn't sure what it looked like inside, SAV couldn't understadn what I wanted, etc. Dennis luckily sent me one out. Mine was the one on top. I didn't even check the one on the bottom. I figured there was one down there. May want to look at that todd.

todds112 · Post by **todds112** » Mon Apr 02, 2007 4:14 pm

Definitely on the list. Thx.

Jim LaGuardia · Post by **Jim LaGuardia** » Mon Apr 02, 2007 5:06 pm

While I have changed out a few broken pivot pins in several trucks, it is not always the same pin, and there are 3 lenths depending on pin location.

Not something you really need to worry about until it happens(if ever)

Most of these trucks are ready to go just about anywhere , anytime

lindenengineering · Post by **lindenengineering** » Mon Apr 02, 2007 8:40 pm

Gents
My pet theory on why speeds Rev and 1st suffer from pivot pin failure is due to the design and use of the selector fork assy for that application.

Firstly 1st is synchro controlled so you could be putting undue force on the pins to engage that gear; This would be especially so when grabbing that speed on the trail for a quick get up and go (moreso when you are about to go backwards!)

The selector fork is a short stubby affair (due to the compact design) compared to the rest so more effort is needed to select. The rest of the gears bar 2nd are selected on the move so less syncho speed correction is normally necessary (unless you are doing something crazy!) Besides the selector fork for speeds 2-3 and 4-5 are much longer physically and the fulcrum points are longer top boot. (though not interchangeable).

Some transmissions/operators (sorry gearboxes) do show a propensity for failure whilst others no not. I have not been able to correlate this but it may in the end be a clutch problem or just ham fistedness ! (or lack of mechanical sympathy as my college lecturer would state many moons ago. )
Dennis
Dennis

mjnims · Post by **mjnims** » Mon Apr 02, 2007 9:40 pm

unfortunately in my case the truck is fairly new to me so I don't know how the previous owner drove it. I suspect by the way the pin looked it had been broken for some time. I suspect the other is broke but won't have time to look into it unti next week.

milesdzyn · Post by **milesdzyn** » Mon Apr 02, 2007 10:24 pm

Don't know if this may be the cause for some but just throwing this tidbit out. Lots of people downshift with the manual transmissions all the way down to 1st gear which may be fine for some trannies with standard gearing ratios. But from what I can tell the Pinz trans has a very short first and should not be down shifted into 1st gear.

Miles

lindenengineering · Post by **lindenengineering** » Mon Apr 02, 2007 11:29 pm

Miles
In many case you are right!
I don't use 1st gear at all unless its to do some form of slow movements that need torque like:- Pushing a semi truck into the shop with a Pinz. A nice piece of 3" straight exhaust pipe about 10' long suitably deformed at the end fits nicely in the front receiver and shoves big trucks across the yard with ease, once you have the spring brakes released!
Dennis

milesdzyn · Post by **milesdzyn** » Mon Apr 02, 2007 11:53 pm

Dennis...just to clarify, by down shifting I ment engine braking to slow down. I allways start in first even when I could start in second, just force of habit, plus it saves on the clutch.

Miles

todds112 · Post by **todds112** » Mon Apr 02, 2007 11:59 pm

Can someone please post a pic of where these are on the tranny. Even studying the parts and repair manuals I don't where they are.

milesdzyn · Post by **milesdzyn** » Tue Apr 03, 2007 12:24 am

Todds112...Look at Group 2-20 Page 17. The parts are #7(x1) #11(x4) #17(x1)

They are the guide pins for the 3 selector forks. Hope this helps.

Miles

todds112 · Post by **todds112** » Tue Apr 03, 2007 12:52 am

milesdzyn wrote:Todds112...Look at Group 2-20 Page 17. The parts are #7(x1) #11(x4) #17(x1)

They are the guide pins for the 3 selector forks. Hope this helps.

Miles

Yeah I saw those, but where the heck are they actually on the tranny? When I crawl under there is it pretty obvious?

Profpinz · Post by **Profpinz** » Tue Apr 03, 2007 1:09 am

Hope this helps

That is the input shaft (front of the gearbox) in the pic .....obviously with the bell-housing etc, removed.