HELP! Broke something in T56
10-20-2008, 11:09 AM
#1
On The Tree
Thread Starter
iTrader: (2)
Join Date: Jul 2008
Posts: 181
Likes: 0
Received 0 Likes
on
0 Posts
HELP! Broke something in T56 I'm new to the forum, so please bear with me.
The T56 in my 99 Z28 had been crunching going into 2nd and reverse and it started getting worse. It started popping out of 1st and it was getting harder to put it in reverse. The clutch master was low on fluid and I traced it to a leaky slave cylinder. So I pulled the transmission and tore it apart to check for further damage. I also found that the pilot bearing was destroyed.
I've been a mechanic for 15 years and have rebuilt many transmissions, but this was my first T56. I found the mesh teeth on 1st, 2nd, and 5th worn. 3rd and 4th weren't that bad. I replaced 1st, 2nd, and 5th gears, all the friction/blocker rings, 1-2 sychro assy, 5-6 synchro assy, flipped over the synchro sleeve on reverse, and all the snap rings. I put it together with no problems.
It drove fine from 1st through 4th gear. 5th gear would have an intermittent noise that sounded like a bad bearing. The noise would go away after about 2 seconds. The next day I drove it again. 5th made that same intermittent bearing noise. I put it in 6th and drove about 7-8 miles with no problems. Then a bearing noise started and it got louder for about 20 seconds and then BANG! I pushed in the clutch and coasted to a stop. When I let the clutch out, the car started going backwards! The shifter was in neutral! If I put the shifter in any gear, the car seemed like it was in forward and reverse at the same time.
I got my truck and trailer. I partially backed the car onto the trailer and then reverse let go. I put it in 1st and then was able to turn around and drive it onto the trailer. Now it sounds like I have a transmission full of gravel.
It'll be at least Tuesday before I'll have a chance to pull the tailhousing off to see what happened. Anybody ever hear of this before? How does a transmission spontaneously go into reverse when you're cruising along in 6th gear?!
The T56 in my 99 Z28 had been crunching going into 2nd and reverse and it started getting worse. It started popping out of 1st and it was getting harder to put it in reverse. The clutch master was low on fluid and I traced it to a leaky slave cylinder. So I pulled the transmission and tore it apart to check for further damage. I also found that the pilot bearing was destroyed.
I've been a mechanic for 15 years and have rebuilt many transmissions, but this was my first T56. I found the mesh teeth on 1st, 2nd, and 5th worn. 3rd and 4th weren't that bad. I replaced 1st, 2nd, and 5th gears, all the friction/blocker rings, 1-2 sychro assy, 5-6 synchro assy, flipped over the synchro sleeve on reverse, and all the snap rings. I put it together with no problems.
It drove fine from 1st through 4th gear. 5th gear would have an intermittent noise that sounded like a bad bearing. The noise would go away after about 2 seconds. The next day I drove it again. 5th made that same intermittent bearing noise. I put it in 6th and drove about 7-8 miles with no problems. Then a bearing noise started and it got louder for about 20 seconds and then BANG! I pushed in the clutch and coasted to a stop. When I let the clutch out, the car started going backwards! The shifter was in neutral! If I put the shifter in any gear, the car seemed like it was in forward and reverse at the same time.
I got my truck and trailer. I partially backed the car onto the trailer and then reverse let go. I put it in 1st and then was able to turn around and drive it onto the trailer. Now it sounds like I have a transmission full of gravel.
It'll be at least Tuesday before I'll have a chance to pull the tailhousing off to see what happened. Anybody ever hear of this before? How does a transmission spontaneously go into reverse when you're cruising along in 6th gear?!
10-20-2008, 11:36 AM
#2
Banned
iTrader: (60)
Join Date: Mar 2005
Location: Adkins - Tx
Posts: 2,693
Likes: 0
Received 0 Likes
on
0 Posts
You got something seriously wrong . Did you happen to have left the small snap ring off the reverse shift rail ? Maybe it slipped into reverse and then you put it into first gear at the same time ?
Either way , you probably have pile of $hit now not even worth rebuilding .
Either way , you probably have pile of $hit now not even worth rebuilding .
10-21-2008, 08:42 PM
#5
On The Tree
Thread Starter
iTrader: (2)
Join Date: Jul 2008
Posts: 181
Likes: 0
Received 0 Likes
on
0 Posts
I found the problem. It wasn't a snap ring. The roller bearing behind the reverse gear let go (seized up first). The reason why? The same reason why the transmission stopped going into reverse. I installed the reverse fork upside down! Pretty amateurish mistake. It also tore up the extension housing. If somebody would tell me how to post pictures, I'll show the damage. I'll tear it apart the rest of the way Thursday and see if there's anymore damage. Even if there isn't, I'm not sure yet if its worth it to replace the housing and bearings. Summit Racing sells brand new T56's for $2425.95 plus $109 shipping.
Trending Topics
10-25-2008, 09:41 PM
#10
On The Tree
Thread Starter
iTrader: (2)
Join Date: Jul 2008
Posts: 181
Likes: 0
Received 0 Likes
on
0 Posts
I was wrong. The reverse fork was NOT flipped over. Now, I don't know what happened. The caged needle bearing inside reverse gear was destroyed and it damaged the main shaft. At minimum, I'll need a mainshaft, reverse gear and the thick thrust washer, the caged bearing, the roller bearing behind reverse with the two spacers, a snap ring kit, reverse synchro assembly, reverse blocker ring, and the extension housing. I may need a new friction kit and bearing kit as well.
I checked prices at D&D and saw they had takeout mainshafts for $99. I assume these are shafts they pulled from other transmissions. They also have cluster kits with bearings for $599. That probably doesn't come with the mainshaft, does it?
I checked prices at D&D and saw they had takeout mainshafts for $99. I assume these are shafts they pulled from other transmissions. They also have cluster kits with bearings for $599. That probably doesn't come with the mainshaft, does it?
10-26-2008, 09:06 AM
#11
You should be able to call one of the sponsors or thegearbox and piece together and order of just the parts you need. The take-outs are used/working mainshafts from customers that have done the viper mainshaft upgrade.
When you orig had the trans apart, was the reverse synchro disassembled? I've ran across a few trans' that died like yours, when the rev synchro key retainer fell off and the rev slider was free to engage during some 5/6 shifting.
mike
When you orig had the trans apart, was the reverse synchro disassembled? I've ran across a few trans' that died like yours, when the rev synchro key retainer fell off and the rev slider was free to engage during some 5/6 shifting.
mike
10-27-2008, 07:49 AM
#14
On The Tree
Thread Starter
iTrader: (2)
Join Date: Jul 2008
Posts: 181
Likes: 0
Received 0 Likes
on
0 Posts
I thought I assembled the reverse section correctly - maybe not. I took pictures when I disassembled the damaged transmission. How do you post pictures? Maybe you'll be able to see something I haven't.
10-29-2008, 07:54 PM
#18
Teching In
iTrader: (11)
Join Date: Jul 2008
Location: goldsboro
Posts: 41
Likes: 0
Received 0 Likes
on
0 Posts
t56 hey man me and my good freind have been rebuilding these trannys for about 5 years. i've never heard of this happing but if you send my email some pics ill try to help you out.
