Tremec 3550 reverse problem - help!

HI Cobra · #1 (**permalink**) 05-31-2007, 10:35 PM

Hope someone can help me here.
Very recently my Tremec 3550 is having a problem staying in reverse.
It just eases out when I am backing up and the only way I can keep it
there is to hold it in tightly. Everything going forward is fine - no problems
popping out of any gear. I've never ground it, missed shifts or abused it,
and got it new with the Cobra kit. I have close to 18k miles - but that isn't
much for a transmission for the way I drive, which is mainly to the North
Shore and back, about 80 miles round trip and mostly on our freeway.
The clutch is fine = no problems with it either.

Anyone else encounter a similiar problem, and if so, what fixed it?
Thanks for your help.

wtm442 · #2 (**permalink**) 05-31-2007, 11:19 PM

Disconnect the rubber boot at the floor and see if that is your problem. I had a boot that was too stiff and the tranny would not stay in 3rd gear.

HI Cobra · #3 (**permalink**) 06-01-2007, 12:42 AM

I have a leather boot that I sewed so I know that isn't the problem. I pulled
it and checked that the shifter was tight (it was) because it came loose a while back and gave me a scare but once I put one bolt back in, added lock wshers and tightened them both up no more problems there. It almost feels like it isn't quite going all the way in, so I have to hold it there to back up or it just pops out - no grinds. Everything else feels fine so I was wondering if
any one else had a similiar problem.

Jimi G · #4 (**permalink**) 06-05-2007, 11:55 AM

Do you have a aftermarket shift top on your 3550? If it is adjustable you might have to adjust the throw. jimig@standardtransmission.com

HI Cobra · #5 (**permalink**) 06-05-2007, 03:59 PM

As far as I know it is a standard Tremec 3550 with no changes.
This problem just started 2 weeks ago with no warning. At first it would
come out of gear if I didn't hold it in, now it feels like it is in when I put it
in but when I let the clutch out it feels like it actually isn't in and grinds if
I try to hold it in. All the other gears are solid - it is just reverse. It feels
like the detent isn't letting it go to the proper position. I'm going to try to
get to the cover without having to drop it tonight nand see what I can find out. To be continued...

HI Cobra · #6 (**permalink**) 06-22-2007, 10:11 PM

I pulled the transmission and discoverd it is not the 3550 but rather the
world class T-5 tag 1352-249. My mistake. I bought the set up as a crate
build and when I went back and checked my billing it was a T-5. It is fun
getting older! Long story short version - casing is bad, reverse gear is bad,
etc. and the estimate is $1,200 for a rebuild. Haven't found anything yet.
Checked ebay, one seller had one with the same tag # at $900, add shipping
and I'm back to $1,200. I'm trying to stay with the same so I don't have to start changing other stuff - clutch, pressure plate, drive shaft, etc. anyone
know of a similar tranny available or if something else would be an easy switch. I have a little over 400 hp & torque but don't slam it. The other lasted almost 18k miles and I think it may have been tired when I got it.
I have never had clutch or tranny problems in anything before so I don't
think it was me.

Thanks for your help.

Excaliber · #7 (**permalink**) 09-08-2007, 09:25 PM

Well Flip (Hi Cobra) got a good used T-5 and is back on the road, now I have the trans and am investigating the problem:

At this point it looks to me like the 5th gear shift 'pivot' point on the shift rail is the culprit! It's very loose, woobles around and tends to 'bind' when your trying to shift into reverse. That shift rail IS 5th and Reverse gear! The case itself is also worn allowing the shift rail to move around, but I don't think thats contributing much to the problem, all though it may in the future.

At this point this is just a working THEORY subject to further exploration and ideas, input welcome.

By the way, while reverse idler gear teeth are showing wear I wouldn't say it's a 'bad gear'. The wear seems fairly typical of what you would see on a 'straight cut teeth' no synchro type of engagement gear. Shift rail movement in the case is present, but not severe.

HI Cobra · #8 (**permalink**) 09-08-2007, 10:10 PM

Interesting. Looks like maybe a combination of loose parts adding up to
a problem. I remember it just started getting more difficult to get it to
"drop" into reverse, then I had to hold it in as I let the clutch out, then it
wouldn't stay in reverse no matter what so that is when I pulled it. So far
the replacement is working just fine, with about 500 miles or so on it.

DavidinDurango · #9 (**permalink**) 09-09-2007, 06:11 AM

Yep, you want to verify it is in reverse all the way.

Quote:

Originally Posted by Jimi G

Do you have a aftermarket shift top on your 3550? If it is adjustable you might have to adjust the throw. jimig@standardtransmission.com

Excaliber · #10 (**permalink**) 09-14-2007, 01:32 AM

Stock shifter, no adjustments.

UPDATE:
Sure enough, it WAS the loose pin for FIFTH gear that was causing the linkage to bind and preventing a full shift into REVERSE gear. I tightened up the pin/roller for 5th and it shifts very easily now.