Rebuild a Tremec 3550

[Zap's 85 GT]

A few months ago I bought a Tremec 3550 and bellhousing for $500. It needed about $410 worth of parts so I left it stored in a parts bin until I rounded up some money to buy the parts it needed. I was checking around on eBay a few weeks ago and a used but mint condition 1-2 slider(synchro) I needed was up for $50 buy-it-now. They normally go for about $280 so I snapped it up. The 3-4 synchronizer assembly I also needed I just purchased new for $130 at the same time. So I saved $230. Yey for me, for once.

I documented the rebuild process. Thought someone would find it informative. Now I have a tranny that's all good to go. Don't know what I'm going to do with it. Was thinking of putting it into the Mach 1, but for as much as I drive it, the Toploader just suits it more. Its always good to have some bartering hardware for whatever pops up down the road.

Tremecs are actually very easy to rebuild. You do not even need a shop press like you do when building a T-5.

Bin of bits. All clean and ready to go.


Tremec synchro/refresh kit I got with the transmission when I purchased it.


Worn 1-2 slider


Used but good 1-2 slider


Worn 3-4 synchro assembly.


New 3-4 synchro assembly.


Installed all new shifter fork pads.


Cleaning the case. Dont use a whiz wheel. These are precision machined surfaces.


Lots of needle bearings in Tremec's. Not as big of a deal as it seems.


Counter shaft installed.

[Zap's 85 GT]

This bearing is made a in Germany and is $150 to replace. Don't lose it.


Reverse gears and shifter parts installed.


5th gear bearing prepped for installation.


Comparison between a Tremec 3550 main shaft and a Tremec TKO main shaft.




Main shaft ready for assembly in a padded vice.


Main shaft bearing installed with retainers.


Caged needle bearing installed.


Spacer above caged bearings installed.


Gears starting to go together.

[Zap's 85 GT]

More assembly pics.














Cleaning the glazing off the gears from the old synchronizer mating surfaces.

[Zap's 85 GT]

Installing the main shaft into the case.




Input shaft needle bearings installed.

[Zap's 85 GT]

Input shaft installed with bearing race.


New input shaft seal.




5th gear shift fork installed along with speedometer gear.


Ultra gray silicone sealant. Little dab will do you.


Spread it around with your finger.


Torque the lid to 20 ft/lbs.


Old scored tail shaft bushing.


New bushing pressed in.


New tail shaft seal.


Big vice to hold one of these trannys. :-)

[Zap's 85 GT]

One last look before sealant.


Make sure you add the counter shaft shims and bearing race before installing the tail shaft and torquing to 50 ft/lbs.


Check main shaft end play. Shims will be adjusted in the input shaft bearing retainer accordingly.


Shifter installed.


Covers installed and all done.

[Mike Croke]

Nicely done.

[wman24]

Nice clean rebuild, looks good. Thought I read somewhere someone made fiber lined block rings, like a t5, for these. Then again I've never had a 3550 to even see how it shifted stock.

[82MustGT]

Thanks for the write up and pics. Nice job! I hurt my 3550 with the 347 I installed last year. Too much playing around, so I have to repair it now.

[Zap's 85 GT]

Nice clean rebuild, looks good. Thought I read somewhere someone made fiber lined block rings, like a t5, for these. Then again I've never had a 3550 to even see how it shifted stock.

They are like $75 each. I think tremecs shift fine. They are heavy duty transmissions, and not so much performance transmissions. think of them as a toploader with a 5th gear and an internal shifter rail. It's abuse that leads to their demise. The gears and bearings are quite bulletproof.

[cb84capri]

i see you have a very early 3550. you will have fun with that one leaking if you install it as-is. i recommend tapping a hole in the shifter base to install a vent. also, drive the front dowel out of the cover or the main case is bound to crack if put into service.

it looks nice though, i like the step by step pics.

cale

[Zap's 85 GT]

i see you have a very early 3550. you will have fun with that one leaking if you install it as-is. i recommend tapping a hole in the shifter base to install a vent. also, drive the front dowel out of the cover or the main case is bound to crack if put into service.

The shifter boot has a loose tolerances for venting. No need to install another. Pretty much just like an old toploader vent. Just a hole in a piece of sheet metal. This transmission was dry as a bone when removed. I'm not sure I've ever seen a leaking early Tremec and I've seen a bout 4-5 in action. From what I've seen its a myth. If a trans is going to leak, its probably from bad seals.

I don't know what dowel you are referring to? This trans has seen plenty of service in the past(two different cars, a fox mustang and a 351 fairmont wagon) and the case is perfect. I've only ever seen new cases having been cracked/repaired. Its all pretty much down to abuse and poor installation. Solid or poly motor mounts with stock rubber transmission mounts. Not using the proper transmission to bellhousing bolts. Using the bolts to snug the transmission to the bellhousing flange. No cage or subframe connectors in a big motor car with slicks. Using a scattershield that has not been blueprinted. Etc. So early cases being crack prone seems to be another myth I could dispel.

Tremecs live hard lives. Nobody puts them behind a stock 302 and goes the distance with them. Usually they hurt their T-5, buy the Tremec, stab it in then immediately go blasting around and wonder why it doesn't shift right. I personally love the 3550 I have in behind the 408 in my GT. Never missed a shift yet. You definitely need to shift it like a man until it breaks in. After that they can be just as streetable as a T-5.

[cb84capri]

i guess if you're only going to run the stock shifter on there you might be ok. i never have, maybe that's why mine pressurized and blew transmission fluid out of the rear seal until i got a vented lid for it.

i scooped my spare 3550 trans with a snapped main shaft. if was put through hell at the track. i think the only reason the case didn't crack on that one is because someone knocked the front dowel out of the cover. my first 3550 had a cracked main case, split straight down the side of the case from the front dowel hole. i can dig up a picture of it if you want. according to liberty's gears it was a very common problem with the early case.

cale

[Zap's 85 GT]

i guess if you're only going to run the stock shifter on there you might be ok. i never have, maybe that's why mine pressurized and blew transmission fluid out of the rear seal until i got a vented lid for it.

i scooped my spare 3550 trans with a snapped main shaft. if was put through hell at the track. i think the only reason the case didn't crack on that one is because someone knocked the front dowel out of the cover. my first 3550 had a cracked main case, split straight down the side of the case from the front dowel hole. i can dig up a picture of it if you want. according to liberty's gears it was a very common problem with the early case.

cale

I was thinking of converting it to a TKO. Just don't think its worth it for this unit. I already have a main shaft. All I would need to do is have the tail housing machined to accept the larger bushing and buy a 26 spline input shaft. If I ever break the one in my GT I'll probably save the main shaft for it. Seen more people bend/snap 3550/TKO500 input shafts vs outputs.

[cb84capri]

the break is pretty amazing, it looks like it was precision cut. it snapped right where the shaft necks down. the guy claimed the windsor in his fox was making 450 flywheel, and he broke it being greedy when he tried to leave on a 200 shot.

cale