Need Help Shifting Problem


New Member
Dec 19, 2015
I just got a 1990 fifty less then a week ago and my 3rd and 4th gear won't engage like if it's on nuatrual but my other gears will go catch. And when I hard shift 1st and 2ND won't go in it will grind but if I shift it soft it goes in there with Lil grind 5th ND reverse goes in smooth with no problem. What can cause this to happen?
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StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
Dublin GA
Since you didn't mention problems getting into first gear from a standing start, I would rule out problems with the clutch not disengaging properly.

It sounds like you have some serious internal problems with the T5. However some input from other sources would be helpful


i'm familiar with penetration
Mod Dude
Feb 18, 2001
3rd an 4th are on their own synchro in the trans. Unfortunately, I think that transmission is going to need to be opened up.


SN Certified Technician
Aug 27, 2012
In the garage
FIrst thing i sto check the fluid- is the trans full and what does the fluid look like? It sounds like one or a combination of

bent forks
bad gears
bad syncros

Time to open up the case for an inspectiom


StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
Dublin GA
I don't know how you feel about the DYI thing when it comes to gears, some people don't like the idea of working on transmissions. If the DYI transmission fix idea isn't something that you would rather leave to someone else, here are some resources:

See Tremec to download a FREE service manual for T5 or Tremec 3550/TKO
You will need the Adobe Acrobat viewer which is also a free download – Adobe Acrobat Reader DC Install for all versions

See Welcome to Hanlon Motorsports! | Hanlon Motorsports or D&D Performance for parts

A T5 rebuild kit with syncros, bearings and other small parts costs about $160-$200. It does not include any gears or shafts.

Welcome to Hanlon Motorsports! | Hanlon Motorsports also has a video on how to rebuild your T5 or Tremec. It costs about $20, and is worth every penny of it.

I did a Tremec 3550 rebuild, and it wasn't that difficult. The video was an immense help, and I would recommend viewing it. At $20, it will give you an opportunity to look and decide for yourself if you think that it is something you want to try to do.

Alternate sources for the T5 rebuild video...
t-5 transmission rebuild video - Google Search

T5 Shim kits – best product I have seen in a while… T5 World Class 5 Speed Shims
“The Peel ‘n Place T5 World Class shim kit makes shimming T5 counter gear and main drive gears very easy.”

For Tremec 3550 and TKO's:
You will also need a magnetic base and dial indicator to measure the endplay ($40-$120). MSC Industrial Supply Co. | Find Power Tools, Hand Tools, Machine Tools & More P/N 06444129 cost was approximately $57 + shipping as of Feb 2013

The tricky part is that you will need some shims to adjust the endplay in the two shafts: the new bearings will change the clearance. There is no way of telling what it will be until you get to the point that it is time to measure and check the clearances. Halon has the individual shims if you can wait for them. If you can't afford the wait, the auto parts store can sell you some shim stock and you can make your own, or have a machine shop make them for you. The shim stock comes in brass (easy to cut) and steel, in varying thicknesses. That's where the dial indicator & base come in - there is no way to get the clearance right without it.

Getting the car jacked up high enough to get the trans jack in and out from under the car was somewhat challenging. Since I didn't have a helper, getting the trans out of the car and back it was one of the more difficult things about the job. I built a trans jack out of 2x6's, some angle iron and a $25 floor jack. If I hadn't done that, I would have needed a helper or to rent a commercial trans jack. At 100+ pounds the Tremec 3550 was far too heavy for me to lift by myself.
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