T5- Z spec 5th gear problem

ndy846 · Jun 26, 2010

Hi, I have installed a brand new T5-Z spec in my Plus 8 Morgan (240 hp). Everything was Ok and quiet for the first 75 miles. When I took it out the next time as soon as I put it in 5th gear and put it under load, this loud rattling noise came from the gearbox. The other four gears are quiet. The shifter also jerks back (1/8" at the top of the 6" lever) quite violently but a few seconds after the noise starts. The noise is a loud whirring and sounds like someone gargling. Oil level is correct and ATF. The box is out of the car and all looks ok inside. Any suggestions as to the cause please?

jrichker · Jun 26, 2010

The snap ring on the countershaft may have popped loose...

You will have to pull the tailshaft housing off to fix it. In order to get the tailshaft off, you have to remove the shifter and the roll pin that secures the shifter rails. That means removing the trans from the car unless you have magic hands...

See TTC: Product Literature 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 - Adobe Reader download - All versions

See Hanlon Motorsports - T5 and Tremec parts, sales and service or Welcome to D&D Performance - The 5 & 6 Speed Experts! for parts

ndy846 · Jun 27, 2010

jrichker said:
The snap ring on the countershaft may have popped loose...

Thanks for your reply. I'm in the UK so expect a big time difference in the responses.

I thought it might be the snap ring but I checked that and it is still in place. Everything looks ok both inside the tail housing and the box itself. The 5th gear assembly seems very sloppy though and something on there must be kicking back to make the shift lever jerk back (as described in my post above).

With the syncro assembly engaged in 5th, I cannot understand what is causing the loud whirring noise.

MoggieOwner · Jun 30, 2026

ndy846 said:
Hi, I have installed a brand new T5-Z spec in my Plus 8 Morgan (240 hp). Everything was Ok and quiet for the first 75 miles. When I took it out the next time as soon as I put it in 5th gear and put it under load, this loud rattling noise came from the gearbox. The other four gears are quiet. The shifter also jerks back (1/8" at the top of the 6" lever) quite violently but a few seconds after the noise starts. The noise is a loud whirring and sounds like someone gargling. Oil level is correct and ATF. The box is out of the car and all looks ok inside. Any suggestions as to the cause please?

Hi, this is an old thread, but I will try. I have installed a T5 on my Plus 8. As you, all was quiet for a bit. Then, during a slightly longer trip, there was a bang coming from the gearbox and after that, load rattling under load in 5th. Tremec replaced the box. I am just back from the fist longer trip. No bang, but after about 200 milks, there is a distinct rattling in 5th under load. Not as strong as the first time, but enough that we drove back in 4th. Did you ever get your problem fixed?

General karthief · Jun 30, 2026

MoggieOwner said:
Hi, this is an old thread, but I will try. I have installed a T5 on my Plus 8. As you, all was quiet for a bit. Then, during a slightly longer trip, there was a bang coming from the gearbox and after that, load rattling under load in 5th. Tremec replaced the box. I am just back from the fist longer trip. No bang, but after about 200 milks, there is a distinct rattling in 5th under load. Not as strong as the first time, but enough that we drove back in 4th. Did you ever get your problem fixed?

This 'member' has not been back since 2010?
Have you communicated with Tremec about this new issue?

MoggieOwner · Jun 30, 2026

General karthief said:
This 'member' has not been back since 2010?
Have you communicated with Tremec about this new issue?

Not yet. Being in Portugal, I have to wait until office hours in Michigan. But I was also fishing for other people with Morgan +8s who have been down that road. Or other after-market fitters who may have experienced the same.

AeroCoupe · Jun 30, 2026

Does the transmission shift in and out of 5th with relative ease? Does it rattle at any rpm under load? I am not sure about the bang you heard but I did some searching and ran across a post by SPeace-ATL over on ffcars.com here:

https://www.ffcars.com/posts/3078353/

I would venture to say that he has rebuilt hundreds if not a couple thousand T5's and he helped me with an issue I was having on one of my T5's. Told me what he thought was wrong and absolutely nailed it.

MoggieOwner · Jul 1, 2026

AeroCoupe said:
Does the transmission shift in and out of 5th with relative ease? Does it rattle at any rpm under load? I am not sure about the bang you heard but I did some searching and ran across a post by SPeace-ATL over on ffcars.com here:

https://www.ffcars.com/posts/3078353/

I would venture to say that he has rebuilt hundreds if not a couple thousand T5's and he helped me with an issue I was having on one of my T5's. Told me what he thought was wrong and absolutely nailed it.

Thanks. The shifting is smooth, no problems. The rattle seems pervasive across the rpm range. And the rattle is regular. As if it is related to the rotation of the some spinning piece. Thanks for the link.

AeroCoupe · Jul 1, 2026

It’s a bearing preload or failure issue.

MoggieOwner · Jul 1, 2026

AeroCoupe said:
It’s a bearing preload or failure issue.

Forgive a poor layman Morgan owner: What does "bearing preload" mean.? What bothers me a lot is that my first T5 failed with a bang and then 5th rattling like a combine. And now, brand new T5, rattling (without the bang), but still. Two new T5s both defective? Or did we do something wrong when fitting them?

Noobz347 · Jul 1, 2026

MoggieOwner said:
Or did we do something wrong when fitting them?

If by "fitting" you mean "installing" then no. It is very unlikely that the install did anything to the transmission itself.

Now, this does [not] mean there wasn't an issue with the clutch install.

Bearing preload is the torque setting and/or engagement measurement required for a component during install. An example would be a bearing or seat that is installed at one torque, backed off, and re-torqued to the operating spec. If not done correctly, it can cause issues. Not your fault if this is the case. It's the fault of the whomever built the transmision.

One other thing comes to mind:

I've [never] had to do this with a Fox bell housing and a T5 but... You may want to check bellhousing runout and ensure that trans is completely centered when installed. There may be some slop somewhere if this issue recurring.

AeroCoupe · Jul 2, 2026

The input shaft and counter have shims to set the preload on the bearings. It’s super common for the input shaft to fall out of spec over time and less common for the counter shaft but parts do wear over time.

The service manual for the T5 is here:

Resource icon

T5 Rebuild Manual

Oct 2, 2013

T5 Rebuild Manual

T5- Z spec 5th gear problem

ndy846

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General karthief

wonder how much it would cost to ship you a pair

MoggieOwner

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AeroCoupe

lube between the nut and the face. I know my lubes

MoggieOwner

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AeroCoupe

lube between the nut and the face. I know my lubes

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Noobz347

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AeroCoupe

lube between the nut and the face. I know my lubes

T5 Rebuild Manual

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T5- Z spec 5th gear problem

New Member

StangNet's favorite TOOL

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New Member

New Member

wonder how much it would cost to ship you a pair

New Member

lube between the nut and the face. I know my lubes

New Member

lube between the nut and the face. I know my lubes

New Member

Stangnet Facilities Maint Tech... Er... Janitor

lube between the nut and the face. I know my lubes

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