TR-3650 Defects

[Lou Hiddell]

Hey guys, I'm fairly new here but I couldn't find much on this topic (maybe because I'm looking for defects that aren't even there). Anyways, I just ordered a remanufactured tr3650 from these guys, https://reman-transmission.com/transmission-codes/?code=TR3650, for an 06 GT that my son just bought because the tr3650 in it was trashed and grinding in nearly every gear. I talked to one of their reps and they claim it has had any and all of the factory defects amended but they weren't clear on what those were. Would anybody on here have any idea what defects they're talking about if any? I'm thinking we might want to beef the tranny up a bit anyway since we're planning on running around 600hp to the wheels and need it to be reliable under that power. Any advice is much appreciated

 

[rocky61201]

TR3650 History (pro-forceperformance.com)

This website and vendor is my go to guy for buying parts and rebuilding tremecs. Upgrading the input shaft is probably the most popular upgrade but you have to almost completely disasemble the transmission to put it in. Choice is yours. IMO the key to improving life and durability of the 3650 is upgraded motor mounts, a good shifter, brass shift linkage bushings, the blowfish racing shifter bracket which unfortunately is no longer manufactured, braided clutch line, and finally a properly working clutch with proper throw out bearing preload measurements. The end of result of making all these small and easy improvements is smoother and more precise shifts and not trashing the transmission by forcing it in gear. There are threads on here that cover all this stuff. Just got to search for them, and they are not to hard to find.

Edit - last bit of advice. Don't put Royal Purple manual transmission fluid in it!!! The are additives in there that will eat the carbon fiber off your snchro rings.

 

[Midlife Crises]

In general, in the 350 HP range the main problem is the synchros and the shifter. Both can be improved. Hi rpm shifting can sometimes be difficult without improving the synchros. The input shaft is known to twist or snap at power levels above stock. Custom, stronger parts have been available for the 3650 but by the time you pay for all the tweaks to hold 600 ponies you can install a better transmission with the rest of the supporting equipment. The Tremec T56 Magnum XL is a popular upgrade with multiple vendors offering bolt in kits. The kits run from basic to complete. Pretty much tell the vendor what you want to do.

 

[Juice]

Make sure you shim the slave correctly for the new clutch.

If you go Magnum XL swap, tuning will be required. Tuning as in manual transmission gear ratios updated. Or cruise will not work.

 

[Bigmatthew86]

I can tell you I’ve been trying to get my new to me 08 to shift better. I installed a Barton shifter, bmr motor mounts, vacuum bled the clutch, changed the tranny fluid, & installed a billet slave cylinder eyelet. Made a ton of difference. I feel much more confident banging gears.

 

[Midlife Crises]

I installed an MGW shifter, made first gear cry and tore second gear up. It was not the shifters fault.

 

[Midlife Crises]

Make sure you shim the slave correctly for the new clutch.

If you go Magnum XL swap, tuning will be required. Tuning as in manual transmission gear ratios updated. Or cruise will not work.

Hey Juice, my cruise works in 4th and 6th but not 5th. Were you able to correct the files and make cruise work in all gears?

 

[Juice]

Hey Juice, my cruise works in 4th and 6th but not 5th. Were you able to correct the files and make cruise work in all gears?

No, I only have cruise in 6th with the control pack tune. I also had cruise in 4th only messing with the tune.

The issue is yours had a 5 speed. Cruise only works if the pcm thinks you are in a gear, calculated by engine rpm and driveshaft speed. 4th is 1:1 with both transmissions. I bet 6th in magnum is in same range in tune as stock 5th, so cruise works.
In fifth now, the pcm is like, "wtf gear is this", and disables cruise. Make sense? Hopefully, the calibration has the ability to use a six speed gear box. (Gt500?) Guess you could use the 3,4,5 gears and enter the magnum 4,5,6 ratios.

 

[GlassTop09]

Hey Juice, my cruise works in 4th and 6th but not 5th. Were you able to correct the files and make cruise work in all gears?

No, I only have cruise in 6th with the control pack tune. I also had cruise in 4th only messing with the tune.

The issue is yours had a 5 speed. Cruise only works if the pcm thinks you are in a gear, calculated by engine rpm and driveshaft speed. 4th is 1:1 with both transmissions. I bet 6th in magnum is in same range in tune as stock 5th, so cruise works.
In fifth now, the pcm is like, "wtf gear is this", and disables cruise. Make sense? Hopefully, the calibration has the ability to use a six speed gear box. (Gt500?) Guess you could use the 3,4,5 gears and enter the magnum 4,5,6 ratios.

Easy issue to fix in SO PCM. Tune calibration for manual trans can accommodate up to a 6-speed manual tran's gear ratios.
This picture is from my current tune file in use in my Stang using HPTuners VCM Editor to capture as it is set up in tune to use a manual trans (TR3650) & cruise works.

Hope this helps.

 

[skwerl]

The 3650 won't handle 600hp. Hell, it won't handle 500hp. Best fix is a Tremec T56 Magnum upgrade. Patching the 3650 will only result in heartache.

 

[Aerofinz]

... changed the tranny fluid ...

Curious what fluid you chose to use? Thx!

 

[Bigmatthew86]

I’m running Pennzoil syncomesh. It seems to shift well but I can’t promise you it’s better then new Mobil atf. I’m also not making much power. Just a intake & tune.

 

[skwerl]

I tried several and Synchromesh just seemed like it felt 'buttery'. It felt like there was a thicker layer of fluid between the shift forks and gears. But when I got the Tremec T56 XL it specifically said to run Mobil1 synthetic so I did.

 

[Stoenr]

Easy issue to fix in SO PCM. Tune calibration for manual trans can accommodate up to a 6-speed manual tran's gear ratios.
This picture is from my current tune file in use in my Stang using HPTuners VCM Editor to capture as it is set up in tune to use a manual trans (TR3650) & cruise works.
View attachment 81456
Hope this helps.

Interesting. I only have cruise in 4th and 6th, lol. Its not a big deal, dont spend to much time in 5th anyway.
T56 Magnum.

 

[eighty6gt]

I've been rolling 600+ on 295 radials with a 3650 forever. I have steeda motor mounts, Roush shifter, blowfish. I've shimmed the slave I got used on this forum. I replaced the blocker rings in the trans via the guy in the link in one of the first few posts above. The old ones were fine, I even ran rp for a while. I used red scotch brite to longitudinally scuff the blocker ring grip surfaces on the sliders.

Great transmission.

 

[Juice]

Interesting. I only have cruise in 4th and 6th, lol. Its not a big deal, dont spend to much time in 5th anyway.
T56 Magnum.

Because you dont have the magnum 5th gear ratio in the tune. The PCM disables cruise for the smallest discrepency in gear ratio. So when you are in the new 5th, the pcm does not know how to handle it.
4 & 6 is close enough to 4&5 of the old gear box, so cruise works. (Also aplies to 1,2,3, but who uses cruise in those?)

 

[Stoenr]

Because you dont have the magnum 5th gear ratio in the tune. The PCM disables cruise for the smallest discrepency in gear ratio. So when you are in the new 5th, the pcm does not know how to handle it.
4 & 6 is close enough to 4&5 of the old gear box, so cruise works. (Also aplies to 1,2,3, but who uses cruise in those?)

Think I could make that adjustment with my handheld tuner?

 

[Juice]

Think I could make that adjustment with my handheld tuner?

Nope.