T5 5th Gear "Rattle"

Mickey Richaud · February 06, 2018, 07:37:46 PM

Folks: I've read that T5's can be noisy, especially in 5th. The World Class T5 in my GT has had a rattle in 5th since I installed it. Consequently I had it rebuilt by Stan at Pro-Force Performance in Georgia (nice guy, and came recommended), as it had other issues; but it is still noisy in 5th under load under 50 mph, and sometimes in 4th around same rpm (though not nearly as loud). Once it gets up to speed it's quiet, but kinda bothersome otherwise. With the 3.9 rear end, I'm often at a speed where 4th gear the engine rpm runs a bit high for comfort/economy, and 5th gear too low (rattles).

I'm running Pennzoil Synchromesh fluid, per Stan's recommendation. Anything better out there, or is that the fluid of choice?

Hope this makes sense! And thanks for any input.

Mickey

mgb260 · February 06, 2018, 08:42:55 PM

Mickey, I think Synchromesh oil is the best. I would check transmission mount and U joints. Could also be the snap ring that keeps the gears in place came loose.

Mickey Richaud · February 07, 2018, 06:27:12 AM

Thanks, Jim.

I emailed Stan, and he said the rear cluster shaft bearing might need a thicker shim. I've asked him if this is something I can live with, or if it has to be addressed to avoid failure. The adventure continues!

Mickey Richaud · February 07, 2018, 08:01:54 AM

If it were the snap ring, would it not make noise in all gears? Same with mounts and u-joints? The noise is really only in fifth and very rarely in fourth, both under load/lugging situation.

MGBV8 · February 07, 2018, 10:01:20 AM

Wrong stuff, Mickey.

Synchromesh is for Non-World Class T-5 transmissions with brass synchros.

World Class T-5 transmissions all use ATF. The composite fiber lined synchros do not do as well with Synchromesh.

Mobil 1 ATF (synthetic) come highly recommended. I have been using Valvoline synthetic ATF for many years now.

Loose countershaft bearing is a good possibility.

Stop lugging the engine.

IaTR6 · February 07, 2018, 11:32:08 AM

So, Pro-Force says it may need to have the counter gear shimmed? Shouldn't that have been done at the time of the rebuild?
I have had two "rebuilt" transmissions, both advertised as "heavy duty", when in fact they were both standard 265 ft lb rated.
The first had an interior case that looked like an old crankcase it was so dirty. The second, had the 5th-reverse pivot bolt removed, and
reinstalled finger tight without sealant on the threads. Watch the video by Paul Cangliosi (sp?) at 5speeds.com.
Dennis

mgb260 · February 07, 2018, 03:20:24 PM

Carl, You are right on fluid recommendation but a lot of guys have switched to Synchromesh in the WC T5 instead of ATF and have smoother shifting and more durability. The older NWC T5 was supposed to use 70-90 WT G4 and has brass synchros. Synchromesh is formulated for newer transmissions and will work with both kinds of synchros.

Mickey Richaud · February 07, 2018, 04:14:01 PM

I put Synchromesh in it, based on research I'd done and Stan's recommendation. In an email this morning, Stan said he's now recommending Mobile 1 Synthetic. Suggested I drain it and see how the fluid looks, and then switch to the Mobile 1. That's the plan for now.

Stan also checked his notes on the rebuild and found that he replaced my "large fifth gear and bearings"; he then wondered if it could be the yoke or the driveshaft. Since I've had the noise from the beginning, it may well be one of those.

Thanks for the input. Keep it coming!

MGBV8 · February 08, 2018, 01:02:13 PM

Hold the phone!

QuoteI think it is "generally held" on internet forums or from people who for the most part, do not know the history or have worked on T5's since 1982. Yes 1982. My company did warranty work for GM in the early 1980's.

All non wc boxs both from FORD and GM took Dextron II. In fact I need to find some early GM NWC cases that came from the factory with orange USE DEXTRON II stickers on them and stick a picture on web to cut out this nonsense. The only NWC transmission that used gear lube was the Jeep unit.

The Jeep units where plagued with burn out issues because of this.

People don't realize that the T5 shaft to gear clearances and pilot shaft sections have fairly tight clearances. They were designed to use the lighter weight oil to get into those tight voids. Prior to the T5 the T50 used ATF as well.

Using gear lube in a NWT5 or WC is a bad thing not an improvement. You have to ask yourself what is the advantage? Some people think the thick oil protects things better, yet fail to realize shifting is effected, cooling and oil flow within the transmission are drastically reduced.

since Dexron-II is no longer manufactured, the best alternative to use is Mobil 1 multi purpose ATF or Royal Purple Synchromax. Both have worked fine for me. We use exclusively only the Royal Purple Synchromax.

Paul Cangialosi
www.5speeds.com Creators of the JT5 5 speed!

http://www.allfordmustangs.com/forums/5-0l-talk/204680-tremec-t5-transmission.html

QuoteBorg Warner (and Tremec after they purchased BW in 2008) specifically stated in their service manual that NWC was not to be serviced with gear oil, and that you should refer to the vehicle manufacturer for fluid recommendation. Ford specially stated in their owner guides and service manuals that Dexron II was the fluid to be used for NCW.

Stan Peace or Pro-Force Performance.com (an SEFB sponsor) and I went back and forth on this subject at AFM back in late 2009.

http://www.allfordmustangs.com/forum...nsmission.html

Be sure to read the response from Paul Cangialosi (of www.5speeds.com) on page 2 of that thread.

And Stan's post about the whole gear oil myth on SEFB: http://sefb.net/forums/showthread.ph...TED-01-09-2012

Modern Driveline had for years (until early 2011) stated that NWC used 70wt gear oil. No mention of Dexron II or any other ATF whatsoever. That was wrong then and is wrong now.

Stan's website on the T-5 history states this about fluid for the NWC:

http://www.pro-forceperformance.com/t-5_history.htm

Transmission Fluid

BorgWarner allowed each manufacturer to choose the lubricant for its particular application, but it seems that BorgWarner's recommendation was Dexron-II ATF from the very beginning. GM adopted the Dexron, as proven by the stickers placed on each transmission. Ford adopted Dexron as their official fluid, as proven by specifying the ATF product in their original 1983 and 1984 Field Service Manual publications. For some reason, AMC chose to continue specifying gear oil instead of ATF. The early style of Dexron is no longer available. Generic ATF such as DEX/MERC is a suitable substitute. A Ford dealer will recommend their Mercon-V ATF which is also a good substitute.

Many Internet sources insist that gear oil should be used in the Non-World Class T-5, but the documentation above clearly reveals that both Ford and GM chose to use ATF from the start. Using gear oil in a Non-World Class transmission will not significantly damage the transmission, but many times, due to Internet confusion as to what is, and is not, a World Class T-5, gear oil has been mistakenly used in the World Class units.

Update on Dexron VS Gear oil for NON-World Class T-5's:

Dexron-III ATF replaced Dexron-II in 1993. While Dexron-III meets or exceeds the previous specifications, the viscocity of Dexron-III is thinner than the original Dexron-II that was specified for the NON-World Class T-5. This thinner fluid is fine for the World Class T-5 with the lined synchro rings, but the NON-World Class T-5 with the brass synchro rings needs a thicker fluid to work optimally. As a result, Tremec has specified 30W MOTOR OIL for the NON-World Class T-5's. While Tremec has not published an official document about this, it is confirmed by an email dated 1/9/2012 from a Tremec Engineering/Support employee.

http://vb.foureyedpride.com/showthread.php?154943-What-is-the-best-kind-of-fluid-i-should-put-in-my-t-5-speed-trans

Mickey Richaud · February 08, 2018, 01:22:22 PM

Carl -

Care to translate? Not sure where that's taking me. Mobil 1 or Synchromesh or Dexron III or Royal Purple Synchromax? Any real difference?

MGBV8 · February 08, 2018, 03:02:28 PM

Biggest takeaway for me was Ford & GM always used ATF in their T-5 trannies. Dexron II (ATF that is NLA) was specified for NWC. I did not know that.

Use the Mobil 1 synthetic, Mickey. Then, try to find your noise.

mgb260 · February 08, 2018, 03:41:10 PM

Carl, Being a Jeep Guy is probably where I got my info. The old Dexron was thicker, around 20WT. Synchromesh is similar to 30WTin viscosity. I have run it in NWC and have heard many recommendations for the WC T5. It is expensive though. How much is a QT of Mobile 1 ATF?

MGBV8 · February 09, 2018, 09:14:00 AM

Good question. Will have to do some price shopping. I buy my motor oil at Wally World.

BlownMGB-V8 · February 09, 2018, 11:17:48 AM

Mobil 1 is almost as expensive as Synchromesh, but not quite. My early(ish) TKO came with documents recommending Synchromesh, so let's just add that to the confusion. I felt like it should have been a little quicker on the shifts but I'm not sure if that means Dextron-III or Mobil 1 would be better or not.

Jim

Charles · February 13, 2018, 07:48:55 PM

Mickey, if it helps the fluid that was in my T5 is red. I know cause it drips on a white towel when we get home. I plan to fix the leak but I will need to use a BFH on the car body to make clearance to tighten the drain plug.

Get some ear plugs or go deaf like me and carry go. Carry AAA card, a cell, and credit card, and a few adult beverages for the wait on AAA.

Regards
charles

Mickey Richaud · February 13, 2018, 08:00:47 PM

Thanks, Charles - knew I could depend on you! :-)

MGBV8 · February 14, 2018, 10:02:54 AM

If I would dare park my B on a towel, it had better be black.

302GT · March 15, 2018, 08:16:49 AM

My rattle was caused by stiff springs in the clutch hub. It occurred below about 2000 rpm. The original clutch may have been a McCloud (I do not really remember...) but I now have a King Cobra and all is quiet.

Mickey Richaud · March 15, 2018, 08:33:18 AM

Thanks, Larry. Was that in all gears? Mine's only in fifth, with the occasional fourth-gear flareup.

Also, it seems like it's less pronounced when the weather's cold, until things warm up. That suggests it may be related to the fluid. Haven't switched the fluid out yet, but then I haven't driven it much either.

302GT · March 16, 2018, 10:06:58 AM

The rattle was mainly in 5th but also a little in 4th; it got worse as the transmission warmed up.

DiDueColpi · March 16, 2018, 12:48:43 PM

Hi Mickey,

Having that rattle in 4th pretty much removes the transmission from the equation.
4th gear is "straight through" and doesn't utilize any gears and very few bearings.
That only leaves everything else.
It seems that your rattle is tied to very low rpm and light load.
Some culprits could be excessively lean fuel mixture, incorrect timing, too much cam, drive shaft alignment, clutch disc (as mentioned), disc loose on input shaft, loose diffy, flywheel too light, u joints out of phase or worn etc.
Basically anything that causes play in the driveline or roughness in the engine at low rpm.
I would start by raising the car, put it in 4th gear (engine off of course) and rock the rear wheels back and forth.
You are probably going to find more play than expected.

Hope that helps,
Cheers
Fred

Mickey Richaud · March 16, 2018, 04:20:20 PM

Thanks, Fred. Will check that out; new u-joints, and pretty sure they're in phase.

Realizing that sound travels much like water leaks, the noise is centralized under the transmission tunnel. As I mentioned in the last post, I'll be changing out the fluid to see if that makes any difference.

302GT · March 16, 2018, 04:28:53 PM

I agree that the engine is causing the transmission rattle. But there is nothing wrong with the engine; it is just setting up a resonance in the transmission. When I had the rattle in my car I could lessen it (or stop it) by retarding the timing to the point where power was way down and the engine had almost no torque at 2000 rpm or less. Note that the transmission noise could be confused with heavy preignition knocking; but that was obviously not happening with the ignition timing set at 0 degrees TDC although the rattle was still present. With the King Cobra clutch, all is quiet at 14 degrees initial timing advance. The springs in the King Cobra clutch hub are absorbing torsional vibrations from the engine and keeping them from setting up a transmission resonance.

Mickey Richaud · March 16, 2018, 06:33:58 PM

Larry said, "The rattle was mainly in 5th but also a little in 4th; it got worse as the transmission warmed up."

That's what's happening, at least what I've noticed as the weather got colder. I'll try retarding the timing and see what that does. Weird, though, that it's mostly in fifth gear.