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Discussion Starter · #1 ·
Found this over at BON

mechanic66
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Member # 6606
posted 04 January 2002 12:44 PM
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Well, I sent Bill Franco an e-mail a while back inquiring about the infamous 1-2 crunch and how it could be normal. I was happily surprised that he got back to me and this is what he told me. Its normal No really. He was initially unaware of it because this isn't his area. He went to the tranny engineer guru guy (I shoulda asked for his name but I didn't) who was quite familiar with it and this is what he said. On the 3650's this crunch is referrred to as a "cold clash". It occurs because they use a double (my notes suck maybe double coned synchro?)synchro for 1st & 2nd and the synchros are made of high carbon steel. They did all this to make it last a long time. The engineer admitted he wasn't very fond of the crunch but it was a trade-off and it does go away when the tranny warms up. Better durability vs. smooth shifting.
Well, that pretty much is it for me. Having an explanation allows me to better understand why it is normal. I guess its time for me to shut up and drive
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http://warnerrobert.com/ubb/ultimatebb.php?ubb=get_topic&f=1&t=000864

_________________
(2) 65 verts
96 Cobra Laser Red
#1748 DHG
2005?? Cobra (Started thinking about it)

<font size=-1>[ This Message was edited by: 1NastyFordGT on 2002-01-05 15:12 ]</font>
 

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I thought so...

I figured it was something about the syncros being tight or made of something that was really cantankerous.
 

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Sounds to me like that guy is either handing or got handed a line of BS about the crunch. I dont believe that garbage for one second. If Tremec did say that then the ONLY reason they said it is to cover their a$$es about the grinding problem. Anyway my car catches in 3rd to some degree when cold as well, although not nearly as bad as from 1-2. Why wouldnt Ford know about this little piece of info with all the people that have been taking their cars in with regards to it? I call BS on this, anyone else with me?
 

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LOTS of BH being thrown around...

Lets face it, if you continue making it crunch, in the near future a trans overhaul will be necessary. It's creating wear every time it crunches. Who are they trying to $hit? And, it's NOT normal.

<font size=-1>[ This Message was edited by: Bullitt4995 on 2002-01-04 18:36 ]</font>
 

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Only time will tell. Just glad I got the 7 year 75,000 waranty. Redline D4 ATF and Prolong Transmission Additive does in fact significantly minimize the 1 - 2 "catch".

John

<font size=-1>[ This Message was edited by: TrueBlueBullitt on 2002-01-04 20:52 ]</font>
 

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According to Tremec's website (http://www.ttcautomotive.com/), the T-45 has fancier synchros (Powdered steel formed blocker rings), not the 3650 (unless there is an error on their website).

Tremec TR-3650:

This five-speed overdrive transmission from TTC was developed using state of the art technology. The TREMEC TR3450/TR3650 is designed for rear wheel drive pick up trucks & cars and is ideal for specialty sports cars equipped with high torque engines.

Features:


High contact ratio helical gears for maximum strength
Needle bearings under all gears reduces friction and noise while improving reliability.
Taper bearings on the input, main and counter shafts provide ample torque capacity.
High strength aluminum housings reduce weight
Back-tapered synchronizer splines eliminate gear jump-out
Overdrive in fifth gear helps improve fuel economy
Fifth speed synchronizer located on the counter shaft reduces rattle and shift effort
Constant mesh synchronized reverse.
Multiple shift lever locations accepted:
Front-with the shift lever directly over the case ideal for pickup trucks
Rear-(ideal for passenger cars) accommodates the lever on the rearmost part of the extension
Engineered friction materials for improved shiftability and synchronizer durability
Multiple cone synchronizers on 1st. & 2nd. Reduces shift efforts
High capacity synchronizers on 3rd., 4th., 5th. and reverse reduces shift efforts.

No.
Speed Gear Ratios
A
1 3.82
2 2.31
3 1.42
4 1.00
5 0.74
Reverse 3.82


Torque Capacity
(LBS.-FT.) 335
(N-m.) 454



Synchros
1a.-2a. Single Cone (Strut)
3a.-4a. Single Cone (Strut)
5a. Single Cone (Strut)
Reverse Not Synch.
5a.-6a.




Tremec T-45:

This five-speed overdrive transmission from TTC was developed for adaptation to a wide range of vehicle requirements. Currently the TREMEC T45 is being used on the Ford Mustang GT and Mustang Cobra.

Features:

Overdrive in fifth gear provides extended ratio coverage
Aluminum die cast housings for reduced weight
Tapered roller bearings on main and countershafts reduce noise and improve durability
Needle bearing under 1st through 4th gears improve high speed performance and reduce shift effort
Advanced synchronizer technology
Powdered steel formed blocker rings
Engineered friction material for improved durability
Double cone synchronizer design for lower shift effort in first and second speed gears
Patented strut-type synchronizer design for improved durability
Constant mesh, double disconnect reverse
Internal, single rail shift system
Integral clutch housing with front cover end-loading design for increased driveline bending strength
Multiple shift lever locations

No.
Speed Gear Ratios
A
1 3.37
2 1.99
3 1.33
4 1.00
5 0.67
Reverse 3.22


Torque Capacity
(LBS.-FT.) 250-325
(N-m.) 339-441



Synchros
1a.-2a. Single Cone (Strut)
3a.-4a. Single Cone (Strut)
5a.
Reverse Single Cone (Strut)
5a.-6a.
 

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My rear-end clunk and excess gear whine were fixed when they replaced the shift fork (different issues though, and not a result of a new shift fork). This shows something else was wrong with the transmission. Since the Redline D4 ATF minimizes or fixes the problem, why isn't Tremec specifying Redline or a fluid with similar properties? There does not have to be a so-called trade off. Also, dealers making comments about Redline not being able to handle the heat: unfounded. Redline meets and *exceeds* the warranty/quality requirements. My question to the dealer(s) would be: "What evidence do you have to support your claim that Redline cannot handle the heat in this transmission?" See http://www.redlineoil.com/products.htm:

Synthetic D4 ATF is suitable for use where Dexron III, Dexron II, or Mercon fluids are recommended. The D4 ATF is designed to satisfy the improved low-temperature requirements which will be in the new Dexron IV specification, and the improved shear-stability requirements which will be part of the new Mercon specifications. The D4 ATF also provides significantly improved gear protection and will provide a GL-4 level of gear protection, making it a superior product for transmissions and transaxles. The balanced frictional characteristics provides smooth and consistent shifts for extended drain intervals. The superior stability compared to petroleum ATFs allows high-temperature operation without varnishing valves and clutches which leads to transmission failure.


One more thing, after researching synthetic oils, it appears that there may be just ONE or TWO manufacturers in the world making "synthetic base stock". That would mean that most synthetics are essentially the same, differing only in additives for friction modifiers and stabilizers.

Why do some people NOT have any problems whatsoever? If it was normal, wouldn't every car have the problem?

After my Bullitt's transmission rebuild, the transmission now leaks (just a few drops under my parking spot, but my mechanic would not replace the trans fluid with Redline until the Ford dealer who rebuilt the transmission fixes the leak(s). This will probably require tearing the transmission apart and resealing it or replacing the transmission altogether (my choice as long as the clunk and excess gear whine do not return)).

I'm also very curious to see how much metal comes out of the transmission when the fluid is drained. I do city driving to and from work each day, and it crunches 5-7 times each way, every day.


<font size=-1>[ This Message was edited by: DrivingSimulators on 2002-01-04 22:37 ]</font>
 

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Another data point on the TR-3650:

While at Tower Records today I read Mustang Monthly's article on the Cobra where they blew the TR-3650 transmission in 2nd gear. It was replaced and did not break after further testing. They theorized that the TR-3560 was designed to be quieter and easier to shift than the old transmission (T-45? T-56?), but sacraficed strength and durability in the process.

Aparently the Tremec TKO is highly regarded, whereas the new 3650 has some teething problems (pun intended).
 

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Discussion Starter · #10 ·
Thanks for your input D S. :smile:
 

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After my 1-2 shift fork was replaced, all grinding stopped. It's still a little stiff in the cold, but not as bad as before & no more clunking noise. Obviously, the grinding & clunking wasn't normal.
 

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rancorkeeper,

Thanks for the info. My Bullitt is back at the dealer for a transmission leak. It still had gear grind in first and second after the shift-fork fix, but they did fix the clunk. I wonder if they put a different fluid in your transmission after the rebuild...
 
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