Transmission 1-2 Shift Grind


Mullet

FORD GT OWNER
Le Mans 2010 Supporter
Oct 21, 2008
2,461
Houston Texas
Note to self....

Hold shifter when above 7200 rpm and 2000 hp. Check

Thanks for the tip Ray. ;)

I for one am honestly amazed by the ruggedness and design of the stock gearbox having found its limit in Miami last spring... I am pretty happy with the limit :biggrin

The tranny is happy holding 2000 hp and shifting however fast you can grab the gears below 7200 rpm.... at that power level and above that rpm range you have to drive with one hand and hold it in gear :ack:ack:ack

Pretty amazing that it held that long to be honest... :banana:banana:banana
 

Neil Ressler

Ford GT Team Alumni
Nov 24, 2009
10
The problem is that we didn't have enough time inside of a very compressed program to develop a temperature compensated synchronizer for the 1-2 shift, so there is a slight gear clash on the 1-2 shift when everything is still cold. After a few minutes of warm-up the temperature rises to the level that the synchronizer was designed for and the clash goes away. I get the clash on a shift at "normal speed". I can get it to stop initially by giving the synchronizer a couple of seconds to catch up or by pulling the gear change hard, which apparently forces the synchronizer to match gear speeds before they engage. This is annoying but not serious.

Neil Ressler
 

dr914

GT Owner
Feb 11, 2009
160
Marietta Georgia
But is it not bad for the gearbox any time the gears clash, meaning when cold the car has to be driven very very gingerly??

The problem is that we didn't have enough time inside of a very compressed program to develop a temperature compensated synchronizer for the 1-2 shift, so there is a slight gear clash on the 1-2 shift when everything is still cold. After a few minutes of warm-up the temperature rises to the level that the synchronizer was designed for and the clash goes away. I get the clash on a shift at "normal speed". I can get it to stop initially by giving the synchronizer a couple of seconds to catch up or by pulling the gear change hard, which apparently forces the synchronizer to match gear speeds before they engage. This is annoying but not serious.

Neil Ressler
 
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GKW05GT

GT Owner
Mark II Lifetime
May 28, 2011
2,440
Fayetteville, Ga.
I usually go 1st to third when cold or feel resistance when shifting to 2nd. I assume this would not cause any cluthch problems but not sure
 

dr914

GT Owner
Feb 11, 2009
160
Marietta Georgia
Yes I do too.
I usually go 1st to third when cold or feel resistance when shifting to 2nd. I assume this would not cause any cluthch problems but not sure
 

dbtgt

One lucky SOB to own a GT
Mark IV Lifetime
Jan 4, 2006
1,105
Tulsa, Oklahoma
The FGT Forum "Search" is your friend. This issue has been discussed in detail years ago. It is a "normal characteristic" of our car's transaxle. Shift from 1st to 3rd until tranny warms up.
Any further info on the 1-2 grind issue? I just got my car and noticed this characteristic on mine, as well. If anyone has some guidance I can give my dealer, that would be great.
 

RALPHIE

GT Owner
Mar 1, 2007
7,279
The problem is that we didn't have enough time inside of a very compressed program to develop a temperature compensated synchronizer for the 1-2 shift, so there is a slight gear clash on the 1-2 shift when everything is still cold. After a few minutes of warm-up the temperature rises to the level that the synchronizer was designed for and the clash goes away. I get the clash on a shift at "normal speed". I can get it to stop initially by giving the synchronizer a couple of seconds to catch up or by pulling the gear change hard, which apparently forces the synchronizer to match gear speeds before they engage. This is annoying but not serious.

Neil Ressler
Thanks Neil - it's great to have your input on this issue, as it gets rid of the conjecture, and putting it to rest.

I personally make that shift very slowly, pausing as I'm entering the 2nd gear when the car is cold, and allowing the synchornizer to come up to speed. This seems to work for me.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,208
Myakka City, Florida
Thanks Neil - it's great to have your input on this issue, as it gets rid of the conjecture, and putting it to rest.

I personally make that shift very slowly, pausing as I'm entering the 2nd gear when the car is cold, and allowing the synchornizer to come up to speed. This seems to work for me.
+1 with extra thanks to Neil. This 1-2 synchro behavior is common in my experience among many manuals. Always good to take things easy until all systems are at operating temp...which can take a while with 2 1/2 gallons of oil and 8 gallons of coolant. Absolutely no issues at operating temp.
 

dr914

GT Owner
Feb 11, 2009
160
Marietta Georgia
and then there are those who floor it cold with cold tires in a curve!!!!!!!!!!!
 

glord

GT Owner
Mar 25, 2006
84
Los Gatos California
Regarding the 1-2 cold grind, my approach is to stop just short of catching second gear, move the shifter ever so slightly back towards neutral (basically just backing off the pressure on the shifter slightly) then immediatly down into second. No grind. I've had two GT and this technique has worked on both. Sounds like a pain, but it really isn't.
 

twobjshelbys

GT Owner
Jul 26, 2010
5,062
Las Vegas, NV
I have it too, and was not surprised. In fact, I almost expected it. I too just go from 1-3 until it's warmed up. I don't like being in 1 for the two blocks out of the subdivision but it's downhill so the car doesn't complain about being in 3rd to the exit.

I do find the amount of resistance does decrease with increased ambient temperature. It's very noticeable in the spring and fall, but not so much in the summer.
 

BlackICE

GT Owner
Nov 2, 2005
1,412
SF Bay Area in California
EP never had the problem.
 

glasser/09

GT Owner
Apr 30, 2014
9
Great analogy! :thumbsup
that pretty much sums it up
 

Bart Carter

GT Owner
Mar 12, 2006
272
Las Vegas
I had the problem since new. When I recently had the transmission oil changed, the "crunch" reduced by 70 percent. I have always eased it into 2nd until fully warmed. Even when fully warmed, there is still a little crunch, so I feel it in.

If some people have zero crunch, then it is the build, not the design.