1st gear and temp question

[ForsakenLash]

Ok, gonna just narrow this down to the 1st gear issue since the temp issue is a non-issue.


First gear sometimes grinds when going in. I have to baby it in most of the time and it will still grind. It doesnt always grind, its random, but when it does it sounds terrible!!

Its looking like the syncro is out but now I need to know about that so instead of starting a new thread, just gonna narrow it down.

 

[pauleyman]

Clutch and synchros are both likely. Does you car have the hood insulating blanket

 

[DSM1G90]

Temp gauge is working normally. Motors has to run hot to be effective in their operations.

You got a Chrysler tranny there and hope the right (ATF+4) fluid is inside the tranny.

Otherwise, the felt lined syncro is having issues due to being damaged by the wrong fluid.

 

[ForsakenLash]

Id have to check on the insulation blanket. I know it has to run hot, just seems unusually hot to me... but maybe its just me...


As for the syncros... how hard is it to check those?

 

[Jward5]

If the car was running to hot you would know cause it probably wouldn't be running anymore. These cars run a bit hotter than most others its weird. Also sounds like your syncro's are toast.

 

[ForsakenLash]

Yea theres no insulation blanket on the hood... add that to my list of things to grab from the junk yard...

As for the syncros... I wonder if I drain the gear oil and put the proper stuff in if it would help at all... I mean it doesnt do it ALL the time, so maybe changing it now can save it for awhile till I can get em replaced?

 

[DSM1G90]

One trick to test syncros and I wouldn't be posting this if it meant any harm to the tranny and such:

With the car in idle: GENTLY push the shifter knob to the 1st gear position WITHOUT pushing in the clutch. If the motor idle speed gradually drops with pushing the shifter to 1st gear (it will never engage that gear or go all the way in, just a light push on the shifter knob to that gear position), the syncros are doing their job in braking down the input shaft to the motor. If you get a sudden grind, the syncros are shot and needs to be replaced.

You can do this to all forward gears to test all syncros on any manual transmission.

-DSM

 

[ForsakenLash]

One trick to test syncros and I wouldn't be posting this if it meant any harm to the tranny and such:

With the car in idle: GENTLY push the shifter knob to the 1st gear position WITHOUT pushing in the clutch. If the motor idle speed gradually drops with pushing the shifter to 1st gear (it will never engage that gear or go all the way in, just a light push on the shifter knob to that gear position), the syncros are doing their job in braking down the input shaft to the motor. If you get a sudden grind, the syncros are shot and needs to be replaced.

You can do this to all forward gears to test all syncros on any manual transmission.

-DSM

cool, ill have to check it out tomorrow thanks for the info!

 

[b18cek]

One trick to test syncros and I wouldn't be posting this if it meant any harm to the tranny and such:

With the car in idle: GENTLY push the shifter knob to the 1st gear position WITHOUT pushing in the clutch. If the motor idle speed gradually drops with pushing the shifter to 1st gear (it will never engage that gear or go all the way in, just a light push on the shifter knob to that gear position), the syncros are doing their job in braking down the input shaft to the motor. If you get a sudden grind, the syncros are shot and needs to be replaced.

You can do this to all forward gears to test all syncros on any manual transmission.

-DSM

Thanks for the info man!

 

[cisco818]

Dsm1g90 is right. But if your synchro is bad then that's gunna be a pain. You will have to remove the tranny to get to it. BUT what might actually help is putting new oil in it. Red line mt90 works well with our trannys and so does royal purple. I just switched from redline to royal purple and it shifts so smooth. If that doesn't help. you can buy the synchro from jacks transmission for only 25 bucks. I had to do my own rebuild because my first gear kept popping out. Its actually easy just time consuming. It is a transmission rebuild afterall hope it all works well for you and good luck.
P.s. royal purple is expensive

 

[ForsakenLash]

So it looks like the syncro for 1st gear is toast, or the oil in it is just causing it to act up possibly?

Are the syncros something that can be changed out one at a time or something that should be changed all at once?

None of the other gears grind, but putting them into gear is sometimes a PITA. Almost like it doesnt want to go but does if I push or pull real hard.

 

[DSM1G90]

Sorry, the fluid has nothing to do, or can help a bad syncro. It's a rebuild and best to do the entire syncro set.

On the topic of fluids: Since you're a 420A motor, you have a Chrysler tranny that ONLY uses ATF+4 fluid - nothing else.

That tranny needs a friction modifier fluid to work with those felt lined syncros that Chrysler uses. Other trannies don't need that friction modifier, thus any 75w/85-90 gear oil can be used in either dino or synth version.

I had hard shifting with my PLY, but no grinding. Changed out the fluid to MT-90 and that cured my hard shifting issue real quick.

Good luck-DSM

 

[ForsakenLash]

I hear ya, seems like MT-90 is the way to go. Im just wondering if I put the MT-90 in, if it will help keep the syncros from going completely bad until I can get them rebuilt.

 

[DSM1G90]

Nah .. just use the ATF+4 (not any other kind since the other stuff has no friction modifier compound in the fluid and that raises hell with the other syncros in that Chrysler tranny) until it's time to do the repair.

 

[cisco818]

Yes you can change the synchros. One at a time changing them all is recommended but you'll be fine without replacing all of them. And the fluid wont fix the problem but it will deffinatley smooth up the gear change. Royal purple actually cushions the gears

You know what I speak for f5m33 transmission sorry. I overlooked the fact that you have a 420a motor

 

[chico1gdsm]

Yea theres no insulation blanket on the hood... add that to my list of things to grab from the junk yard...

As for the syncros... I wonder if I drain the gear oil and put the proper stuff in if it would help at all... I mean it doesnt do it ALL the time, so maybe changing it now can save it for awhile till I can get em replaced?

What's up just stumbled on your question at what idle speed is your engine at when you shift because if it is high it will cause the grind issue

 

[ForsakenLash]

What's up just stumbled on your question at what idle speed is your engine at when you shift because if it is high it will cause the grind issue

it varies at idle because Ihave a slight timing issue and a vacuum leak that im gonna have fixed coming up very soon. However regardless of what the idle is, it is completely random at first gear, and its only 1st gear.


I am gonna get my brother in law to help me with the syncros cause he knows more about this stuff then me.

 

[Pale Horse]

Does it grind when putting the car into gear from a stop as well as downshifting say to come to a stop at a stop sign? Mine grinds only if I downshift into first while moving. For this reason I always just go second to neutral. I've never had any other issues, first gear syncros just seem touchy for some reason.

 

[ForsakenLash]

Does it grind when putting the car into gear from a stop as well as downshifting say to come to a stop at a stop sign? Mine grinds only if I downshift into first while moving. For this reason I always just go second to neutral. I've never had any other issues, first gear syncros just seem touchy for some reason.

dunno, I dont downshift all the way to first. generally I get to 3rd and then just pop it in to neutral and stop... sometimes I dont downshift at all... just kind of depends.

 

[DSM1G90]

I get to 3rd and then just pop it in to neutral and stop

The safest way to come to a stop since no clutch action is needed-just coast to the stop light/sign.

I'll do that too on occasion: drop it in neutral and coast up to close to the sign/light, then brake lightly to full stop. Then, drop the clutch right before the light hits green to shift into 1st.

 

[ForsakenLash]

The safest way to come to a stop since no clutch action is needed-just coast to the stop light/sign.

I'll do that too on occasion: drop it in neutral and coast up to close to the sign/light, then brake lightly to full stop. Then, drop the clutch right before the light hits green to shift into 1st.

thats mainly what I do, especially in traffic. But if im coming off the highway sometimes I just coast off, sometimes I downshift... but when I downshift I double clutch and rev match so I dont get the big jump in RPMs