Magnum XL hard 2-3 shift when hot

[captdistraction]

Correct me if wrong, but that involves swapping the third gear, the synchronizer assembly (from advanced to symmetric) - then just the blocker rings while in there.

Next time I go in, I'll definitely do all this, but hopefully I'm at least a little ways away from needing it.

 

[67GTA]

Correct me if wrong, but that involves swapping the third gear, the synchronizer assembly (from advanced to symmetric) - then just the blocker rings while in there.

Next time I go in, I'll definitely do all this, but hopefully I'm at least a little ways away from needing it.

That’s exactly right. Texas Drivetrain Performance sells just the synchronizer outer ring for the synchro 3-4 assembly (link below). They also sell the replacement 3rd gear with non-advanced design.

The carbon blocker rings are a Tremec part number TUES10357. You’ll have to search a bit to see who has them in stock - Tick Performance had them when I upgraded a couple years ago.

https://txdrivetrain.com/product/tr6060-3-4-slider-advanced/

 

[67GTA]

3rd gear Fix? How fixed is that exactly? I’m looking at converting mine to a dog box but libertys build time is 20 weeks….would this fix be good enough or am I still doomed?

Carbon blockers on 3-4, symmetrical tooth 3rd gear and replacing the plastic shift fork pads with bronze pads would have you in business - worlds better than it was stock. About $500 in parts and the R&R is something you could tackle in a weekend.

 

[Fabman]

Carbon blockers on 3-4, symmetrical tooth 3rd gear and replacing the plastic shift fork pads with bronze pads would have you in business - worlds better than it was stock. About $500 in parts and the R&R is something you could tackle in a weekend.

It’d sure be cool if somebody made up an upgrade kit with all the correct pieces…..probably would be a popular product…. vendor’s?

 

[67GTA]

Correct me if wrong, but that involves swapping the third gear, the synchronizer assembly (from advanced to symmetric) - then just the blocker rings while in there.

Next time I go in, I'll definitely do all this, but hopefully I'm at least a little ways away from needing it.

The carbon blocker rings are a Tremec part number TUES10357. You’ll have to search a bit to see who has them in stock - Tick Performance had them when I upgraded a couple years ago.

One other note on using this Tremec part # for 3rd & 4th; you won’t find anyone list this as a replacement for 3-4. That’s because you reuse the inner cone from your existing blocker ring. There’s no friction material on the inner cone of 3-4, so I just scuffed the surface up with a very light Emory cloth. This was the only way I could get a true full-carbon setup for 3-4 back in 2020.

Synchrotech transmissions has since started making a full-carbon 1-6 kit that comes with bronze pads, or you can source the individual pieces if you don’t need all of the blocker rings. With all of theirs, you reuse the outer ring and the inner ring from the OE Tremec bits. The friction material is what wears out or glazes, so reusing these OE pieces is perfectly acceptable - just comes down to preference on using Tremec brand friction material or going with Synchrotech.


https://sync-trans.com/products/copy-of-syn-t56-12-carbon-synchro-center-friction-ring-1-2-t56-t45

 

[67GTA]

Here’s some pics comparing the 2 different friction materials - carbon on the left, bronze on the right. This is the bronze rings that I removed after 2,000 miles - they glazed after using the wrong fluid and crazy gear clash ensued on 4-3 downshifts.

 

[captdistraction]

Torn mine down since I don't have a working powertrain - It was pretty easy to do, was able to get all the blocker rings out without needing a press (just two puller kits combined into one long puller system). Gears looked great, and even most of the blocker rings. I was surprised to see every gear with a hybrid ring set (as I thought typically these featured a double carbon blocker on 2nd). Ordered 4 of the synchrotech rings and some replacement brass fork pads. I also have a new 3-4 fork as I was told my previous one had to be welded up, but I can't find any signs of where or how they did it. Either way, will get her freshened up. At the point where its scary to think of how all this goes back together. That said, its dirty now but everything will get washed and put together cleanly.

 

[Fabman]

Torn mine down since I don't have a working powertrain - It was pretty easy to do, was able to get all the blocker rings out without needing a press (just two puller kits combined into one long puller system). Gears looked great, and even most of the blocker rings. I was surprised to see every gear with a hybrid ring set (as I thought typically these featured a double carbon blocker on 2nd). Ordered 4 of the synchrotech rings and some replacement brass fork pads. I also have a new 3-4 fork as I was told my previous one had to be welded up, but I can't find any signs of where or how they did it. Either way, will get her freshened up. At the point where its scary to think of how all this goes back together. That said, its dirty now but everything will get washed and put together cleanly.

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You are a braver man than I……I ordered a fresh gearbox and the recommended upgrade parts as per @67GTA and need to find someone local that will understand what we are trying to do….stay tuned.

 

[captdistraction]

At this point I have literally nothing to lose

 

[captdistraction]

An update on findings now that I've had it apart:

• The blocker rings looked reasonably OK, but were all hybrid rings. The double carbon blocker which is typically used on 2nd gear was also just a hybrid brass
• Third gear blocker ring showed some signs of wear with a darkened ring, but really didn't look that bad. Reverse gear also had a similar ring, oddly enough (as I never use it)
• The brass fork pads looked pretty rough, and 6th and reverse had plastic pads still
• 3rd gear (non-symmetrical/advanced) had some wear on the engagement teeth - nothing critical yet but definitely something that would contribute to hard shifting
• 3/4 synchronizer had some odd wear as well - 4th gear (symmetric side - teeth peeling back), 3rd gear looked mostly ok
• 3/4 synchro center section - it had signs of significant wear on the mating face, sharp edges worn into it, darkened oil and hot spots
• 3/4 synchro outer ring - burrs on the sliding guides - the burrs the likely cause of my shifting issues
• 1/2 synchro outer ring - burrs on the sliding guides- cleaned up with a dremel nicely
• This transmission had some rem polishing back when I bought it - but I can't find much signs of that

Synchro observations:

TUES11858 (1/2 synchronizer hybrid)​

Looks ok - replace​

​

TUES11858 (1/2 synchronizer hybrid)​

Looks ok - should be carbon/carbon -replace​

​

TUES11859 (3/4 synchronizer hybrid)​

Moderate Wear ring down center of brass side - replace​

​

TUES11861 (5/6/R synchronizer hybrid)​

Looks ok (out of focus picture above) -reuse​

​

TUES11861 (5/6/R synchronizer hybrid)​

Light Wear Ring down center of brass side - reuse​

​

TUES11861 (5/6/R synchronizer hybrid)​

Light Wear ring down center of brass side - reuse​

​

TUES11859 (3/4 synchronizer hybrid)​

Looks ok - replace​

Now comes the fun part of remembering how all this stuff went back together. I picked up the following parts to rebuild it:

• New center Carbon/carbon friction rings for positions 1-4 blockers
• New synchronizer for 3/4 (non-advanced/symmetric) - I had only intended to buy the outer hub, but was fortuitous to have bought the whole assembly since I needed a spare inner hub to replace the bad one.
• New 3rd gear (non-advanced, symmetric) - seen in black phosphate below.
• New shift fork for 3/4 (I had been told in the past my 3/4 fork needed welding, and figured I should replace it - but I can't find the signs of welding. Either way, new one going in)
• New brass pads for all positions (1-4, 5-6-R)
• new temperature sender as I broke the original's retaining tab on the connector - they're way too frail for motorsports use, looking for an alternative for future
• I had some new seals, but I'm leaving the existing ones in there as they look great

 

[Fabman]

An update on findings now that I've had it apart:

• The blocker rings looked reasonably OK, but were all hybrid rings. The double carbon blocker which is typically used on 2nd gear was also just a hybrid brass
• Third gear blocker ring showed some signs of wear with a darkened ring, but really didn't look that bad. Reverse gear also had a similar ring, oddly enough (as I never use it)
• The brass fork pads looked pretty rough, and 6th and reverse had plastic pads still
• 3rd gear (non-symmetrical/advanced) had some wear on the engagement teeth - nothing critical yet but definitely something that would contribute to hard shifting
• 3/4 synchronizer had some odd wear as well - 4th gear (symmetric side - teeth peeling back), 3rd gear looked mostly ok
• 3/4 synchro center section - it had signs of significant wear on the mating face, sharp edges worn into it, darkened oil and hot spots
• This transmission had some rem polishing back when I bought it - but I can't find much signs of that

Synchro observations:

TUES11858 (1/2 synchronizer hybrid)​

Looks ok - replace​

​

TUES11858 (1/2 synchronizer hybrid)​

Looks ok - should be carbon/carbon -replace​

​

TUES11859 (3/4 synchronizer hybrid)​

Moderate Wear ring down center of brass side - replace​

​

TUES11861 (5/6/R synchronizer hybrid)​

Looks ok (out of focus picture above) -reuse​

​

TUES11861 (5/6/R synchronizer hybrid)​

Light Wear Ring down center of brass side - reuse​

​

TUES11861 (5/6/R synchronizer hybrid)​

Light Wear ring down center of brass side - reuse​

​

TUES11859 (3/4 synchronizer hybrid)​

Looks ok - replace​

Now comes the fun part of remembering how all this stuff went back together. I picked up the following parts to rebuild it:

• New center Carbon/carbon friction rings for positions 1-4 blockers
• New synchronizer for 3/4 (non-advanced/symmetric) - I had only intended to buy the outer hub, but was fortuitous to have bought the whole assembly since I needed a spare inner hub to replace the bad one.
• New 3rd gear (non-advanced, symmetric) - seen in black phosphate below.
• New shift fork for 3/4 (I had been told in the past my 3/4 fork needed welding, and figured I should replace it - but I can't find the signs of welding. Either way, new one going in)
• New brass pads for all positions (1-4, 5-6-R)
• new temperature sender as I broke the original's retaining tab on the connector - they're way too frail for motorsports use, looking for an alternative for future
• I had some new seals, but I'm leaving the existing ones in there as they look great

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Jesus.

 

[captdistraction]

Finished the rebuild - really straightforward once you've done it once (and make sure you have a good set of snap ring pliers, and a good set of lock ring pliers - I learned halfway through there's a difference, and while you can use snap ring pliers for all, you'll fingers will appreciate the lock ring tool).

The hardest part is getting the gearsets/shafts together (the input shaft and main gearshaft/output shaft mated, countershaft/clustergear, selector shaft, 5-6-R fork shaft) and not having the unit go into "double gear" (forks selecting 2 and 4 gears simultaneously and locking the transmission). There's some acrobatics involved if you are doing this yourself, a helper at that stage is critical IMHO. I had to run through it a couple times, and other than that, the occasional gotcha as the tabs in either side of the triple cone blockers didn't initially seat making the stack taller than it should be. One final bit of self-inflicted grief was as I installed the reverse gear, I had one leftover radial needle bearing. I couldn't place it and in my pictures from teardown it appeared to be in the stack towards the top/output - well, a quick review of the manual and I realized it was supposed to be between the input and output shafts (there's both a thrust needle bearing, and a radial one to locate the nose of the output shaft in the receiver of the input assembly). So I had the exciting opportunity to practice what I learned and tear the transmission down a second time.

Once done, the parts I pulled out of the transmission included:
some worn brass pads, one set of plastic OEM pads
4 hybrid friction rings (positions 1-4)
3/4 synchronizer assembly (inner gear hub, outer ring and springs)
3rd gear (advanced)
3/4 shift fork (one that had been welded during a previous refresh).

Next time, I'll consider doing the bearings but for now they looked great. I'll definitely replace the snap rings next time - inexpensive and they can only be moved so many times. Same for front and rear seals (but for now they looked great).

 

[EF1]

Finished the rebuild - really straightforward once you've done it once (and make sure you have a good set of snap ring pliers, and a good set of lock ring pliers - I learned halfway through there's a difference, and while you can use snap ring pliers for all, you'll fingers will appreciate the lock ring tool).

The hardest part is getting the gearsets/shafts together (the input shaft and main gearshaft/output shaft mated, countershaft/clustergear, selector shaft, 5-6-R fork shaft) and not having the unit go into "double gear" (forks selecting 2 and 4 gears simultaneously and locking the transmission). There's some acrobatics involved if you are doing this yourself, a helper at that stage is critical IMHO. I had to run through it a couple times, and other than that, the occasional gotcha as the tabs in either side of the triple cone blockers didn't initially seat making the stack taller than it should be. One final bit of self-inflicted grief was as I installed the reverse gear, I had one leftover radial needle bearing. I couldn't place it and in my pictures from teardown it appeared to be in the stack towards the top/output - well, a quick review of the manual and I realized it was supposed to be between the input and output shafts (there's both a thrust needle bearing, and a radial one to locate the nose of the output shaft in the receiver of the input assembly). So I had the exciting opportunity to practice what I learned and tear the transmission down a second time.

Once done, the parts I pulled out of the transmission included:
some worn brass pads, one set of plastic OEM pads
4 hybrid friction rings (positions 1-4)
3/4 synchronizer assembly (inner gear hub, outer ring and springs)
3rd gear (advanced)
3/4 shift fork (one that had been welded during a previous refresh).

Next time, I'll consider doing the bearings but for now they looked great. I'll definitely replace the snap rings next time - inexpensive and they can only be moved so many times. Same for front and rear seals (but for now they looked great).
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You are much braver than I am. I do most things on my car myself, but after seeing this I am not sure I would try to tackle this one.

 

[captdistraction]

You are much braver than I am. I do most things on my car myself, but after seeing this I am not sure I would try to tackle this one.

Its honestly not bad now that I've done it.

Big things are a table with a hole through it to mount the trans on with some small bits of 2x2.
Then ideally a 6 foot table to lay out the parts in order and photograph as you go

Tools:
two puller sets (to combine to make one super long puller set) - some union nuts from home depot motorsports to tie them together
screwdrivers and various picks
punch set
snap ring pliers and lock ring pliers
a couple sockets and wrenches
Files, and a dremel with a sanding wheel to polish out anything you find that can be remediated
A press is necessary to re-assemble the output shaft, but if you have a buddy borrow time on theirs

If you don't change bearings, you don't have to worry about shimming or the endplay measurements - but even they're easy.

It seems pretty wild to see all the parts, but honestly there's a repeating pattern with every gear pair that makes sense ( gear with needle bearing, spacer, then triple cone blocker assembly, then synchronizer assembly, then triple cone blocker for next gear, spacer and gear/needle bearing, some sort of lock, and then repeat). I also leaned on some youtube videos and a TR6060 manual.

At the end of the day, I was quoted about $1200+parts to do this. All in with tools, the refreshed pads, blocker rings, fork, synchro assembly and new 3rd gear I'm at $620 and I have the confidence to repair this thing should I encounter trouble down the road (and I have a much better understanding of how it works).

 

[EF1]

My Magnum XL only has a couple of thousand miles on it. Hopefully I don't have any issues for a long time. When the time comes I may consider giving it a go.. The worst thing that can happen is I can't figure out how to put it back together and have to buy another trans or take the current one in milk crates to someone who really know what they are doing.

 

[JDee]

What was that movie where one of the characters said "A man's gotta know his limitations."?
So for me, that comes to stuff like this.
I truly applaud and admire those who can do these things, but for some of us, especially me, it's best to let those who can do and those who can't, (me) pay the bills.

 

[Fabman]

What was that movie where one of the characters said "A man's gotta know his limitations."?
So for me, that comes to stuff like this.
I truly applaud and admire those who can do these things, but for some of us, especially me, it's best to let those who can do and those who can't, (me) pay the bills.

Agreed....of the many things I am comfortable messing with, transmissions aren't one of them.
Major props to those who brave the myriad of gears, shafts and bearings and other mysterious pieces that look to me more like opening the back of a pocket watch than something automotive....

 

[Fabman]

I received my new Magnum XL from Dean at Kohr and the recommended upgrade parts and newest model s1sequential shifter to try out.
Sent the trans to Shaun at AED for the upgrades while I am building the Turbo system for his drag car.
Hopefully we will both have something to be happy about when the dust settles. Stay tuned.

 

[JeffV8]

I received my new Magnum XL from Dean at Kohr and the recommended upgrade parts and newest model s1sequential shifter to try out.
Sent the trans to Shaun at AED for the upgrades while I am building the Turbo system for his drag car.
Hopefully we will both have something to be happy about when the dust settles. Stay tuned.

I hope your shifter works as it should out of the box..

 

[Fabman]

I hope your shifter works as it should out of the box..

Me too. How is yours working now that you did that mod? Yours on the road yet?