The 12 hour tranny swap

[bblass]

IceCold4x4 (henceforth known as Fox) finally got around to picking up a new transmission for his ZRX. Due to scheduling and time constraints, we only had one day to pull the motor, swap the tranny and button it all back together. Fox was an ambitious man expecting it to take 6 hours. I was a bit more conservative at guessing we would need 12. We started the day about 12:30 and quickly got to work removing the engine and noting deficiencies that might not pass tech inspection.





Pulling the motor turned out to be a surprisingly easy affair thanks to a removable frame rail, lift and couple of extra hands. I'll trade beers for strong backs on a motor pull any day of the week.





With the motor out and turned over we began working on removing the oil pan, oil pump, stator, water pump, clutch and other various accoutrements.



This being a Fox project, we of course were without a service manual. If I can offer one word of advice to anyone considering undertaking an endeavor that involves splitting the cases it's to print out the section of the service manual applicable to your task and reference it early and often. We probably wasted 2 hours on fiddling on how to split the cases, miscommunication and what else need to be removed in order to get to the tranny.









By around 6:30, we had the cases split and had identified the problem. Ample hoonery had worn down the dogs on 4th gear and it would slip out of gear with any application of throttle. The pants of hunger and a hangover taking shape, we decided this was a good time to call it and get dinner.

As we wrapped up dinner, Fox received a phone call that a gasket had finally been delivered and went to go pick it up. I prepped the mating surfaces in the interim and lined things up for the new tranny install.

Fox found a gear box out of an 80s ZX-10 and with minimal finagling and mixing of parts it dropped in fairly easily and suddenly he had a sixth gear. Honestly, I was incredibly surprised how well it fit. The actual tranny swap took us all of about 20 mins checking and rechecking our work.



With the new tranny installed we spread a thin layer of Honda bond across the case halves and prepared to mate them up again. Torque specs were followed for the crank bearings but may have been skipped in later stages by the owner. At this point I hereby renounce any liability .



Reassembly went fairly smooth but we were closing on 10 PM and attention spans we're starting to fade. Fox had been up for roughly 40 hours having driven in from Kansas City that morning and going right to work on stripping down the ZRX for our task at hand. I was coming down with a sinus infection. Mistakes were being made and tools misplaced. Rechecking our work caught a few small things and we both decided that the best course of action would be to button up the engine and resume work tomorrow. We rechecked torquings, made notes on what was missed and bagged left over parts and what pieces the corresponded to.



Closing in on 11:30 we mounted the engine back in the frame.



And at 12:15, nearly 12 hours after we began, the mighty ZRX was loaded onto a trailer, headed home to get fluids, the carbs and gas tank reinstalled.

All in all, it was an excellent day of work. We met the challenge, adapted and overcame and at no point got into a heated debate that typically goes with these sort of time constrained undertakings. That being said, if we were to ever do it again a service manual print out would have saved a lot of googling and guesswork.

Fox still hasn't buttoned it up yet, but I imagine the first time he shifts through 6 working gears the satisfaction of a job well done will make the lost sleep all worthwhile.

Here's hoping "Do-work" garage has claimed another victory. If not, well volunteer labor - you get what you pay for!

[kylepeterson]

fantastic.

really wanted to be there to show your progress and hide parts.

;-)

[bblass]

You were missed! Around 8 hours in Fox said "I can't help but feel like if Kyle were here we'd be done by now..."

I replied with "I feel the same way about a service manual."

[KevinB]

I replied with "I feel the same way about a service manual."

:D

[yamahamer]

Very nice!

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[IceCold4x4]

Yea. I still haven't turned another wrench here's hoping this weekend...

But thanks to Ben for the help. Now I've got to pray she holds oil.... Becuase I forgot to order 3 seals! Let's just hope they are good enough.

[Nice Goat]

Great job on walking us through the project.  I'd really like to watch something like this in person someday.

[IceCold4x4]

Personally I hope that's the last transmission I ever have to pull.

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[Fencejumper09]

Glad I could swing by and offer my expert opinion!!

[bblass]

Glad I could swing by and offer my expert opinion!!

An engineer's eye is always helpful!

[Mulley]

That is really impressive. I've never, ever even consider splitting a case much less swapping a transmission. I wish I could have been a part of it.

[bblass]

In our delirium Fox and I talked about doing a tech day garage party - little longer than most but an opportunity for those who've never done it come and learn. Something like rebuild a thumper from the ground up with the goal of knocking it out in a day.

Anyone have a project they'd be willing to lend for the cause? Might want to wait on @IceCold4x4 to post up on whether or not this was successful first!

[Fencejumper09]

The KDX could probably use a full rebuild!

[KevinB]

Something like rebuild a thumper from the ground up with the goal of knocking it out in a day.

Anyone have a project they'd be willing to lend for the cause?

You mean like a KTM 450 with a blown head gasket and warped head, that'll probably need a complete new head and crankshaft?

Unfortunately, I just dropped that one off at the dealer yesterday... :(

[IceCold4x4]

Ya the kdx would be a good one for a how to make a 2 smoke street legal....

And maybe next time how to install a lightweight stroker crankshaft on the zrx...

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