3rd gear grind

[Spit_Newbie]

Hello all, Just got my new clutch, slave and master cylenders installed. Took a trip around the neighborhood a couple times and found that 3rd gear grinds when i up shift and makes a rough sound while in gear. Any suggestions? Its a 3 rail trans in my 74 Spit. This is all new to me. Thanks, "Spitnewbie"

 

[70herald]

I would pop it open and see what the gears look like. Grinding going into 3r is probably do to a worn syncro ring which is easy enough to solve. but the rough sounds could be a sign of damaged gears. Once you open it up, take a look and see if the gear appear to be chipped. Also look for bits of metal in the oil.

 

[DougF]

Did it make any noises prior to the clutch and hydraulics work? Is it making any grinding noises going into first or second? Did you touch anything else besides what you describe?

 

[Spit_Newbie]

The car did not run when i took on the project so i cant say what it did befor the work. When i had the trans out, i looked at the gears and i did notice a chewed up gear. im sure thats my issue. the syncro ring sounds like it needs some looking into. this is all new to me but fun at the same time. do i need to take it to a specialist or is this a weekend job?
Thanks for the info. "Spitnewbie"

 

[DougF]

If you have the manuals to walk you through the job and the necessary tools, I sure you can do it yourself.
I would evaluate what you need in parts, bearings, seals, synchros, gears etc. Find out what these parts will cost and determine what a rebuilt or good used tranny would cost and take the best route.
If one bearing is bad, replace both. I would replace all the synchros and the seals.

 

[TR6oldtimer]

By just asking the question tells me you better send it out for repair.

I am sure members will have recommendations on who does a good job repairing these boxes.

 

[austin10_4]

interesting issue, and one i had on the Jag for a long time. As soon as it started to get to the constant grinding stage i thought i better take a look and when i did it was clear to see that the 3rd gear was slipping due to a broken tooth on it. it was easy to replace and only cost about £30 (not sure what that is in US$) very easy operation and could easily be done in a weekend with all the replacement parts, manual (if needed!!) spanner can of WD40 and a beer.

 

[70herald]

The car did not run when i took on the project so i cant say what it did befor the work. When i had the trans out, i looked at the gears and i did notice a chewed up gear. im sure thats my issue. the syncro ring sounds like it needs some looking into. this is all new to me but fun at the same time. do i need to take it to a specialist or is this a weekend job?
Thanks for the info. "Spitnewbie"

If you noticed a chewed up gear, then quite likely, the gear laygear (the hidden one under the mainshaft) is also chewed up. At that point, it starts becoming expensive.
I would start watching fleabay and see what comes up, (they frequently sell for cheap enough that it is worth the risk)
Now there are several different version of the gear box. the three rail one come in either 3 or 4 syncro versions, and the internal parts aren't really compatible.

Now if you find some extra gear boxes, and either don't mind swapping until you find a good one, that is one method. If you are patient and willing to do some careful measurements, it is quite possible to rebuild them by yourself, however it turns out that you need more than a few parts, it may not be that economical. For example, you say the 3rd gear is damaged, Spitbits lists that at $74, if the laygear is damaged, that is $200 and you still need $40 for new syncro rings. At this rate, you are half way to the cost of getting a rebuild gearbox, any you still haven't replace the oil seals, bearing or anything else.
Basically, to make it worthwhile you need to have a supply of several extra boxes and there still is a risk that you will have to buy a few expensive bits.

By the way, I have this exact same type of gearbox fully disassembled right now waiting to be put back together. One box had rather worn teeth, the other very worn bearings, the 1/2 syncro hub was shot on both of them.... However, the cost of shipping a gearbox overseas kind of tips the balance! Of course after I started I found someone locally who had a fully rebuilt unit. Oh well.