MV Tooth Extraction, at Weare Rally - Transmission Problems

[Grant Bowker]

The original scale of spares lists transmissions at 4 per 100 vehicles per 12 months so on first glance the plan of 1 spare for 3 trucks seems a bit cautious. On the other hand, what good is less than a complete transmission if the plan is to be able to replace the assembly?
Another way to look at is that you are going to hold an 8 year stock (if my math is good) on a scale designed for service driving, use and abuse....... and much longer on your kinder driving, lower mileage and better maintainance program. You should be good for life.

[Lynn Eades]

Grant, Phil is scaling, based on a 25 year projection.

[Phil Waterman]

Hi All

When I started the thread I thought it would be more about the show and less about broken transmission teeth. But the search for new parts has been quite enlightening. So I requested that it be moved to the Restoration Forum.

Cheers Phil

[Phil Waterman]

Hi All

As of this afternoon a NOS Transmission is being shipped to me from Tim Tygarts http://www.obschevy.com/ of Nashville, Georgia USA. What is a bit strange is that the transmission was purchased by them with a lot of other Chevy parts probably 20 years ago. From the other photos it has only very light surface rust. They had to build a shipping crated to ship it so it will be interesting to see when it arrives.

This transmission was not listed in their online catalog in talking with the people down there they have a lot of parts which they have only a couple of which they do not list. So if you are looking for a particular part it may be worth contacting them. I have found them to very responsive to both phone and e-mails. Yes they do know how and are willing to ship overseas, though they did add the comment that shipping cost out side US or Canada often exceed the cost of the parts.

As I mentioned earlier I also found two used transmissions at Jim Carters http://www.oldchevytrucks.com/ both of them have the same casting numbers as Chevy CMPs. But again they were not listed in their catalog or web site it took contacting them with part numbers and specific request. They likewise were very responsive getting back to me within 24 hours with photos.

I will be posting more detail on this on my web site near future.

Who was it that had a broken transmission case a couple of years ago? Did you find a replacement?

Cheers Phil

[Bob Carriere]

Hi Phil

Just wondering if all the old ones you found at Jimmy's and the NOS one..... could they have different gear ration.......??? CMPs being rather unusual.

Was down for the Lobstawh festival in Maine..... a shame to drive by within 30 miles of your place and not have the time to stop in Temple.

Bob

[Phil Waterman]

Hi Bob

As the NOS and one of the others have the same open drive shaft rear out put housing I suspect that they will be the same gear ratio as the CMP because the open rear drive shaft was used on the bigger trucks and the closed torque tube drive shaft on the smaller trucks. I'm trying to find which gear ratios actually were different as offered by GM at the time. Know that 3rd is one of the gears the was different because most parts sources are specific about the number of teeth my CMP is 33 teeth on third gear, well more exactly it is 32 and 1/4 teeth.

One tip I have heard for telling the different lower clusters apart is that the big truck lower cluster has two groves machined in to the shaft see photo. I have not found how to determine which gears goes with what on the upper cluster.

One bit of information about both Jim Carter Parts and Obsolete Chevy they both will ship world wide I asked and they confirmed.

As to being in New Hampshire and not stopping by we would loved to see you and Joyce. But it would have added at least another 3 hours to your driving time plus however long we would have spent catching up. Just catching up could take a couple of days. Maybe next time we could plan a stop over. I'll take a picture of the view from the quest room and send it. Tell Joyce we have owls.

Cheers Phil

[Phil Waterman]

Hi All

NOS transmission left Nashville, GA in a crate weight 131LBS arrived 4 days later in New Hampshire weight 85LBS and minus the crate. UPS can't explain what happened to the crate. Picture of how I found it sitting by the shop.

Transmission was insured for the full value/cost $1200.00 so I don't think UPS would have accepted it wrapped in plastic. Seller is annoyed because they spent the time and effort and charged me for it to build a crate. Had I been home when it was left by UPS I would have raised a stink right then. On the back of the shipping shipping label which had been incorporated into the plastic wrapping you could see the imprint of the wood it had been pealed off of.

Spent the day disassembling and cleaning the transmission, had to completely disassemble it to clean all the bearing which had been coated in a cosmoline type preservative when the transmission had been built. Oh what a joy to actually work on a New Transmission though. Kerosene and Gunk followed by washing in 180F water and the transmission is now clean inside and out. Had to clean the bearings so I could check the run out of the shafts.

My big concern was and is the input shaft (see photo) as it is only part that could be be damaged easily by dropping the transmission. Checking the Chevy heavy truck manual it gives run out or out of true "note more than .004 inch" when I checked the shaft on the new transmission it measures .010-.012 with dial indicator. All of it is in the first inch the part goes into the pilot bearing of the flywheel. One from the old transmission reads +/-.001" measuring it the same way. Only bearing that is not 100% smooth is the front input shaft bearing. The front bearing retainer that the throw out bearing assembly rides in and out is perfectly true.

I think UPS owes me the cost of new input shaft and bearing, if Obsolete Parts can supply a new shaft and bearing I would rather just replace this one instead of having to install it in the truck to see if the clutch disengages and correctly. Your thoughts?

Bob the gear ratios are all the same on the NOS transmission all the gear tooth counts match between the transmissions. Today I received the replacement 3rd gear so I should get through this with a NOS trans in the truck and a good repaired one on the shelf.

Cheers Phil

PS- Obsolete Parts is being really good to work with. The transmission originally came from a large surplus or parts dealer in the Toronto area some twenty years ago, no one remembers the name other than they are gone now.