rick harper

When replacing a ring gear and pinion, the carriers are stamped from the factory with the ratio size. But, what happens when someone changes that and doesnt restamp the carrier. You might have installed the wrong ratio. Here is the formula to check your ratio before buying the wrong part. 1, count the teeth on the ring gear. 2. count the teeth on the pinion 3. divide the pinion into the ring gear. 4. next count the teeth on the bull gear 5. also count the teeth on the helical cross. 6. divide the helical cross into the bullgear EXAMPLE: ASSUME THE CARRIER IS STAMPED 3.65 Ring gear 17 teeth pinion gear 16 teeth 17 divided by 16=1.0625 Bull gear 55 teeth helical cross 16 teeth 55 divided by 16=3.4375 Now multiply 3.4375 by 1.0625=3.65234375 or 3.65 ratio

I forgot to say that mechanical speedo's can be as much as 5MPH off. Fast or slow.

Dropping from 4.17 to 3.87 will increase your speed approx. 6MPH. This is how you figure road speed. tire factor x gear ratio x direct drive or overdrive, divided into the rpm's. EG. for 11.00R24.5, 4.17 ratio and Mack T-2090 transmission. 7.93 x 4.17 x .71=23.48. Now divide that number into the RPM's. Lets consider 1800RPM. Your speed is 76.6MPH. The tire factor for a 11.00R22.5 tires is 8.25. 7.93 and 8.25 represents brand new rubber height.

Here are the verisons of Six speeds. TRXL107 and 1071 or TRXL107A and 1071A. The A denotes air shift ILO of a double stick. The one(1) on the end denotes extra low hole 23.08 ILO 14.10. Why did Mack call it a six speed?? You only use LL in reverse or 1st hole, then use the other five speed when compound is in direct.Thats where you get the six speeds. Drove to many in the last 35 years.

1996 Mack RD690S-20713----300HP, T-2070 transmission, 18Kfronts/44Krears on camelback springs. AC,PS, radio, (10) 315/80R22.5 tires with budd wheels. 255" wheelbase with double frame. $12,000.00

Use low range only in reverse and 1st hole

List it on Ebay for one dollar($1.00). Then you will have a minimum fee. Have a buddy watch it for you and if it doesnt bring the value you are wanting have your friend bid so you wont lose it for a song and dance.

I opened a new album for this chassis. Check my gallery.

1996 MACK RD690S FOR SALE. 255"wb, 300HP, T-2070, 18FRTS, 44REARS ON CAMELBACK, DOUBLE FRAME, 10-315/80R22.5 TIRES WITH BUDD WHEELS. WAS USED IN THE ROLL OFF APPLICATION. F.O.B. TULSA, OKLA. 12,000.00

You dont have to buy a new shift knob, just cut the tap out to split.

Mack went to chassis mounted charged air cooling when the 4v head was introduced for the 1984 models.

The 07EPA engines were reliable but alot of Regen issues for the vocational markets not building enough heat to let the system regen on its own. One would have to do manual regen quite often. The EPA10 engines running DEF fluild are doing extremely good with very little regen issues. I would buy a the EPA10 engine over the EPA07 engine

He came to Tulsa in 1974 and jumped our Mack Trucks. The engine sounds like it has a bad valve seat popping back thru the exhaust.

The six cylinder 4V head was introduced in 83/84 area. The E7 were introduced in 89/90 area

Try 353GC1583P1. Mack does not show any. If this number is correct for you have your local Mack dealer call Lippert to see if they have any.

Name: Mack AB (1926) Date Added: 17 January 2012 - 04:07 PM Owner: rick harper Short Description: None Provided View Vehicle

R models never had sq. headlamps like the RWS/L or RW models. Someone has glassed those in.

Im going to have some wing glasses cut for my restoration project. Does anyone need some?? I havent taken my glass yet to cut so I dont know the cost yet. FYI

@ David, Its almost finished. After almost eleven years. I have posted new pictures in my gallery.

I can buy one at the Mack factory for 11,288.06 and that is at cost. If someone needs this that is a great price.

Name: MACK B61S (1959) Date Added: 12 May 2009 - 10:33 AM Owner: rick harper Short Description: None Provided View Vehicle

I went with plastic and stratoflex. I was going to go back with copper but felt if I'm out driving it is easier to fix plastic or stratoflex on the road. Plus I didn't want to bend the copper tubing. Rick

Hey heavyhauler, Are you the one that bought the 8 hole wheel setup on ebay a few weeks ago. If so, I was the one that sold you that package. Rick

Hello Everyone, Took about two years off the restoration because of a divorce. Now I'm ready to get back to the project. Just recently put the aluminum tube type wheels and tires on chassis. Will be putting the new wiring harness in next week. I have posted some new pictures. They are in my album and in the garage category. Will send more pictures when they are deemed. Rick Harper PS-wheels don't look bad for being 50 years old.