late 99 550 trans and diff question

[klinkzor]

My truck has the HD 6 speed and 4.88's in the massive rear end. Great for pulling and hauling.

I'm wondering if going to a 5 speed or if there might be another gear set available for the huge rear end. Also anyone know what rear the 550's came with that might help me find a new ring and pinion.

Reason for this question is the truck might see some highway use. The motor is screaming past 60mph and shifting 6 times by 45 gets annoying in traffic.

if more info is needed i still have the window sticker.

 

[BIG JOE]

I'm thinking there might be a 2 speed rear-end for a 550.. Or you could look into a Gear Vendor or US Gear 2 speed unit that goes in behind the Transmission ??

Contact Ford about any ratio options for the rear-end you have ?????

Joe

 

[klinkzor]

i tried the local ford dealer i got about as far as you can talking to a brick wall.

i was thinking of a gear vender option but depending on the size of it that would cause some bad pinion angle's.

 

[JLDickmon]

taller tire would accomplish the same thing...

 

[klinkzor]

it's already got the 19.5in rims and the only option i've seen for that it is the conversion to tractor trailer rims and tires and that aint very cheap.

 

[61uni]

I think it has a dana 135 in it.

 

[klinkzor]

thinks thats it now to find somewhere that has the different ratio's.

 

[BJS]

Dana/Spicer part numbers for the R&P set

3.91 Ratio Ring & Pinion Set: 360KG105-X

4.10 Ratio Ring & Pinion Set: 360KG106-X

 

[mspainting]

I've also got 550

I've also got 550 with same issue at 70 mph mine is turning 2800 rpm I've also been looking in to it. All I no is gear vendors is about $3500.00 & it will save you about 250 rpms. The regear the rear end to pay someone to do it. A good shop they quoted me $1700.00


Michael

 

[klinkzor]

now the question would be which gear to go with.

anyone know what rear gear ratio 99 f350's come with? we got one at work with the same trans and motor just different rear and the truck bogs done real bad in over drive and 5th pulls ok but once again the rpms are high in 5th but over drive is pointless