354 0r 410

[milto]

95 2500, auto 65k.



The truck originally came with a 354 rearend, the original owner had it changed over to 410. I still have the original gears and speedometer gear.



I just started pulling a 5th wheel and was real disappointed that I can only get 53 MPH when out of O/D. Plenty of power in O/D so did most of my pulling in O/D.



my question is "Should i go back to the original 354"??



Pulling in O/D at 63 MPH I'm turning 2100 and in 150 miles over various terrain it didn't kick out of O/D and my RPM never dropped more then 100-150 RPM.



Any and all suggestions will be appreciated.

 

[chuck3]

Gears

IMO, I wish they had something in between the 3. 54 and the 4. 10. I have the 3. 54 in my truck and at 75 mph I'm only turning 2000 rpm which is fine if not towing but a little fast towing but in third it seems too slow about 58 mph at 2000 rpm. Have you considered going to a larger tire?

 

[Joe G.]

milto,



For a 12 valve engine you are probably better off with the 3. 54 gears unless your trailer is very heavy and you have a lot of steep country where you tow. The 24 valve engines seem to deal with the 4. 10 gears better. They seem to have a flatter torque curve and work better turning faster.

 

[SlyBones]

Well I see 2000RPM at 70MPH, with 3. 54 gears according to the speedo and factory speedo gear. -- Chuck3 is that 75MPH because of large tires or did they change the transmission OD drive ration somewhere along the line -- Just curious.



I have the similar problem. OD is good for 65/70, about the fastest I try and tow 90% of the time. And 3rd locked is good for slow speeds or when winding it up for a big grade. Seems kinda harsh to be in 3rd locked and really reving it just to go 60 on flat ground just driving along in traffic.



I have thought about a manual unlock switch. Use 4th unlocked as a gear for 60-65 range. I figure that 91% DTT TC can handle the task. It has the drivability and the response. And as long as I keep an eye on the temp gauge it outta be OK, eh. What do ya think? Maybe get one of those transmission coolers Bill has too.



For now my general mode is to keep it over 1700RPM's in OD when towing, or just slow it down and lock out the OD. There is no middle ground. Screw the cars behind me.

 

[C Schomer]

I like my 3. 54 for my load. 75mph=2250. Craig

 

[chuck3]

SlyBones, thats 75 mph with the stock 265 tires that came on the truck in Y2K. I have a friend with a y2k truck who put bigger tires on his, it really slowed his truck down especially off the line.

 

[Howard Durand]

I pull about 6000# of trailer when we travel.

Most of our trips have been between central Washington and eastern Wyoming.

When the truck was stock, I had problems with the rolling hills.

I seemed to be in and out of OD a lot. Since I have installed the Banks Power Pak and tweaked the AFC some, I can stay in OD most of the time.

I often use the "switch" to un-lock the torque converter when the hill is just a little too tall for OD and the EGT is getting high. That will often keep me from having to drop to 3rd. If the hill is way too tall, then I lock out OD and take what I can get.

I haven't seen any appreciable rise in transmission temperature doing this. I haven't had a chance to tow since changing to the 215 injectors. Maybe I won't need the switch any more.